Science.gov

Sample records for aircraft composite inspections

  1. Improving aircraft composite inspections using optimized reference standards

    SciTech Connect

    Roach, D.; Dorrell, L.; Kollgaard, J.; Dreher, T.

    1998-10-01

    The rapidly increasing use of composites on commercial airplanes coupled with the potential for economic savings associated with their use in aircraft structures means that the demand for composite materials technology will continue to increase. Inspecting these composite structures is a critical element in assuring this continued airworthiness. The FAA`s Airworthiness Assurance NDI Validation Center, in conjunction with the Commercial Aircraft Composite Repair committee, is developing a set of composite reference standards to be used in NDT equipment calibration for accomplishment of damage assessment and post-repair inspection of all commercial aircraft composites. In this program, a series of NDI tests on a matrix of composite aircraft structures and prototype reference standards were completed in order to minimize the number of standards needed to carry out composite inspections on aircraft. Two tasks, related to composite laminates and non-metallic composite honeycomb configurations, were addressed.

  2. Nondestructive inspection of bonded composite doublers for aircraft

    NASA Astrophysics Data System (ADS)

    Roach, Dennis P.; Moore, David; Walkington, Phillip D.

    1996-11-01

    One of the major thrusts established under the FAA's National Aging Aircraft Research Program is to foster new technologies associated with civil aircraft maintenance. Recent DOD and other government developments in the use of bonded composite doublers on metal structures has supported the need for research and validation of such doubler applications on US certificated airplanes. Composite doubler technology is rapidly maturing and shows promise of cost savings on aging aircraft. While there have been numerous studies and military aircraft installations of composite doublers, the technology has not been certified for use on commercial aircraft. Before the use of composite doublers can be accepted by the civil aviation industry, it is imperative that methods be developed which can quickly and reliably assess the integrity of the doubler. In this study, a specific composite application was chosen on an L-1011 aircraft in order to focus the tasks on application and operation issues. Primary among inspection requirements for these doublers is the identification of disbonds, between the composite laminate and aluminum parent material, and delaminations in the composite laminate. Surveillance of cracks or corrosion in the inspection (NDI) method can inspect for every flaw type, therefore it is important to be aware of available NDI techniques and to properly address their capabilities and limitations. This paper reports on a series of NDI tests which have been conducted on laboratory test structures and on a fuselage section cut from a retired L-1011 aircraft. Specific challenges, unique to bonded composite doubler applications, will be highlighted. In order to quickly integrate this technology into existing aircraft maintenance depots, the use of conventional NDI, ultrasonics, x-ray, and eddy current, is stressed. The application of these NDI technique to composite doublers and the results from test specimens, which were loaded to provide a changing flaw profile, are

  3. Nondestructive inspection of bonded composite doublers for aircraft

    SciTech Connect

    Roach, D.; Moore, D.; Walkington, P.

    1996-12-31

    One major thrust in FAA`s National Aging Aircraft Research Program is to foster new technologies in civil aircraft maintenance. Recent DOD and other government developments in using bonded composite doublers on metal structures support the need for validation of such doubler applications on US certificated airplanes. In this study, a specific composite application was chosen on an L-1011 aircraft. Primary inspection requirements for these doublers include identifying disbonds between composite laminate and aluminum parent material, and delaminations in the composite laminate. Surveillance of cracks or corrosion in the parent aluminum material beneath the double is also a concern. No single NDI method can inspect for every flaw type, therefore we need to know NDI capabilities and limitations. This paper reports on a series of NDI tests conducted on laboratory test structures and on a fuselage section from a retired L-1011. Application of ultrasonics, x-ray, and eddy current to composite doublers and results from test specimens loaded to provide a changing flaw profile, are presented in this paper. Development of appropriate inspection calibration standards are also discussed.

  4. Development and utilization of composite honeycomb and solid laminate reference standards for aircraft inspections.

    SciTech Connect

    Roach, Dennis Patrick; Rackow, Kirk A.

    2004-06-01

    The FAA's Airworthiness Assurance NDI Validation Center, in conjunction with the Commercial Aircraft Composite Repair Committee, developed a set of composite reference standards to be used in NDT equipment calibration for accomplishment of damage assessment and post-repair inspection of all commercial aircraft composites. In this program, a series of NDI tests on a matrix of composite aircraft structures and prototype reference standards were completed in order to minimize the number of standards needed to carry out composite inspections on aircraft. Two tasks, related to composite laminates and non-metallic composite honeycomb configurations, were addressed. A suite of 64 honeycomb panels, representing the bounding conditions of honeycomb construction on aircraft, was inspected using a wide array of NDI techniques. An analysis of the resulting data determined the variables that play a key role in setting up NDT equipment. This has resulted in a set of minimum honeycomb NDI reference standards that include these key variables. A sequence of subsequent tests determined that this minimum honeycomb reference standard set is able to fully support inspections over the full range of honeycomb construction scenarios found on commercial aircraft. In the solid composite laminate arena, G11 Phenolic was identified as a good generic solid laminate reference standard material. Testing determined matches in key velocity and acoustic impedance properties, as well as, low attenuation relative to carbon laminates. Furthermore, comparisons of resonance testing response curves from the G11 Phenolic NDI reference standard was very similar to the resonance response curves measured on the existing carbon and fiberglass laminates. NDI data shows that this material should work for both pulse-echo (velocity-based) and resonance (acoustic impedance-based) inspections.

  5. Ultrasonic inspection technique for composite doubler/aluminum skin bond integrity for aircraft

    NASA Astrophysics Data System (ADS)

    Gieske, John H.; Roach, Dennis P.; Walkington, Phillip D.

    1998-03-01

    As part of the FAA's National Aging Aircraft Research Program to foster new technologies for civil aircraft maintenance and repair, use of bonded composite doublers on metal aircraft structures has been advanced. Research and validation of such doubler applications on U.S. certified commercial aircraft has begun. A specific composite application to assess the capabilities of composite doublers was chosen on a L-1011 aircraft for reinforcement of the corner of a cargo door frame where a boron-epoxy repair patch of up to 72 plies was installed. A primary inspection requirement for these doublers is the identification of disbonds between the composite laminate and the aluminum parent material. This paper describes the development of an ultrasonic pulse-echo technique using a modified immersion focus transducer where a robust signal amplitude signature of the composite/aluminum interface is obtained to characterize the condition of the bond. Example waveforms and C-scan images are shown to illustrate the ultrasonic response for various transducer configurations using a boron-epoxy/aluminum skin calibration test sample where disbonds and delaminations were built-in. The modified focus transducer is compatible with portable ultrasonic scanning systems that utilize the weeper or dripless bubbler technologies when an ultrasonic inspection of the boron-epoxy composite doublers installed on aircraft is implemented.

  6. Ultrasonic inspection technique for composite doubler/aluminum skin bond integrity for aircraft

    SciTech Connect

    Gieske, J.H.; Roach, D.P.; Walkington, P.D.

    1998-02-01

    As part of the FAA`s National Aging Aircraft Research Program to foster new technologies for civil aircraft maintenance and repair, use of bonded composite doublers on metal aircraft structures has been advanced. Research and validation of such doubler applications on US certified commercial aircraft has begun. A specific composite application to assess the capabilities of composite doublers was chosen on a L-1011 aircraft for reinforcement of the comer of a cargo door frame where a boron-epoxy repair patch of up to 72 plies was installed. A primary inspection requirement for these doublers is the identification of disbonds between the composite laminate and the aluminum parent material. This paper describes the development of an ultrasonic pulse echo technique using a modified immersion focus transducer where a robust signal amplitude signature of the composite aluminum interface is obtained to characterize the condition of the bond. Example waveforms and C-scan images are shown to illustrate the ultrasonic response for various transducer configurations using a boron-epoxy aluminum skin calibration test sample where disbonds and delaminations were built-in. The modified focus transducer is compatible with portable ultrasonic scanning systems that utilize the weeper or dripless bubbler technologies when an ultrasonic inspection of the boron-epoxy composite doublers installed on aircraft is implemented.

  7. Development of Composite Honeycomb and Solid Laminate Reference Standards to Aid Aircraft Inspections

    SciTech Connect

    Dorrell, L.; Roach, D.

    1999-03-04

    The rapidly increasing use of composites on commercial airplanes coupled with the potential for economic savings associated with their use in aircraft structures means that the demand for composite materials technology will continue to increase. Inspecting these composite structures is a critical element in assuring their continued airworthiness. The FAA's Airworthiness Assurance NDI Validation Center, in conjunction with the Commercial Aircraft Composite Repair Committee (CACRC), is developing a set of composite reference standards to be used in NDT equipment calibration for accomplishment of damage assessment and post-repair inspection of all commercial aircraft composites. In this program, a series of NDI tests on a matrix of composite aircraft structures and prototype reference standards were completed in order to minimize the number of standards needed to carry out composite inspections on aircraft. Two tasks, related to composite laminates and non-metallic composite honeycomb configurations, were addressed. A suite of 64 honeycomb panels, representing the bounding conditions of honeycomb construction on aircraft, were inspected using a wide array of NDI techniques. An analysis of the resulting data determined the variables that play a key role in setting up NDT equipment. This has resulted in a prototype set of minimum honeycomb reference standards that include these key variables. A sequence of subsequent tests determined that this minimum honeycomb reference standard set is able to fully support inspections over the fill range of honeycomb construction scenarios. Current tasks are aimed at optimizing the methods used to engineer realistic flaws into the specimens. In the solid composite laminate arena, we have identified what appears to be an excellent candidate, G11 Phenolic, as a generic solid laminate reference standard material. Testing to date has determined matches in key velocity and acoustic impedance properties, as well as, low attenuation relative

  8. Development and validation of nondestructive inspection techniques for composite doubler repairs on commercial aircraft

    SciTech Connect

    Roach, D.; Walkington, P.

    1998-05-01

    Composite doublers, or repair patches, provide an innovative repair technique which can enhance the way aircraft are maintained. Instead of riveting multiple steel or aluminum plates to facilitate an aircraft repair, it is possible to bond a single boron-epoxy composite doubler to the damaged structure. In order for the use of composite doublers to achieve widespread use in the civil aviation industry, it is imperative that methods be developed which can quickly and reliably assess the integrity of the doubler. In this study, a specific composite application was chosen on an L-1011 aircraft in order to focus the tasks on application and operation issues. Primary among inspection requirements for these doublers is the identification of disbonds, between the composite laminate and aluminum parent material, and delaminations in the composite laminate. Surveillance of cracks or corrosion in the parent aluminum material beneath the doubler is also a concern. No single nondestructive inspection (NDI) method can inspect for every flaw type, therefore it is important to be aware of available NDI techniques and to properly address their capabilities and limitations. A series of NDI tests were conducted on laboratory test structures and on full-scale aircraft fuselage sections. Specific challenges, unique to bonded composite doubler applications, were highlighted. An array of conventional and advanced NDI techniques were evaluated. Flaw detection sensitivity studies were conducted on applicable eddy current, ultrasonic, X-ray and thermography based devices. The application of these NDI techniques to composite doublers and the results from test specimens, which were loaded to provide a changing flaw profile, are presented in this report. It was found that a team of these techniques can identify flaws in composite doubler installations well before they reach critical size.

  9. X-ray inspection of composite materials for aircraft structures using detectors of Medipix type

    NASA Astrophysics Data System (ADS)

    Jandejsek, I.; Jakubek, J.; Jakubek, M.; Prucha, P.; Krejci, F.; Soukup, P.; Turecek, D.; Vavrik, D.; Zemlicka, J.

    2014-05-01

    This work presents an overview of promising X-ray imaging techniques employed for non-destructive defectoscopy inspections of composite materials intended for the Aircraft industry. The major emphasis is placed on non-tomographic imaging techniques which do not require demanding spatial and time measurement conditions. Imaging methods for defects visualisation, delamination detection and porosity measurement of various composite materials such as carbon fibre reinforced polymers and honeycomb sendwiches are proposed. We make use of the new large area WidePix X-ray imaging camera assembled from up to 100 edgeless Medipix type detectors which is highly suitable for this type of measurements.

  10. Damage criticality and inspection concerns of composite-metallic aircraft structures under blunt impact

    NASA Astrophysics Data System (ADS)

    Zou, D.; Haack, C.; Bishop, P.; Bezabeh, A.

    2015-04-01

    Composite aircraft structures such as fuselage and wings are subject to impact from many sources. Ground service equipment (GSE) vehicles are regarded as realistic sources of blunt impact damage, where the protective soft rubber is used. With the use of composite materials, blunt impact damage is of special interest, since potential significant structural damage may be barely visible or invisible on the structure's outer surface. Such impact can result in local or non-local damage, in terms of internal delamination in skin, interfacial delamination between stiffeners and skin, and fracture of internal reinforced component such as stringers and frames. The consequences of these events result in aircraft damage, delays, and financial cost to the industry. Therefore, it is necessary to understand the criticality of damage under this impact and provide reliable recommendations for safety and inspection technologies. This investigation concerns a composite-metallic 4-hat-stiffened and 5-frame panel, designed to represent a fuselage structure panel generic to the new generation of composite aircraft. The test fixtures were developed based on the correlation between finite element analyses of the panel model and the barrel model. Three static tests at certain amount of impact energy were performed, in order to improve the understanding of the influence of the variation in shear ties, and the added rotational stiffness. The results of this research demonstrated low velocity high mass impacts on composite aircraft fuselages beyond 82.1 kN of impact load, which may cause extensive internal structural damage without clear visual detectability on the external skin surface.

  11. Program for establishing long-time flight service performance of composite materials in the center wing structure of C-130 aircraft. Phase 5: Flight service and inspection

    NASA Technical Reports Server (NTRS)

    Kizer, J. A.

    1981-01-01

    Inspections of the C-130 composite-reinforced center wings were conducted over the flight service monitoring period of more than six years. Twelve inspections were conducted on each of the two C-130H airplanes having composite reinforced center wing boxes. Each inspection consisted of visual and ultrasonic inspection of the selective boron-epoxy reinforced center wings which included the inspection of the boron-epoxy laminates and the boron-epoxy reinforcement/aluminum structure adhesive bondlines. During the flight service monitoring period, the two C-130H aircraft accumulated more than 10,000 flight hours and no defects were detected in the inspections over this period. The successful performance of the C-130H aircraft with composite-reinforced center wings allowed the transfer of the responsibilities of inspecting and maintaining these two aircraft to the U. S. Air Force.

  12. Human factors in aircraft maintenance and inspection

    NASA Technical Reports Server (NTRS)

    Shepherd, William T.

    1992-01-01

    The events which have led to the intensive study of aircraft structural problems have contributed in no less measure to the study of human factors which influence aircraft maintenance and inspection. Initial research emphasis on aging aircraft maintenance and inspection has since broadened to include all aircraft types. Technicians must be equally adept at repairing old and new aircraft. Their skills must include the ability to repair sheet metal and composite materials; control cable and fly-by-wire systems; round dials and glass cockpits. Their work performance is heavily influenced by others such as designers, technical writers, job card authors, schedulers, and trainers. This paper describes the activities concerning aircraft and maintenance human factors.

  13. Assessment of state-of-the-art of in-service inspection methods for graphite epoxy composite structures on commercial transport aircraft

    NASA Technical Reports Server (NTRS)

    Phelps, M. L.

    1979-01-01

    A survey was conducted to determine current in-service inspection practices for all types of aircraft structure and particularly for advanced composite structures. The survey consisted of written questionnaires to commercial airlines, visits to airlines, aircraft manufacturers, and government agencies, and a literature search. Details of the survey including visits, questions asked, a bibliography of reviewed literature and details of the results are reported. From the results, a current in-service inspection baseline and a preliminary inspection program for advanced composite structures is documented as appendices to the report.

  14. Composite components on commercial aircraft

    NASA Technical Reports Server (NTRS)

    Dexter, H. B.

    1980-01-01

    Flight experience gained with numerous composite aircraft structures is discussed. Both commercial transports and helicopters are included. Design concepts with significant mass savings and appropriate inspection and maintenance procedures are among the factors considered. Also, a major NASA/U.S. industry technology program to reduce fuel consumption of commercial transport aircraft through the use of advanced composites is described, including preliminary results. Ground and flight environmental effects on the composite materials used in the flight service programs are also discussed.

  15. Aircraft Inspection for the General Aviation Aircraft Owner.

    ERIC Educational Resources Information Center

    Federal Aviation Administration (DOT), Washington, DC. Flight Standards Service.

    Presented is useful information for owners, pilots, student mechanics, and others with aviation interests. Part I of this booklet outlines aircraft inspection requirements, owner responsibilities, inspection time intervals, and sources of basic information. Part II is concerned with the general techniques used to inspect an aircraft. (Author/JN)

  16. Composite components on commercial aircraft

    NASA Technical Reports Server (NTRS)

    Dexter, H. B.

    1980-01-01

    Commercial aircraft manufacturers are making production commitments to composite structure for future aircraft and modifications to current production aircraft. Flight service programs with advanced composites sponsored by NASA during the past 10 years are described. Approximately 2.5 million total composite component flight hours have been accumulated since 1970 on both commercial transports and helicopters. Design concepts with significant mass savings were developed, appropriate inspection and maintenance procedures were established, and satisfactory service was achieved for the various composite components. A major NASA/U.S. industry technology program to reduce fuel consumption of commercial transport aircraft through the use of advanced composites was undertaken. Ground and flight environmental effects on the composite materials used in the flight service programs supplement the flight service evaluation.

  17. Composite components on commercial aircraft

    NASA Technical Reports Server (NTRS)

    Dexter, H. B.

    1980-01-01

    The paper considers the use of composite components in commercial aircraft. NASA has been active in sponsoring flight service programs with advanced composites for the last 10 years, with 2.5 million total composite component hours accumulated since 1970 on commercial transports and helicopters with no significant degradation in residual strength of composite components. Design, inspection, and maintenance procedures have been developed; a major NASA/US industry technology program has been developed to reduce fuel consumption of commercial transport aircraft through the use of advanced composites.

  18. Durability of aircraft composite materials

    NASA Technical Reports Server (NTRS)

    Dextern, H. B.

    1982-01-01

    Confidence in the long term durability of advanced composites is developed through a series of flight service programs. Service experience is obtained by installing secondary and primary composite components on commercial and military transport aircraft and helicopters. Included are spoilers, rudders, elevators, ailerons, fairings and wing boxes on transport aircraft and doors, fairings, tail rotors, vertical fins, and horizontal stabilizers on helicopters. Materials included in the evaluation are boron/epoxy, Kevlar/epoxy, graphite/epoxy and boron/aluminum. Inspection, maintenance, and repair results for the components in service are reported. The effects of long term exposure to laboratory, flight, and outdoor environmental conditions are reported for various composite materials. Included are effects of moisture absorption, ultraviolet radiation, and aircraft fuels and fluids.

  19. Automation for nondestructive inspection of aircraft

    NASA Technical Reports Server (NTRS)

    Siegel, M. W.

    1994-01-01

    We discuss the motivation and an architectural framework for using small mobile robots as automated aids to operators of nondestructive inspection (NDI) equipment. We review the need for aircraft skin inspection, and identify the constraints in commercial airlines operations that make small mobile robots the most attractive alternative for automated aids for NDI procedures. We describe the design and performance of the robot (ANDI) that we designed, built, and are testing for deployment of eddy current probes in prescribed commercial aircraft inspections. We discuss recent work aimed at also providing robotic aids for visual inspection.

  20. Emerging nondestructive inspection methods for aging aircraft

    SciTech Connect

    Beattie, A; Dahlke, L; Gieske, J

    1994-01-01

    This report identifies and describes emerging nondestructive inspection (NDI) methods that can potentially be used to inspect commercial transport and commuter aircraft for structural damage. The nine categories of emerging NDI techniques are: acoustic emission, x-ray computed tomography, backscatter radiation, reverse geometry x-ray, advanced electromagnetics, including magnetooptic imaging and advanced eddy current techniques, coherent optics, advanced ultrasonics, advanced visual, and infrared thermography. The physical principles, generalized performance characteristics, and typical applications associated with each method are described. In addition, aircraft inspection applications are discussed along with the associated technical considerations. Finally, the status of each technique is presented, with a discussion on when it may be available for use in actual aircraft maintenance programs. It should be noted that this is a companion document to DOT/FAA/CT-91/5, Current Nondestructive Inspection Methods for Aging Aircraft.

  1. Improved portable lighting for visual aircraft inspection

    SciTech Connect

    Shagam, R.N.; Lerner, J.; Shie, R.

    1995-04-01

    The most common tool used by aircraft inspectors is the personal flashlight. While it is compact and very portable, it is generally typified by poor beam quality which can interfere with the ability for an inspector to detect small defects and anomalies, such as cracks and corrosion sites, which may be indicators of major structural problems. A Light Shaping Diffuser{trademark} (LSD) installed in a stock flashlight as a replacement to the lens can improve the uniformity of an average flashlight and improve the quality of the inspection. Field trials at aircraft maintenance facilities have demonstrated general acceptance of the LSD by aircraft inspection and maintenance personnel.

  2. Improved portable lighting for visual aircraft inspection

    NASA Astrophysics Data System (ADS)

    Shagam, Richard N.; Lerner, Jeremy M.; Shie, Rick

    1995-07-01

    The most common tool used by aircraft inspectors is the personal flashlight. While it is compact and very portable, it is generally typified by poor beam quality which can interfere with the ability for an inspector to detect small defects and anomalies, such as cracks and corrosion sites, which may be indicators of major structural problems. A Light Shaping Diffuser TM (LSD) installed in a stock flashlight as a replacement to the lens can improve the uniformity of an average flashlight and improve the quality of the inspection. Field trials at aircraft maintenance facilities have demonstrated general acceptance of the LSD by aircraft inspection and maintenance personnel.

  3. 14 CFR 91.1109 - Aircraft maintenance: Inspection program.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false Aircraft maintenance: Inspection program... Ownership Operations Program Management § 91.1109 Aircraft maintenance: Inspection program. Each program manager must establish an aircraft inspection program for each make and model program aircraft and...

  4. Inspection of aging aircraft: A manufacturer's perspective

    NASA Technical Reports Server (NTRS)

    Hagemaier, Donald J.

    1992-01-01

    Douglas, in conjunction with operators and regulators, has established interrelated programs to identify and address issues regarding inspection of aging aircraft. These inspection programs consist of the following: Supplemental Inspection Documents; Corrosion Prevention and Control Documents; Repair Assessment Documents; and Service Bulletin Compliance Documents. In addition, airframe manufacturers perform extended airframe fatigue tests to deal with potential problems before they can develop in the fleet. Lastly, nondestructive inspection (NDI) plays a role in all these programs through the detection of cracks, corrosion, and disbonds. However, improved and more cost effective NDI methods are needed. Some methods such as magneto-optic imaging, electronic shearography, Diffractor-Sight, and multi-parameter eddy current testing appear viable for near-term improvements in NDI of aging aircraft.

  5. In-service inspection methods for graphite-epoxy structures on commercial transport aircraft

    NASA Technical Reports Server (NTRS)

    Phelps, M. L.

    1981-01-01

    In-service inspection methods for graphite-epoxy composite structures on commercial transport aircraft are determined. Graphite/epoxy structures, service incurred defects, current inspection practices and concerns of the airline and manufacturers, and other related information were determind by survey. Based on this information, applicable inspection nondestructive inspection methods are evaluated and inspection techniques determined. Technology is developed primarily in eddy current inspection.

  6. 14 CFR 91.415 - Changes to aircraft inspection programs.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 2 2013-01-01 2013-01-01 false Changes to aircraft inspection programs. 91..., Preventive Maintenance, and Alterations § 91.415 Changes to aircraft inspection programs. (a) Whenever the Administrator finds that revisions to an approved aircraft inspection program under § 91.409(f)(4) or §...

  7. 14 CFR 91.415 - Changes to aircraft inspection programs.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 2 2011-01-01 2011-01-01 false Changes to aircraft inspection programs. 91..., Preventive Maintenance, and Alterations § 91.415 Changes to aircraft inspection programs. (a) Whenever the Administrator finds that revisions to an approved aircraft inspection program under § 91.409(f)(4) or §...

  8. Monitoring Integrity Of Composite Aircraft Components

    NASA Technical Reports Server (NTRS)

    Tang, Shu Shing; Chen, Kuan-Luen; Kuo, An-Yu; Riccardella, Peter C.; Mucciardi, Anthony N.; Andrews, Robert J.; Grady, Joseph

    1994-01-01

    System developed that monitors integrity of composite-material structural components of aircraft in service. Includes strain gauges and accelerometers installed permanently in components to monitor vibrations, microprocessor-based data-acquisition system to process outputs of these vibration sensors, and desktop computer to analyze acquired data. By automating significant part of inspection process, system reduces amount of time needed for inspection and cost of inspection equipment. Contributes to safety by giving timely warning of hidden flaws that necessitate early, detailed inspection of critical components to determine whether components should be replaced immediately.

  9. 14 CFR 135.419 - Approved aircraft inspection program.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 3 2012-01-01 2012-01-01 false Approved aircraft inspection program. 135... OPERATING REQUIREMENTS: COMMUTER AND ON DEMAND OPERATIONS AND RULES GOVERNING PERSONS ON BOARD SUCH AIRCRAFT Maintenance, Preventive Maintenance, and Alterations § 135.419 Approved aircraft inspection program....

  10. 14 CFR 135.419 - Approved aircraft inspection program.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 3 2013-01-01 2013-01-01 false Approved aircraft inspection program. 135... OPERATING REQUIREMENTS: COMMUTER AND ON DEMAND OPERATIONS AND RULES GOVERNING PERSONS ON BOARD SUCH AIRCRAFT Maintenance, Preventive Maintenance, and Alterations § 135.419 Approved aircraft inspection program....

  11. 14 CFR 135.419 - Approved aircraft inspection program.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Approved aircraft inspection program. 135... OPERATING REQUIREMENTS: COMMUTER AND ON DEMAND OPERATIONS AND RULES GOVERNING PERSONS ON BOARD SUCH AIRCRAFT Maintenance, Preventive Maintenance, and Alterations § 135.419 Approved aircraft inspection program....

  12. Composite Lightning Rods for Aircraft

    NASA Technical Reports Server (NTRS)

    Bryan, Charles F., Jr.

    1986-01-01

    Composite, lightweight sacrificial tip with graphite designed reduces lightning-strike damage to composite parts of aircraft and dissipates harmful electrical energy. Device consists of slender composite rod fabricated from highly-conductive unidirectional reinforcing fibers in matrix material. Rods strategically installed in trailing edges of aircraft wings, tails, winglets, control surfaces, and rearward-most portion of aft fuselage.

  13. 14 CFR 91.1109 - Aircraft maintenance: Inspection program.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... Ownership Operations Program Management § 91.1109 Aircraft maintenance: Inspection program. Each program... thereof. (3) The name and address of the person responsible for scheduling the inspections required by...

  14. 14 CFR 91.1109 - Aircraft maintenance: Inspection program.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... Ownership Operations Program Management § 91.1109 Aircraft maintenance: Inspection program. Each program... thereof. (3) The name and address of the person responsible for scheduling the inspections required by...

  15. 14 CFR 91.1109 - Aircraft maintenance: Inspection program.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... Ownership Operations Program Management § 91.1109 Aircraft maintenance: Inspection program. Each program... thereof. (3) The name and address of the person responsible for scheduling the inspections required by...

  16. Potential of Computed Tomography for inspection of aircraft components

    SciTech Connect

    Azevedo, S.G.; Martz, H.E.; Schneberk, D.J.

    1993-08-01

    Computed Tomography (CT) using penetrating radiation (x- or gamma-rays) can be used in a number of aircraft applications. This technique results in 3D volumetric attenuation data that is related to density and effective atomic number. CT is a transmission scanning method that must allow complete access to both sides of the object under inspection; the radiation source and detection systems must surround the object. This normally precludes the inspection of some large or planar (large aspect ratio) parts of the aircraft. However, we are pursuing recent limited-data techniques using object model information to obtain useful data from the partial information acquired. As illustrative examples, we describe how CT was instrumental in the analysis of particular aircraft components. These include fuselage panels, single crystal turbine blades, and aluminumlithium composites. These tests were performed by the members of the Nondestructive Evaluation Section at the Lawrence Livermore National Laboratory (LLNL) where we have been actively working in CT research and development. The aerospace applications can represent various phases of the design, manufacture, assembly, test, and retirement of various components and assemblies.

  17. Light shaping diffusers{trademark} improve aircraft inspection

    SciTech Connect

    Shagam, R.N.; Shie, R.; Lerner, J.

    1994-11-01

    Physical Optical Corporation has introduced a Light Shaping Diffuser{trademark} (LSD) for the specialized illumination requirements of aircraft inspection. Attached to a handheld, battery-powered flashlight, this light-weight, holographic diffuser element provides bright, even illumination as aircraft inspectors perform the important task of visually examining aircraft for possible structural defects. Field trials conducted by the Aging Aircraft Program at Sandia National Laboratories confirm that the LSD-equipped flashlights are preferred by visual inspectors over stock flashlights.

  18. Dynamic thermal tomography for nondestructive inspection of aging aircraft

    SciTech Connect

    Del Grande, N.K.; Dolan, K.W.; Durbin, P.F.; Gorvad, M.R.; Shapiro, A.B.

    1993-11-01

    The authors apply dual-band infrared (DBIR) imaging as a dynamic thermal tomography tool for wide area inspection of a Boeing 737 aircraft and several Boeing KC-135 aircraft panels. The analyses are discussed in this report. After flash-heating the aircraft skin, they record synchronized DBIR images every 40 ms, from onset to 8 seconds after the heat flash. They analyze selective DBIR image ratios which enhance surface temperature contrast and remove surface-emissivity clutter. The Boeing 737 and KC-135 aircraft fuselage panels have varying percent thickness losses from corrosion. They established the correlation of percent thickness loss with surface temperature rise (above ambient) for a partially corroded F-18 wing box structure and several aluminum plates which had 6 to 60% thickness losses at milled flat-bottom hole sites. Based on this correlation, lap splice temperatures rise 1C per 24 {plus_minus} 5% material loss at 0.4 s after the heat flash. They tabulate and map corrosion-related percent thickness loss effects for the riveted Boeing 737, and the riveted Boeing KKC-135. They map the fuselage composite thermal inertia, based on the (inverse) slope of the surface temperature versus inverse square root of time. Composite thermal inertia maps characterized shallow skin defects within the lap splice at early times (< 0.3 s) and deeper skin defects within the lap splice at late times (> 0.4 s). Late time composite thermal inertia maps depict where corrosion-related thickness losses occur (e.g., on the inside of the Boeing 737 lap splice, beneath the galley and the latrine). Lap splice sites on a typical Boeing KC-135 panel with low composite thermal inertia values had high skin-thickness losses from corrosion.

  19. Advanced technology composite aircraft structures

    NASA Technical Reports Server (NTRS)

    Ilcewicz, Larry B.; Walker, Thomas H.

    1991-01-01

    Work performed during the 25th month on NAS1-18889, Advanced Technology Composite Aircraft Structures, is summarized. The main objective of this program is to develop an integrated technology and demonstrate a confidence level that permits the cost- and weight-effective use of advanced composite materials in primary structures of future aircraft with the emphasis on pressurized fuselages. The period from 1-31 May 1991 is covered.

  20. Using alternative feedback strategies to improve aircraft inspection performance

    NASA Astrophysics Data System (ADS)

    Kaewkuekool, Sittichai

    The aircraft inspection and maintenance system consists of several interrelated human and machine components, with visual inspection playing a significant role in ensuring aircraft safety. Training has been identified as one of the most important intervention strategies for enhancing the quality and reliability of aircraft inspection. This process has the potential to be improved using advancements in computer technology, especially virtual reality (VR) technology, which is becoming increasingly more affordable and prevalent. In light of this situation, this study investigated the use of VR technology to support training in the improvement of aircraft inspection performance. An experiment was developed to investigate the use of performance and process feedback in both statistical and graphical forms in two different task environments. In addition, information on defect criticality, defect location, and occurrence of defect was provided to subjects to study the effectiveness of feedforward information on inspection performance. Specifically, the experiment involved the inspection of an aircraft cargo bay using VR technology with eye tracking movement devices and a 6 degree of freedom mouse for pointing and clicking on defects. Results from the feedback training indicated that providing process along with performance feedback improved inspection performance as evidenced in the speed, accuracy and search strategy measures. Similar results were shown for both task environments. However, the addition feedforward information in the heterogeneous task environment yielded ever better inspection performance, and process and performance feedback coupled with feedforward information on defect criticality, defect location, and occurrence of defect yielded the best inspection performance as seen in the speed, accuracy and search strategy measures. The findings of this study indicate that using a combination of training intervention strategies leads to an improvement in

  1. Composite structural materials. [aircraft applications

    NASA Technical Reports Server (NTRS)

    Ansell, G. S.; Loewy, R. G.; Wiberley, S. E.

    1981-01-01

    The development of composite materials for aircraft applications is addressed with specific consideration of physical properties, structural concepts and analysis, manufacturing, reliability, and life prediction. The design and flight testing of composite ultralight gliders is documented. Advances in computer aided design and methods for nondestructive testing are also discussed.

  2. Commercial transport aircraft composite structures

    NASA Technical Reports Server (NTRS)

    Mccarty, J. E.

    1983-01-01

    The role that analysis plays in the development, production, and substantiation of aircraft structures is discussed. The types, elements, and applications of failure that are used and needed; the current application of analysis methods to commercial aircraft advanced composite structures, along with a projection of future needs; and some personal thoughts on analysis development goals and the elements of an approach to analysis development are discussed.

  3. Impact analysis of composite aircraft structures

    NASA Technical Reports Server (NTRS)

    Pifko, Allan B.; Kushner, Alan S.

    1993-01-01

    The impact analysis of composite aircraft structures is discussed. Topics discussed include: background remarks on aircraft crashworthiness; comments on modeling strategies for crashworthiness simulation; initial study of simulation of progressive failure of an aircraft component constructed of composite material; and research direction in composite characterization for impact analysis.

  4. Composite structural materials. [aircraft structures

    NASA Technical Reports Server (NTRS)

    Ansell, G. S.; Loewy, R. G.; Wiberley, S. E.

    1980-01-01

    The use of filamentary composite materials in the design and construction of primary aircraft structures is considered with emphasis on efforts to develop advanced technology in the areas of physical properties, structural concepts and analysis, manufacturing, and reliability and life prediction. The redesign of a main spar/rib region on the Boeing 727 elevator near its actuator attachment point is discussed. A composite fabrication and test facility is described as well as the use of minicomputers for computer aided design. Other topics covered include (1) advanced structural analysis methids for composites; (2) ultrasonic nondestructive testing of composite structures; (3) optimum combination of hardeners in the cure of epoxy; (4) fatigue in composite materials; (5) resin matrix characterization and properties; (6) postbuckling analysis of curved laminate composite panels; and (7) acoustic emission testing of composite tensile specimens.

  5. Industrial applications of shearography for inspection of aircraft components

    NASA Astrophysics Data System (ADS)

    Krupka, Rene; Walz, Thomas; Ettemeyer, Andreas

    2005-04-01

    Shearography has been validated as fast and reliable inspection technique for aerospace components. Following several years phase of evaluation of the technique, meanwhile, shearography has entered the industrial production inspection. The applications basically range from serial inspection in the production line to field inspection in assembly and to applications in the maintenance and repair area. In all applications, the main advantages of shearography, as very fast and full field insection and high sensitivity even on very complex on composite materials have led to the decision for laser shearography as inspection tool. In this paper, we present some highlights of industrial shearography inspection. One of the first industrial installations of laser shearography in Europe was a fully automatic inspection system for helicopter rotorblades. Complete rotor blades are inspected within 10 minutes on delaminations and debondingg in the composite structure. In case of more complex components, robotic manipulation of the shearography camera has proven to be the optimal solution. An industry 6-axis robot give utmost flexibility to position the camera in any angle and distance. Automatic defect marking systems have also been introduced to indicate the exact position of the defect directly on the inspected component. Other applications are shearography inspection systems for abradable seals in jet engines and portable shearography inspection systems for maintenance and repair inspection in the field. In this paper, recent installations of automatice inspection systems in aerospace industries are presented.

  6. Industrial applications of shearography for inspections of aircraft components

    NASA Astrophysics Data System (ADS)

    Krupka, Rene; Waltz, T.; Ettemeyer, Andreas

    2003-05-01

    Shearography has been validated as fast and reliable inspection technique for aerospace components. Following several years phase of evaluation of the technique, meanwhile, shearography has entered the industrial production inspection. The applications basically range from serial inspection in the production line to field inspection in assembly and to applications in the maintenance and repair area. In all applications, the main advantages of shearography, as very fast and full field inspection and high sensitivity even on very complex composite materials have led to the decision for laser shearography as inspection tool. In this paper, we present examples of recent industrial shearography inspection systems in the field of aerospace. One of the first industrial installations of laser shearography in Europe was a fully automatic inspection system for helicopter rotorblades. Complete rotor blades are inspected within 10 minutes on delaminations and debondings in the composite structure. In case of more complex components, robotic manipulation of the shearography camera has proven to be the optimum solution. An industry 6-axis robot gives utmost flexibility to position the camera in any angle and distance. Automatic defect marking systems have also been introduced to indicate the exact position of the defect directly on the inspected component. Other applications cover the inspection of abradable seals in jet engines and portable shearography inspection systems for maintenance and repair inspection in the field.

  7. 14 CFR 135.419 - Approved aircraft inspection program.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 3 2011-01-01 2011-01-01 false Approved aircraft inspection program. 135.419 Section 135.419 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIR CARRIERS AND OPERATORS FOR COMPENSATION OR HIRE: CERTIFICATION AND...

  8. 14 CFR 91.1109 - Aircraft maintenance: Inspection program.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 2 2012-01-01 2012-01-01 false Aircraft maintenance: Inspection program. 91.1109 Section 91.1109 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIR TRAFFIC AND GENERAL OPERATING RULES GENERAL OPERATING AND FLIGHT RULES Fractional Ownership Operations Program Management...

  9. 14 CFR 135.419 - Approved aircraft inspection program.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 3 2014-01-01 2014-01-01 false Approved aircraft inspection program. 135.419 Section 135.419 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... chapter are not adequate to meet this part, or upon application by a certificate holder, the...

  10. NASA service experience with composite components. [for aircraft structures

    NASA Technical Reports Server (NTRS)

    Dexter, H. B.; Chapman, A. J.

    1980-01-01

    NASA Langley has been active in sponsoring flight service programs with advanced composites during the past decade. A broad data base and confidence in the durability of composite structures are being developed. Flight service experience is reported for more than 140 composite aircraft components with up to 8 years service and almost two million successful component flight hours. Composite components are being evaluated on Boeing, Douglas, and Lockheed transport aircraft. Components are currently under development for service evaluation on Bell and Sikorsky helicopters. Design concepts and inspection and maintenance results are reported for components currently in service. Components under development in the NASA Aircraft Energy Efficiency (ACEE) program are discussed. Results of flight, outdoor ground, and controlled laboratory environmental tests on composite materials used in the flight service programs are also presented.

  11. Dual-band infrared imaging applications: Locating buried minefields, mapping sea ice, and inspecting aging aircraft

    SciTech Connect

    Del Grande, N.K.; Durbin, P.F.; Perkins, D.E.

    1992-09-01

    We discuss the use of dual-band infrared (DBIR) imaging for three quantitative NDE applications: location buried surrogate mines, mapping sea ice thicknesses and inspecting subsurface flaws in aging aircraft parts. Our system of DBIR imaging offers a unique combination of thermal resolution, detectability, and interpretability. Pioneered at Lawrence Livermore Laboratory, it resolves 0.2 {degrees}C differences in surface temperatures needed to identify buried mine sites and distinguish them from surface features. It produces both surface temperature and emissivity-ratio images of sea ice, needed to accurately map ice thicknesses (e.g., by first removing clutter due to snow and surface roughness effects). The DBIR imaging technique depicts subsurface flaws in composite patches and lap joints of aircraft, thus providing a needed tool for aging aircraft inspections.

  12. Low-voltage radiography on aircraft composite doublers

    SciTech Connect

    Moore, D.G.; Murray, J.D.

    1997-11-01

    Composite doublers are gaining popularity for their ability to repair and reinforce commercial aircraft structures and it is anticipated that the potential cost savings may spur wider use of this technology. But before composite doublers can be accepted by the civil aviation industry, inspection techniques must be developed to verify the integrity of the doubler and the parent material under the doubler. The Federal Aviation Administration Airworthiness Assurance NDI Validation Center (AANC) is currently developing test methods to inspect aircraft structures under composite doublers using low kilovoltage radiography. This paper documents the radiographic techniques developed by the AANC which have been found to give the best contrast of the radiographic image with reduced image distortion.

  13. Development of Nondestructive Inspection Methods for Composite Repair

    NASA Astrophysics Data System (ADS)

    Hsu, D. K.; Barnard, D. J.; Peters, J. J.; Dayal, V.

    2003-03-01

    This paper describes the development and implementation of two complementary nondestructive inspection methods for repairs made on aircraft composite honeycomb structures: computer aided tap testing (CATT) and air-coupled ultrasonic testing (AC-UT). The CATT, being a semi-automated and quantitative technique, is exploited to map out the interior conditions of a repaired part. The same repair is also imaged with air-coupled ultrasound and both compared with the results from destructive sectioning.

  14. Dynamic thermal tomography for nondestructive inspection of aging aircraft

    NASA Astrophysics Data System (ADS)

    Del Grande, Nancy K.; Dolan, Kenneth W.; Durbin, Philip F.; Gorvad, Michael R.; Shapiro, Arthur B.

    1993-12-01

    We apply dual-band infrared (DBIR) imaging as a dynamic thermal tomography tool for wide area inspection of a Boeing 737 aircraft (owned by the FAA/AANC at the Sandia hangar in Albuquerque, NM) and several Boeing KC-135 aircraft panels (used for the round robin experiment conducted at Tinker AFB, OK). Our analyses are discussed in this report. After flash-heating the aircraft skin, we record synchronized DBIR images every 40 ms, from onset to 8 seconds after the heat flash. We analyze selective DBIR image ratios which enhance surface temperature contrast and remove surface-emissivity clutter (from dirt, dents, tape, markings, ink, sealants, uneven paint, paint stripper, exposed metal and roughness variations). The Boeing 737 and KC-135 aircraft fuselage panels have varying percent thickness losses from corrosion. We established the correlation of percent thickness loss with surface temperature rise (above ambient) for a partially corroded F-18 wing box structure (with a 2.9 mm uncorroded thickness) and several aluminum plates (with 1.0, 1.1, 2.3, and 3.9 mm thicknesses) which had 6 to 60% thickness losses at milled flat-bottom hole sites.

  15. Eddy current inspection of bonded composite crack repair

    NASA Astrophysics Data System (ADS)

    Smith, Thomas K., Jr.; Guijt, Cornelius; Fredell, Robert

    1996-11-01

    The aging of the US aircraft fleet poses serious economic and safety challenges. Fatigue cracks in the 7079-T6 aluminum fuselage skin of aging transports have presented zn opportunity to test a prototype repair. GLARE, a fiber metal laminate, has been applied to repair fuselage cracks in the fuselage skin of a US transport aircraft. This affordable prototype solution to extend the life of aging aircraft requires an inspection method to track crack growth and monitor the effectiveness of the patch on repaired fuselage skin. The fiber metal laminate patch is opaque and the fuselage skin at the damage location generally can only be accessed from the outside surface requiring the use of a non-destructive means to monitor crack length. Advances in eddy current inspection technology have provided a means to detect and track crack growth beneath patches on fuselage skins. This paper describes the development of low-frequency eddy current techniques to monitor cracks under bonded composite repair patches applied to stiffened fuselage structures. The development involved the use of a rugged portable eddy current inspection unit. The results show crack growth can be monitored to ensure the continued structural integrity of repaired flawed structures; however, the influence of substructure present a challenge to the inspector in detecting crack growth.

  16. Durability of commercial aircraft and helicopter composite structures

    NASA Technical Reports Server (NTRS)

    Dexter, H. B.

    1982-01-01

    The development of advanced composite technology during the past decade is discussed. Both secondary and primary components fabricated with boron, graphite, and Kevlar composites are evaluated. Included are spoilers, rudders, and fairings on commercial transports, boron/epoxy reinforced wing structure on C-130 military transports, and doors, fairings, tail rotors, vertical fins, and horizontal stabilizers on commercial helicopters. The development of composite structures resulted in advances in design and manufacturing technology for secondary and primary composite structures for commercial transports. Design concepts and inspection and maintenance results for the components in service are reported. The flight, outdoor ground, and controlled laboratory environmental effects on composites were also determined. Effects of moisture absorption, ultraviolet radiation, aircraft fuels and fluids, and sustained tensile stress are included. Critical parameters affecting the long term durability of composite materials are identified.

  17. Aging aircraft NDI Development and Demonstration Center (AANC): An overview. [nondestructive inspection

    NASA Technical Reports Server (NTRS)

    Walter, Patrick L.

    1992-01-01

    A major center with emphasis on validation of nondestructive inspection (NDI) techniques for aging aircraft, the Aging Aircraft NDI Development and Demonstration Center (AANC), has been funded by the FAA at Sandia National Laboratories. The Center has been assigned specific tasks in developing techniques for the nondestructive inspection of static engine parts, assessing inspection reliability (POD experiments), developing testbeds for NDI validation, maintaining a FAA library of characterized aircraft structural test specimens, and leasing a hangar to house a high flight cycle transport aircraft for use as a full scale test bed.

  18. NUVU: handheld instruments for video inspection of aircraft wiring

    NASA Astrophysics Data System (ADS)

    Pike, John N.; Mehrotra, Yogesh; Kaplan, Herbert

    1999-01-01

    Most of the current practices of manual visual inspection of aircraft wiring bundles can be replaced or assisted by a portable test system consisting of a miniature B/W or color TV camera and controllable uniform illumination mounted in a flashlight-sized, hand-held unit weighing less than one pound. The location and configuration of the battery power supply and image viewing and storage means are at the discretion of the inspector. A typical viewed area is nominally 1 inch by 1.3 inches, with a depth of field up to 1.5 inches. Tradeoffs among pixel dimensions, geometrical optics, and lens diffraction which arise in the design of such a unit are discussed. Data are presented showing actuator measured depths of field and image resolutions vs. variable camera lens aperture under real conditions. The image size in these tests provided an overall 12X enlargement of the target, as viewed by the inspector in real time. On insulated wires as small as 1mm OD, printed markings are easily seen and read, as are common chafes, radial surface cracks, and other surface anomalies of the insulation. The present mechanical design permits the small unit not only to inspect areas in any direction to which the hand and wrist can point, but also allows insertion of the unit in areas not easily accessible to the hand or eye.

  19. Dual-band infrared (DBIR) imaging inspections of Boeing 737 and KC-135 aircraft panels

    SciTech Connect

    Del Grande, N.K.; Dolan, K.W.; Durbin, P.F.; Gorvad, M.R.; Shapiro, A.B.

    1993-08-27

    We apply dual-band infrared (DBIR) imaging as a dynamic thermal tomography tool for wide area inspection of a Boeing 737 aircraft, and several Boeing KC-135 aircraft panels. Our analyses are discussed in this report. After flash-heating the aircraft skin, we record synchronized DBIR images every 40 ms, from onset to 8 seconds after the heat flash. We analyze selective DBIR image ratios which enhance surface temperature contrast and remove surface-emissivity clutter (from dirt, dents, tape, markings, ink, sealants, uneven paint, paint stripper, exposed metal and roughness variations). The Boeing 737 and KC-135 aircraft fuselage panels have varying percent thickness losses from corrosion. We established the correlation of percent thickness loss with surface temperature rise (above ambient) for a partially corroded F-18 wing box structure and several aluminum reference panels. Based on this correlation, lap splice temperatures rise 1{degrees}C per 24 {plus_minus} 5 % material loss at 0.4 s after the heat flash. We show tables, charts and temperature maps of typical lap splice material losses for the riveted (and bonded) Boeing 737, and the riveted (but unbonded) Boeing KC-135. We map the fuselage composite thermal inertia, based on the (inverse) slope of the surface temperature versus inverse square root of time. Composite thermal inertia maps characterize shallow skin defects within the lap splice at early times (<0.3 s) and deeper skin defects within the lap splice at late times (>0.4 s). Late time composite thermal inertia maps depict where corrosion-related thickness losses occur. Lap splice sites on a typical Boeing KC-135 panel with low composite thermal inertia values had high skin-thickness losses from corrosion.

  20. Thermal Inspection of Composite Honeycomb Structures

    NASA Technical Reports Server (NTRS)

    Zalameda, Joseph N.; Parker, F. Raymond

    2014-01-01

    Composite honeycomb structures continue to be widely used in aerospace applications due to their low weight and high strength advantages. Developing nondestructive evaluation (NDE) inspection methods are essential for their safe performance. Pulsed thermography is a commonly used technique for composite honeycomb structure inspections due to its large area and rapid inspection capability. Pulsed thermography is shown to be sensitive for detection of face sheet impact damage and face sheet to core disbond. Data processing techniques, using principal component analysis to improve the defect contrast, are presented. In addition, limitations to the thermal detection of the core are investigated. Other NDE techniques, such as computed tomography X-ray and ultrasound, are used for comparison to the thermography results.

  1. Thermal inspection of composite honeycomb structures

    NASA Astrophysics Data System (ADS)

    Zalameda, Joseph N.; Parker, F. Raymond

    2014-05-01

    Composite honeycomb structures continue to be widely used in aerospace applications due to their low weight and high strength advantages. Developing nondestructive evaluation (NDE) inspection methods are essential for their safe performance. Pulsed thermography is a commonly used technique for composite honeycomb structure inspections due to its large area and rapid inspection capability. Pulsed thermography is shown to be sensitive for detection of face sheet impact damage and face sheet to core disbond. Data processing techniques, using principal component analysis to improve the defect contrast, are presented. In addition, limitations to the thermal detection of the core are investigated. Other NDE techniques, such as computed tomography X-ray and ultrasound, are used for comparison to the thermography results.

  2. Environmental effects on composites for aircraft

    NASA Technical Reports Server (NTRS)

    Pride, R. A.

    1978-01-01

    The influence of the operational environment on the behavior of composite materials and aircraft components fabricated with these composite materials was considered. Structural weight savings, manufacturing cost savings, and long-term environmental durability are among the factors examined. The flight service experience to date of composite components is evaluated. In addition, the influence of a number of worldwide, ground based outdoor exposures on the physical and mechanical properties of six composite materials is discussed. In particular, the current extent of the ultraviolet surface degradation and the moisture gained by diffusion is shown.

  3. Performance analysis of bonded composite doublers on aircraft structures

    SciTech Connect

    Roach, D.

    1995-08-01

    Researchers contend that composite repairs (or structural reinforcement doublers) offer numerous advantages over metallic patches including corrosion resistance, light weight, high strength, elimination of rivets, and time savings in installation. Their use in commercial aviation has been stifled by uncertainties surrounding their application, subsequent inspection and long-term endurance. The process of repairing or reinforcing airplane structures is time consuming and the design is dependent upon an accompanying stress and fatigue analysis. A repair that is too stiff may result in a loss of fatigue life, continued growth of the crack being repaired, and the initiation of a new flaw in the undesirable high stress field around the patch. Uncertainties in load spectrums used to design repairs exacerbates these problems as does the use of rivets to apply conventional doublers. Many of these repair or structural reinforcement difficulties can be addressed through the use of composite doublers. Primary among unknown entities are the effects of non-optimum installations and the certification of adequate inspection procedures. This paper presents on overview of a program intended to introduce composite doubler technology to the US commercial aircraft fleet. In this project, a specific composite application has been chosen on an L-1011 aircraft in order to focus the tasks on application and operation issues. Through the use of laboratory test structures and flight demonstrations on an in-service L-1011 airplane, this study is investigating composite doubler design, fabrication, installation, structural integrity, and non-destructive evaluation. In addition to providing an overview of the L-1011 project, this paper focuses on a series of fatigue and strength tests which have been conducted in order to study the damage tolerance of composite doublers. Test results to-date are presented.

  4. Environmental effects on composites for aircraft

    NASA Technical Reports Server (NTRS)

    Pride, R. A.

    1978-01-01

    A number of ongoing, long-term environmental effects programs for composite materials are evaluated. The flight service experience was evaluated for 142 composite aircraft components after more than 5 years and 1 million successful component flight hours. Ground-based outdoor exposures of composite material coupons after 3 years of exposure at 5 sites have reached equilibrium levels of moisture pickup which are predictable. Solar ultraviolet-induced material loss is discussed for these same exposures. No significant degradation was observed in residual strength for either stressed or unstressed specimens, or for exposures to aviation fuels and fluids.

  5. Service evaluation of aircraft composite structural components

    NASA Technical Reports Server (NTRS)

    Brooks, W. A., Jr.; Dow, M. B.

    1973-01-01

    The advantages of the use of composite materials in structural applications have been identified in numerous engineering studies. Technology development programs are underway to correct known deficiencies and to provide needed improvements. However, in the final analysis, flight service programs are necessary to develop broader acceptance of, and confidence in, any new class of materials such as composites. Such flight programs, initiated by NASA Langley Research Center, are reviewed. These programs which include the selectively reinforced metal and the all-composite concepts applied to both secondary and primary aircraft structural components, are described and current status is indicated.

  6. Metal matrix composites for aircraft propulsion systems

    NASA Technical Reports Server (NTRS)

    Signorelli, R. A.

    1975-01-01

    Studies of advanced aircraft propulsion systems have indicated that performance gains and operating costs are possible through the application of metal matrix composites. Compressor fan blades and turbine blades have been identified as components with high payoff potential as a result of these studies. This paper will present the current status of development of five candidate materials for such applications. Boron fiber/aluminum, boron fiber/titanium, and silicon carbide fiber/titanium composites are considered for lightweight compressor fan blades. Directionally solidified eutectic superalloy and tungsten wire/superalloy composites are considered for application to turbine blades for use temperatures to 1100 C (2000 F).

  7. Experimental flight test vibration measurements and nondestructive inspection on a USCG HC-130H aircraft

    SciTech Connect

    Moore, D.G.; Jones, C.R.; Mihelic, J.E.; Barnes, J.D.

    1998-08-01

    This paper presents results of experimental flight test vibration measurements and structural inspections performed by the Federal Aviation Administration`s Airworthiness Assurance NDI Validation Center (AANC) at Sandia National Laboratories and the US Coast Guard Aircraft Repair and Supply Center (ARSC). Structural and aerodynamic changes induced by mounting a Forward Looking Infrared (FLIR) system on a USCG HC-130H aircraft are described. The FLIR adversely affected the air flow characteristics and structural vibration on the external skin of the aircraft`s right main wheel well fairing. Upon initial discovery of skin cracking and visual observation of skin vibration in flight by the FLIR, a baseline flight without the FLIR was conducted and compared to other measurements with the FLIR installed. Nondestructive inspection procedures were developed to detect cracks in the skin and supporting structural elements and document the initial structural condition of the aircraft. Inspection results and flight test vibration data revealed that the FLIR created higher than expected flight loading and was the possible source of the skin cracking. The Coast Guard performed significant structural repair and enhancement on this aircraft, and additional in-flight vibration measurements were collected on the strengthened area both with and without the FLIR installed. After three months of further operational FLIR usage, the new aircraft skin with the enhanced structural modification was reinspected and found to be free of flaws. Additional US Coast Guard HC-130H aircraft are now being similarly modified to accommodate this FLIR system. Measurements of in-flight vibration levels with and without the FLIR installed, and both before and after the structural enhancement and repair were conducted on the skin and supporting structure in the aircraft`s right main wheel fairing. Inspection results and techniques developed to verify the aircraft`s structural integrity are discussed.

  8. Fibre reinforced composites in aircraft construction

    NASA Astrophysics Data System (ADS)

    Soutis, C.

    2005-02-01

    Fibrous composites have found applications in aircraft from the first flight of the Wright Brothers’ Flyer 1, in North Carolina on December 17, 1903, to the plethora of uses now enjoyed by them on both military and civil aircrafts, in addition to more exotic applications on unmanned aerial vehicles (UAVs), space launchers and satellites. Their growing use has risen from their high specific strength and stiffness, when compared to the more conventional materials, and the ability to shape and tailor their structure to produce more aerodynamically efficient structural configurations. In this paper, a review of recent advances using composites in modern aircraft construction is presented and it is argued that fibre reinforced polymers, especially carbon fibre reinforced plastics (CFRP) can and will in the future contribute more than 50% of the structural mass of an aircraft. However, affordability is the key to survival in aerospace manufacturing, whether civil or military, and therefore effort should be devoted to analysis and computational simulation of the manufacturing and assembly process as well as the simulation of the performance of the structure, since they are intimately connected.

  9. Advanced composite fiber/metal pressure vessels for aircraft applications

    NASA Astrophysics Data System (ADS)

    Papanicolopoulos, Aleck

    1993-06-01

    Structural Composites Industries has developed, qualified, and delivered a number of high performance carbon epoxy overwrapped/seamless aluminum liner pressure vessels for use in military aircraft where low weight, low cost, high operating pressure and short lead time are the primary considerations. This paper describes product design, development, and qualification for a typical program. The vessel requirements included a munitions insensitivity criterion as evidenced by no fragmentation following impact by a .50 cal tumbling bullet. This was met by the development of a carbon-Spectra hybrid composite overwrap on a thin-walled seamless aluminum liner. The same manufacturing, inspection, and test processes that are used to produce lightweight, thin walled seamless aluminum lined carbon/epoxy overwrapped pressure vessels for satellite and other space applications were used to fabricate this vessel. This report focuses on the results of performance in the qualification testing.

  10. Nondestructive monitoring of aircraft composites using terahertz radiation

    NASA Astrophysics Data System (ADS)

    Balbekin, Nikolay S.; Novoselov, Evgenii V.; Pavlov, Pavel V.; Bespalov, Victor G.; Petrov, Nikolay V.

    2015-03-01

    In this paper we consider using the terahertz (THz) time domain spectroscopy (TDS) for non destructive testing and determining the chemical composition of the vanes and rotor-blade spars. A versatile terahertz spectrometer for reflection and transmission has been used for experiments. We consider the features of measured terahertz signal in temporal and spectral domains during propagation through and reflecting from various defects in investigated objects, such as voids and foliation. We discuss requirements are applicable to the setup and are necessary to produce an image of these defects, such as signal-to-noise ratio and a method for registration THz radiation. Obtained results indicated the prospects of the THz TDS method for the inspection of defects and determination of the particularities of chemical composition of aircraft parts.

  11. Nondestructive inspection of a composite missile launcher

    NASA Astrophysics Data System (ADS)

    Ley, O.; Chung, S.; Butera, M.; Valatka, T.; Triplett, M. H.; Godinez, V.

    2012-05-01

    Lighter weight alternatives are being sought to replace metallic components currently used in high performance aviation and missile systems. Benefits of lightweight, high strength carbon fiber reinforced composites in missile launchers and rocket motor cases include improved fuel economy, increased flight times, enhanced lethality and/or increased velocity. In this work, various nondestructive inspection techniques are investigated for the damage assessment of a composite missile launcher system for use in U.S. Army attack helicopters. The launcher system, which includes rails and a hardback, can be subject to impact damage from accidental tool drops, routine operation, and/or ballistic threats. The composite hardback and the launch rails both have complex geometries that can challenge the inspection process. Scanning techniques such as line scanning thermography, ultrasonic, and acousto-ultrasonics will be used and compared to determine damage detection accuracy, reliability, and efficiency. Results will also be compared with visual observations to determine if there is a correlation. The goal is to establish an inspection method that quickly and accurately assesses damage extent in order to minimize service time and return the missile system back into the field [1].

  12. NASA Thermographic Inspection of Advanced Composite Materials

    NASA Technical Reports Server (NTRS)

    Cramer, K. Elliott

    2004-01-01

    As the use of advanced composite materials continues to increase in the aerospace community, the need for a quantitative, rapid, in situ inspection technology has become a critical concern throughout the industry. In many applications it is necessary to monitor changes in these materials over an extended period of time to determine the effects of various load conditions. Additionally, the detection and characterization of defects such as delaminations, is of great concern. This paper will present the application of infrared thermography to characterize various composite materials and show the advantages of different heat source types. Finally, various analysis methodologies used for quantitative material property characterization will be discussed.

  13. Millimeter Wave Holographical Inspection of Honeycomb Composites

    NASA Technical Reports Server (NTRS)

    Case, J. T.; Kharkovsky, S.; Zoughi, R.; Stefes, G.; Hepburn, Frank L.; Hepburn, Frank L.

    2007-01-01

    Multi-layered composite structures manufactured with honeycomb, foam or balsa wood cores are finding increasing utility in a variety of aerospace, transportation, and infrastructure applications. Due to the low conductivity and inhomogeneity associated with these composites standard nondestructive testing (NDT) methods are not always capable of inspecting their interior for various defects caused during the manufacturing process or as a result of in-service loading. On the contrary, microwave and millimeter wave NDT methods are well-suited for inspecting these structures since signals at these frequencies readily penetrate through these structures and reflect from different interior boundaries revealing the presence of a wide range of defects such as disbond, delamination, moisture and oil intrusion, impact damage, etc. Millimeter wave frequency spectrum spans 30 GHz - 300 GHz with corresponding wavelengths of 10 - 1 mm. Due to the inherent short wavelengths at these frequencies, one can produce high spatial resolution images of these composites either using real-antenna focused or synthetic-aperture focused methods. In addition, incorporation of swept-frequency in the latter method (i.e., holography) results in high-resolution three-dimensional images. This paper presents the basic steps behind producing such images at millimeter wave frequencies and the results of two honeycomb composite panels are demonstrated at Q-band (33-50 GHz). In addition, these results are compared to previous results using X-ray computed tomography.

  14. The impact of instructions on aircraft visual inspection performance : a first look at the overall results.

    SciTech Connect

    Drury, Colin G.; Spencer, Floyd Wayne; Wenner, Caren A.

    2003-07-01

    The purpose of this study was to investigate the impact of instructions on aircraft visual inspection performance and strategy. Forty-two inspectors from industry were asked to perform inspections of six areas of a Boeing 737. Six different instruction versions were developed for each inspection task, varying in the number and type of directed inspections. The amount of time spent inspecting, the number of calls made, and the number of the feedback calls detected all varied widely across the inspectors. However, inspectors who used instructions with a higher number of directed inspections referred to the instructions more often during and after the task, and found a higher percentage of a selected set of feedback cracks than inspectors using other instruction versions. This suggests that specific instructions can help overall inspection performance, not just performance on the defects specified. Further, instructions were shown to change the way an inspector approaches a task.

  15. Using virtual reality technology for aircraft visual inspection training: presence and comparison studies.

    PubMed

    Vora, Jeenal; Nair, Santosh; Gramopadhye, Anand K; Duchowski, Andrew T; Melloy, Brian J; Kanki, Barbara

    2002-11-01

    The aircraft maintenance industry is a complex system consisting of several interrelated human and machine components. Recognizing this, the Federal Aviation Administration (FAA) has pursued human factors related research. In the maintenance arena the research has focused on the aircraft inspection process and the aircraft inspector. Training has been identified as the primary intervention strategy to improve the quality and reliability of aircraft inspection. If training is to be successful, it is critical that we provide aircraft inspectors with appropriate training tools and environment. In response to this need, the paper outlines the development of a virtual reality (VR) system for aircraft inspection training. VR has generated much excitement but little formal proof that it is useful. However, since VR interfaces are difficult and expensive to build, the computer graphics community needs to be able to predict which applications will benefit from VR. To address this important issue, this research measured the degree of immersion and presence felt by subjects in a virtual environment simulator. Specifically, it conducted two controlled studies using the VR system developed for visual inspection task of an aft-cargo bay at the VR Lab of Clemson University. Beyond assembling the visual inspection virtual environment, a significant goal of this project was to explore subjective presence as it affects task performance. The results of this study indicated that the system scored high on the issues related to the degree of presence felt by the subjects. As a next logical step, this study, then, compared VR to an existing PC-based aircraft inspection simulator. The results showed that the VR system was better and preferred over the PC-based training tool. PMID:12507340

  16. Experimental flight test vibration measurements and nondestructive inspection on a USCG HC-130H aircraft

    NASA Technical Reports Server (NTRS)

    Moore, D. G.; Jones, C. R.; Mihelic, J. E.; Barnes, J. D.

    1998-01-01

    This paper presents results of experimental flight test vibration measurements and structural inspections performed by the Federal Aviation Administration's Airworthiness Assurance NDI Validation Center (AANC) at Sandia National Laboratories and the US Coast Guard Aircraft Repair and Supply Center (ARSC). Structural and aerodynamic changes induced by mounting a Forward Looking Infrared (FLIR) system on a USCG HC-130H aircraft are described. The FLIR adversely affected the air flow characteristics and structural vibration on the external skin of the aircraft's right main wheel well fairing. Upon initial discovery of skin cracking and visual observation of skin vibration in flight by the FLIR, a baseline flight without the FLIR was conducted and compared to other measurements with the FLIR installed. Nondestructive inspection procedures were developed to detect cracks in the skin and supporting structural elements and document the initial structural condition of the aircraft. Inspection results and flight test vibration data revealed that the FLIR created higher than expected flight loading and was the possible source of the skin cracking. The Coast Guard performed significant structural repair and enhancement on this aircraft, and additional in-flight vibration measurements were collected on the strengthened area both with and without the FLIR installed. After three months of further operational FLIR usage, the new aircraft skin with the enhanced structural modification was reinspected and found to be free of flaws. Additional US Coast Guard HC-130H aircraft are now being similarly modified to accommodate this FLIR system. Measurements of in- flight vibration levels with and without the FLIR installed, and both before and after the structural enhancement and repair were conducted on the skin and supporting structure in the aircraft's right main wheel fairing. Inspection results and techniques developed to verify the aircraft's structural integrity are discussed.

  17. Self Healing Composite for Aircraft's Structural Application

    NASA Astrophysics Data System (ADS)

    Teoh, S. H.; Chia, H. Y.; Lee, M. S.; Nasyitah, A. J. N.; Luqman, H. B. S. M.; Nurhidayah, S.; Tan, Willy. C. K.

    When one cuts himself, it is amazing to watch how quickly the body acts to mend the wound. Immediately, the body works to pull the skin around the cut back together. The concept of repair by bleeding of enclosed functional agents serves as the biomimetic inspiration of synthetic self repair systems. Such synthetic self repair systems are based on advancement in polymeric materials; the process of human thrombosis is the inspiration for the application of self healing fibres within the composite materials. Results based on flexural 3 point bend test on the prepared samples have shown that the doubled layer healed hollow fibre laminate subjected to a healing regime of 3 weeks has a healed strength increase of 27% compared to the damaged baseline laminate. These results gave us confidence that there is a great potential to adopt such self healing mechanism on actual composite parts like in aircraft's composite structures.

  18. Composite structural materials. [fiber reinforced composites for aircraft structures

    NASA Technical Reports Server (NTRS)

    Ansell, G. S.; Loewy, R. G.; Wiberly, S. E.

    1981-01-01

    Physical properties of fiber reinforced composites; structural concepts and analysis; manufacturing; reliability; and life prediction are subjects of research conducted to determine the long term integrity of composite aircraft structures under conditions pertinent to service use. Progress is reported in (1) characterizing homogeneity in composite materials; (2) developing methods for analyzing composite materials; (3) studying fatigue in composite materials; (4) determining the temperature and moisture effects on the mechanical properties of laminates; (5) numerically analyzing moisture effects; (6) numerically analyzing the micromechanics of composite fracture; (7) constructing the 727 elevator attachment rib; (8) developing the L-1011 engine drag strut (CAPCOMP 2 program); (9) analyzing mechanical joints in composites; (10) developing computer software; and (11) processing science and technology, with emphasis on the sailplane project.

  19. Robotic laser-ultrasonic inspection of composites

    NASA Astrophysics Data System (ADS)

    Néron, C.; Padioleau, C.; Blouin, A.; Monchalin, J.-P.

    2013-01-01

    In laser-ultrasonics for inspecting composites, the beams are usually directed onto the part with a computer controlled scanning mirror. This approach has sensitivity limitations when the surface is very shiny (mold facing surfaces). This limitation is eliminated by controlling the direction of the laser beams with an articulated robot, its trajectory being determined from the CAD of the part or its surface mapping from a 3D laser scanner. The scanning mirror is eliminated. We are reporting here successful implementation on a 6-axis robot.

  20. Design of piezoelectric transducers for health monitoring of composite aircraft structures

    NASA Astrophysics Data System (ADS)

    Stepinski, Tadeusz; Engholm, Marcus

    2007-04-01

    Composite structures have become a significant part of modern lightweight aircrafts. Contrary to the aluminum panels such structures are susceptible to catastrophic failure without noticeable forewarnings. One possible way of preventing catastrophic failures is integrating health monitoring systems in the critical composite structures of the aircraft. Ultrasonic resonance inspection is especially suitable for the inspection of multilayered composite structures. In our previous works we have described the principle of narrow-band ultrasonic spectroscopy (NBUS), where the surface of an inspected structure is scanned with a resonant transducer whose frequency response is monitored in a narrow frequency band. It has been proven that the NBUS method is capable of detecting both artificial disbonds and real impact defects in carbon fiber composites. In this paper we present design guidelines for optimizing narrow-band electromechanical impedance (NBE/MI) sensors that are to be integrated with a monitored composite structure. The NBE/MI sensor takes the form of a piezoelectric element bonded to the monitored structure. Parameter variations in the inspected structure result in the respective variations of the electrical impedance (admittance) of the piezoelectric sensor. Relation between the state of the inspected structure and the sensor's admittance is estimated using the network representation. Conclusions concerning the proper choice of the operating frequencies suitable for various structures are presented.

  1. Full-Scale Structural and NDI Validation Tests of Bonded Composite Doublers for Commercial Aircraft Applications

    SciTech Connect

    Roach, D.; Walkington, P.

    1999-02-01

    Composite doublers, or repair patches, provide an innovative repair technique which can enhance the way aircraft are maintained. Instead of riveting multiple steel or aluminum plates to facilitate an aircraft repair, it is possible to bond a single Boron-Epoxy composite doubler to the damaged structure. Most of the concerns surrounding composite doubler technology pertain to long-term survivability, especially in the presence of non-optimum installations, and the validation of appropriate inspection procedures. This report focuses on a series of full-scale structural and nondestructive inspection (NDI) tests that were conducted to investigate the performance of Boron-Epoxy composite doublers. Full-scale tests were conducted on fuselage panels cut from retired aircraft. These full-scale tests studied stress reductions, crack mitigation, and load transfer capabilities of composite doublers using simulated flight conditions of cabin pressure and axial stress. Also, structures which modeled key aspects of aircraft structure repairs were subjected to extreme tension, shear and bending loads to examine the composite laminate's resistance to disbond and delamination flaws. Several of the structures were loaded to failure in order to determine doubler design margins. Nondestructive inspections were conducted throughout the test series in order to validate appropriate techniques on actual aircraft structure. The test results showed that a properly designed and installed composite doubler is able to enhance fatigue life, transfer load away from damaged structure, and avoid the introduction of new stress risers (i.e. eliminate global reduction in the fatigue life of the structure). Comparisons with test data obtained prior to the doubler installation revealed that stresses in the parent material can be reduced 30%--60% through the use of the composite doubler. Tests to failure demonstrated that the bondline is able to transfer plastic strains into the doubler and that the

  2. Comparison of Requirements for Composite Structures for Aircraft and Space Applications

    NASA Technical Reports Server (NTRS)

    Raju, Ivatury S.; Elliot, Kenny B.; Hampton, Roy W.; Knight, Norman F., Jr.; Aggarwal, Pravin; Engelstad, Stephen P.; Chang, James B.

    2010-01-01

    In this report, the aircraft and space vehicle requirements for composite structures are compared. It is a valuable exercise to study composite structural design approaches used in the airframe industry and to adopt methodology that is applicable for space vehicles. The missions, environments, analysis methods, analysis validation approaches, testing programs, build quantities, inspection, and maintenance procedures used by the airframe industry, in general, are not transferable to spaceflight hardware. Therefore, while the application of composite design approaches from aircraft and other industries is appealing, many aspects cannot be directly utilized. Nevertheless, experiences and research for composite aircraft structures may be of use in unexpected arenas as space exploration technology develops, and so continued technology exchanges are encouraged.

  3. Development and validation of bonded composite doubler repairs for commercial aircraft.

    SciTech Connect

    Roach, Dennis Patrick; Rackow, Kirk A.

    2007-07-01

    substandard design and a flawed installation. In addition, the new Sol-Gel surface preparation technique was evaluated. Fatigue coupon tests produced Sol-Gel results that could be compared with a large performance database from conventional, riveted repairs. It was demonstrated that not only can composite doublers perform well in severe off-design conditions (low doubler stiffness and presence of defects in doubler installation) but that the Sol-Gel surface preparation technique is easier and quicker to carry out while still producing optimum bonding properties. Nondestructive inspection (NDI) methods were developed so that the potential for disbond and delamination growth could be monitored and crack growth mitigation could be quantified. The NDI methods were validated using full-scale test articles and the FedEx aircraft installations. It was demonstrated that specialized NDI techniques can detect flaws in composite doubler installations before they reach critical size. Probability of Detection studies were integrated into the FedEx training in order to quantify the ability of aircraft maintenance depots to properly monitor these repairs. In addition, Boeing Structural Repair and Nondestructive Testing Manuals were modified to include composite doubler repair and inspection procedures. This report presents the results from the FedEx Pilot Program that involved installation and surveillance of numerous repairs on operating aircraft. Results from critical NDI evaluations are reported in light of damage tolerance assessments for bonded composite doublers. This work has produced significant interest from airlines and aircraft manufacturers. The successful Pilot Program produced flight performance history to establish the durability of bonded composite patches as a permanent repair on commercial aircraft structures. This report discusses both the laboratory data and Pilot Program results from repair installations on operating aircraft to introduce composite doubler repairs into

  4. Critical joints in large composite aircraft structure

    NASA Technical Reports Server (NTRS)

    Nelson, W. D.; Bunin, B. L.; Hart-Smith, L. J.

    1983-01-01

    A program was conducted at Douglas Aircraft Company to develop the technology for critical structural joints of composite wing structure that meets design requirements for a 1990 commercial transport aircraft. The prime objective of the program was to demonstrate the ability to reliably predict the strength of large bolted composite joints. Ancillary testing of 180 specimens generated data on strength and load-deflection characteristics which provided input to the joint analysis. Load-sharing between fasteners in multirow bolted joints was computed by the nonlinear analysis program A4EJ. This program was used to predict strengths of 20 additional large subcomponents representing strips from a wing root chordwise splice. In most cases, the predictions were accurate to within a few percent of the test results. In some cases, the observed mode of failure was different than anticipated. The highlight of the subcomponent testing was the consistent ability to achieve gross-section failure strains close to 0.005. That represents a considerable improvement over the state of the art.

  5. Development program to certify composite doubler repair technique for commercial aircraft

    SciTech Connect

    Roach, D.P.

    1997-07-01

    Commercial airframes exceeding 20 service years often develop crack and corrosion flaws. Bonded composite doublers offer a cost effective method to safely extend aircraft lives. The Federal Aircraft Authority (FAA) has completed a project to introduce composite doubler repair technology to the commercial aircraft industry. Instead of riveting steel or aluminum plates for repair, a single composite doubler may be bonded to the damaged structure. Adhesive bonding eliminates stress concentrations caused by fastener holes. Composites are readily formed into complex shapes for repairing irregular components. Also, composite doublers can be tailored to meet specific anisotropy needs, eliminating structural stiffening in directions other than those required. Other advantages include corrosion resistance, a high strength-to-weight ratio, and potential time savings in installation. One phase of this study developed general methodologies and test programs to ensure proper performance of the technique. A second phase focused on reinforcement of an L-1011 door frame, and encompassed all lifetime tasks such as design, analysis, installation, and nondestructive inspection. This paper overviews the project and details the activities conducted to gain FAA approval for composite doubler use. Structural tests evaluated the damage tolerance and fatigue performance of composite doublers while finite element models were generated to study doubler design issues. Nondestructive inspection procedures were developed and validated using full-scale test articles. Installation dry-runs demonstrated the viability of applying composite doublers in hangar environments. The project`s documentation package was used to support installation of a Boron-Epoxy composite repair on a Delta Air Lines L-1011 aircraft. A second product of the results is a Lockheed Service Bulletin which allows the door corner composite doubler to be installed on all L-1011 aircraft. 9 refs., 10 figs., 2 tabs.

  6. Federal Aviation Administration aging aircraft nondestructive inspection research plan

    NASA Technical Reports Server (NTRS)

    Seher, Chris C.

    1992-01-01

    This paper highlights the accomplishments and plans of the Federal Aviation Administration (FAA) for the development of improved nondestructive evaluation (NDE) equipment, procedures, and training. The role of NDE in aircraft safety and the need for improvement are discussed. The FAA program participants, and coordination of activities within the program and with relevant organizations outside the program are also described.

  7. Further Evolution of Composite Doubler Aircraft Repairs Through a Focus on Niche Applications

    SciTech Connect

    ROACH,DENNIS P.

    2000-07-15

    The number of commercial airframes exceeding twenty years of service continues to grow. A typical aircraft can experience over 2,000 fatigue cycles (cabin pressurizations) and even greater flight hours in a single year. An unavoidable by-product of aircraft use is that crack and corrosion flaws develop throughout the aircraft's skin and substructure elements. Economic barriers to the purchase of new aircraft have created an aging aircraft fleet and placed even greater demands on efficient and safe repair methods. The use of bonded composite doublers offers the airframe manufacturers and aircraft maintenance facilities a cost effective method to safety extend the lives of their aircraft. Instead of riveting multiple steel or aluminum plates to facilitate an aircraft repair, it is now possible to bond a single Boron-Epoxy composite doubler to the damaged structure. The FAA's Airworthiness Assurance Center at Sandia National Labs (AANC) is conducting a program with Boeing and Federal Express to validate and introduce composite doubler repair technology to the US commercial aircraft industry. This project focuses on repair of DC-10 structure and builds on the foundation of the successful L-1011 door corner repair that was completed by the AANC, Lockheed-Martin, and Delta Air Lines. The L-1011 composite doubler repair was installed in 1997 and has not developed any flaws in over three years of service, As a follow-on effort, this DC-1O repair program investigated design, analysis, performance (durability, flaw containment, reliability), installation, and nondestructive inspection issues. Current activities are demonstrating regular use of composite doubler repairs on commercial aircraft. The primary goal of this program is to move the technology into niche applications and to streamline the design-to-installation process. Using the data accumulated to date, the team has designed, analyzed, and developed inspection techniques for an array of composite doubler repairs

  8. Impact damage in aircraft composite sandwich panels

    NASA Astrophysics Data System (ADS)

    Mordasky, Matthew D.

    An experimental study was conducted to develop an improved understanding of the damage caused by runway debris and environmental threats on aircraft structures. The velocities of impacts for stationary aircraft and aircraft under landing and takeoff speeds was investigated. The impact damage by concrete, asphalt, aluminum, hail and rubber sphere projectiles was explored in detail. Additionally, a kinetic energy and momentum experimental study was performed to look at the nature of the impacts in more detail. A method for recording the contact force history of the impact by an instrumented projectile was developed and tested. The sandwich composite investigated was an IM7-8552 unidirectional prepreg adhered to a NOMEXRTM core with an FM300K film adhesive. Impact experiments were conducted with a gas gun built in-house specifically for delivering projectiles to a sandwich composite target in this specic velocity regime (10--140 m/s). The effect on the impact damage by the projectile was investigated by ultrasonic C-scan, high speed camera and scanning electron and optical microscopy. Ultrasonic C-scans revealed the full extent of damage caused by each projectile, while the high speed camera enabled precise projectile velocity measurements that were used for striking velocity, kinetic energy and momentum analyses. Scanning electron and optical images revealed specific features of the panel failure and manufacturing artifacts within the lamina and honeycomb core. The damage of the panels by different projectiles was found to have a similar damage area for equivalent energy levels, except for rubber which had a damage area that increased greatly with striking velocity. Further investigation was taken by kinetic energy and momentum based comparisons of 19 mm diameter stainless steel sphere projectiles in order to examine the dominating damage mechanisms. The sandwich targets were struck by acrylic, aluminum, alumina, stainless steel and tungsten carbide spheres of the

  9. 14 CFR 129.105 - Aging airplane inspections and records reviews for U.S.-registered multiengine aircraft.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 3 2012-01-01 2012-01-01 false Aging airplane inspections and records... § 129.105 Aging airplane inspections and records reviews for U.S.-registered multiengine aircraft. (a... completed the aging airplane inspection and records review required by this section. During the...

  10. 14 CFR 129.105 - Aging airplane inspections and records reviews for U.S.-registered multiengine aircraft.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 3 2013-01-01 2013-01-01 false Aging airplane inspections and records... § 129.105 Aging airplane inspections and records reviews for U.S.-registered multiengine aircraft. (a... completed the aging airplane inspection and records review required by this section. During the...

  11. 14 CFR 129.105 - Aging airplane inspections and records reviews for U.S.-registered multiengine aircraft.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 3 2011-01-01 2011-01-01 false Aging airplane inspections and records... § 129.105 Aging airplane inspections and records reviews for U.S.-registered multiengine aircraft. (a... completed the aging airplane inspection and records review required by this section. During the...

  12. 14 CFR 129.105 - Aging airplane inspections and records reviews for U.S.-registered multiengine aircraft.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Aging airplane inspections and records... § 129.105 Aging airplane inspections and records reviews for U.S.-registered multiengine aircraft. (a... completed the aging airplane inspection and records review required by this section. During the...

  13. 14 CFR 129.105 - Aging airplane inspections and records reviews for U.S.-registered multiengine aircraft.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 3 2014-01-01 2014-01-01 false Aging airplane inspections and records... § 129.105 Aging airplane inspections and records reviews for U.S.-registered multiengine aircraft. (a... completed the aging airplane inspection and records review required by this section. During the...

  14. Eddy-Current Inspection Of Graphite-Fiber Composites

    NASA Technical Reports Server (NTRS)

    Workman, G. L.; Bryson, C. C.

    1993-01-01

    NASA technical memorandum describes initial research on, and proposed development of, automated system for nondestructive eddy-current inspection of parts made of graphite-fiber/epoxy-matrix composite materials. Sensors in system E-shaped or U-shaped eddy-current probes like those described in "Eddy-Current Probes For Inspecting Graphite-Fiber Composites" (MFS-26129).

  15. Flight-service program for advanced composite rudders on transport aircraft

    NASA Technical Reports Server (NTRS)

    1979-01-01

    Flight service experience and in-service inspection results are reported for DC-10 graphite composite rudders during the third year of airline service. Test results and status are also reported for ground-based and airborne graphite-epoxy specimens with three different epoxy resin systems to obtain moisture absorption data. Twenty graphite composite rudders were produced, nine of which were installed on commercial aircraft during the past three years. The rudders collectively accumulated 75,863 flight hours. The high time rudder accumulated 12,740 flight hours in slightly over 36 months. The graphite composite rudders were inspected visually at approximately 1000 flight hour intervals and ultrasonically at approximately 3000 flight hour intervals in accordance with in-service inspection plans. All rudders were judged acceptable for continued service as a result of these inspections. Composite moisture absorption data on small specimens, both ground-based and carried aboard three flight-service aircraft, are given. The specimens include Thornel 300 fibers in Narmco 5208 and 5209 resin systems, and Type AS fibers in the Hercules 3501-6 resin system.

  16. Advanced organic composite materials for aircraft structures: Future program

    NASA Technical Reports Server (NTRS)

    1987-01-01

    Revolutionary advances in structural materials have been responsible for revolutionary changes in all fields of engineering. These advances have had and are still having a significant impact on aircraft design and performance. Composites are engineered materials. Their properties are tailored through the use of a mix or blend of different constituents to maximize selected properties of strength and/or stiffness at reduced weights. More than 20 years have passed since the potentials of filamentary composite materials were identified. During the 1970s much lower cost carbon filaments became a reality and gradually designers turned from boron to carbon composites. Despite progress in this field, filamentary composites still have significant unfulfilled potential for increasing aircraft productivity; the rendering of advanced organic composite materials into production aircraft structures was disappointingly slow. Why this is and research and technology development actions that will assist in accelerating the application of advanced organic composites to production aircraft is discussed.

  17. Techno-economic requirements for composite aircraft components

    NASA Technical Reports Server (NTRS)

    Palmer, Ray

    1993-01-01

    The primary reason for use of composites is to save structural weight. A well designed composite aircraft structure will usually save 25-30 percent of a well designed metal structure. The weight savings then translates into improved performance of the aircraft in measures of greater payload, increased flying range or improved efficiency - less use of fuel. Composite materials offer technical advantages. Key technical advantages that composites offer are high stiffness, tailored strength capability, fatigue resistance, and corrosion resistance. Low thermal expansion properties produce dimensionally stable structures over a wide range of temperature. Specialty resin 'char' forming characteristics in a fire environment offer potential fire barrier application and safer aircraft. The materials and processes of composite fabrication offer the potential for lower cost structures in the near future. The application of composite materials to aircraft are discussed.

  18. Comparison of Requirements for Composite Structures for Aircraft and Space Applications

    NASA Technical Reports Server (NTRS)

    Raju, Ivatury S.; Elliott, Kenny B.; Hampton, Roy W.; Knight, Norman F., Jr.; Aggarwal, Pravin; Engelstad, Stephen P.; Chang, James B.

    2010-01-01

    In this paper, the aircraft and space vehicle requirements for composite structures are compared. It is a valuable exercise to study composite structural design approaches used in the airframe industry, and to adopt methodology that is applicable for space vehicles. The missions, environments, analysis methods, analysis validation approaches, testing programs, build quantities, inspection, and maintenance procedures used by the airframe industry, in general, are not transferable to spaceflight hardware. Therefore, while the application of composite design approaches from other industries is appealing, many aspects cannot be directly utilized. Nevertheless, experiences and research for composite aircraft structures may be of use in unexpected arenas as space exploration technology develops, and so continued technology exchanges are encouraged.

  19. Civil aircraft. [composite materials for airframes and engines

    NASA Technical Reports Server (NTRS)

    Mayer, N. J.

    1974-01-01

    This study deals with aircraft material and structural requirements, advantages of composites, airframe and engine applications, design procedures, problem areas, and future trends in civil aircraft. The selection of materials and design of structure for any given component or part must be made not only on the basis of the mechanical and structural functions, but must also consider the operational and cost parameters for civil aircraft. Composites have caused the orientation to shift from a metal-based philosophy for design, where only incremental improvements could be anticipated, to one where substantial changes in design approaches are possible. Future designs are likely to include a combination of new approaches and composite materials.

  20. Effects of commercial aircraft operating environment on composite materials

    NASA Technical Reports Server (NTRS)

    Chapman, A. J.; Hoffman, D. J.; Hodges, W. T.

    1980-01-01

    Long term effects of commercial aircraft operating environment on the properties and durability of composite materials are being systematically explored. Composite specimens configured for various mechanical property tests are exposed to environmental conditions on aircraft in scheduled airline service, on racks at major airports, and to controlled environmental conditions in the laboratory. Results of tests following these exposures will identify critical parameters affecting composite durability, and correlation of the data will aid in developing methods for predicting durability. Interim results of these studies show that mass change of composite specimens on commercial aircraft depends upon the regional climate and season, and that mass loss from composite surfaces due to ultraviolet radiation can be largely prevented by aircraft paint.

  1. Resin transfer molding for advanced composite primary aircraft structures

    NASA Technical Reports Server (NTRS)

    Markus, Alan; Palmer, Ray

    1991-01-01

    Resin Transfer Molding (RTM) has been identified by Douglas Aircraft Company (DAC) and industry to be one of the promising processes being developed today which can break the cost barrier of implementing composite primary structures into a commercial aircraft production environment. The RTM process developments and scale-up plans Douglas Aircrart will be conducting under the NASA ACT contract are discussed.

  2. Tiltrotor Research Aircraft composite blade repairs - Lessons learned

    NASA Technical Reports Server (NTRS)

    Espinosa, Paul S.; Groepler, David R.

    1992-01-01

    The XV-15, N703NA Tiltrotor Research Aircraft located at the NASA Ames Research Center, Moffett Field, California, currently uses a set of composite rotor blades of complex shape known as the advanced technology blades (ATBs). The main structural element of the blades is a D-spar constructed of unidirectional, angled fiberglass/graphite, with the aft fairing portion of the blades constructed of a fiberglass cross-ply skin bonded to a Nomex honeycomb core. The blade tip is a removable laminate shell that fits over the outboard section of the spar structure, which contains a cavity to retain balance weights. Two types of tip shells are used for research. One is highly twisted (more than a conventional helicopter blade) and has a hollow core constructed of a thin Nomex-honeycomb-and-fiberglass-skin sandwich; the other is untwisted with a solid Nomex honeycomb core and a fiberglass cross-ply skin. During initial flight testing of the blades, a number of problems in the composite structure were encountered. These problems included debonding between the fiberglass skin and the honeycomb core, failure of the honeycomb core, failures in fiberglass splices, cracks in fiberglass blocks, misalignment of mated composite parts, and failures of retention of metal fasteners. Substantial time was spent in identifying and repairing these problems. Discussed here are the types of problems encountered, the inspection procedures used to identify each problem, the repairs performed on the damaged or flawed areas, the level of criticality of the problems, and the monitoring of repaired areas. It is hoped that this discussion will help designers, analysts, and experimenters in the future as the use of composites becomes more prevalent.

  3. Tiltrotor research aircraft composite blade repairs: Lessons learned

    NASA Technical Reports Server (NTRS)

    Espinosa, Paul S.; Groepler, David R.

    1991-01-01

    The XV-15, N703NA Tiltrotor Research Aircraft located at the NASA Ames Research Center, Moffett Field, California, currently uses a set of composite rotor blades of complex shape known as the advanced technology blades (ATBs). The main structural element of the blades is a D-spar constructed of unidirectional, angled fiberglass/graphite, with the aft fairing portion of the blades constructed of a fiberglass cross-ply skin bonded to a Nomex honeycomb core. The blade tip is a removable laminate shell that fits over the outboard section of the spar structure, which contains a cavity to retain balance weights. Two types of tip shells are used for research. One is highly twisted (more than a conventional helicopter blade) and has a hollow core constructed of a thin Nomex-honeycomb-and-fiberglass-skin sandwich; the other is untwisted with a solid Nomex honeycomb core and a fiberglass cross-ply skin. During initial flight testing of the blades, a number of problems in the composite structure were encountered. These problems included debonding between the fiberglass skin and the honeycomb core, failure of the honeycomb core, failures in fiberglass splices, cracks in fiberglass blocks, misalignment of mated composite parts, and failures of retention of metal fasteners. Substantial time was spent in identifying and repairing these problems. Discussed here are the types of problems encountered, the inspection procedures used to identify each problem, the repairs performed on the damaged or flawed areas, the level of criticality of the problems, and the monitoring of repaired areas. It is hoped that this discussion will help designers, analysts, and experimenters in the future as the use of composites becomes more prevalent.

  4. Aeroelastic stability of forward swept composite winged aircraft

    NASA Technical Reports Server (NTRS)

    Weisshaar, T. A.

    1983-01-01

    This paper reviews the author's past and present aeroelastic stability and performance studies related to forward swept, composite wing aircraft. The influence of laminate elastic bend/twist coupling upon wing divergence, lateral control, and lift effectiveness will be illustrated by means of closed-form solutions, numerical analysis and simple wind-tunnel experiments. In addition, results of analyses of a freely flying flexible FSW aircraft are discussed to indicate the possible effects of the flexible forward swept wing on aircraft dynamic stability. These studies show, both theoretically and experimentally, that, if the aircraft is not carefully designed, a phenomenon referred to as body freedom flutter may appear.

  5. Evaluation of scanners for C-scan imaging in nondestructive inspection of aircraft

    SciTech Connect

    Gieske, J.H.

    1994-04-01

    The goal of this project was to produce a document that contains information on the usability and performance of commercially available, fieldable, and portable scanner systems as they apply to aircraft NDI inspections. In particular, the scanners are used to generate images of eddy current, ultrasonic, or bond tester inspection data. The scanner designs include manual scanners, semiautomated scanners, and fully automated scanners. A brief description of the functionality of each scanner type, a sketch, and a fist of the companies that support the particular design are provided. Vendors of each scanner type provided hands-on demonstrations of their equipment on real aircraft samples in the FAA Aging Aircraft Nondestructive Inspection Validation Center (AANC) in Albuquerque, NM. From evaluations recorded during the demonstrations, a matrix of scanner features and factors and ranking of the capabilities and limitations of the design, portability, articulation, performance, usability, and computer hardware/software was constructed to provide a quick reference for comparing the different scanner types. Illustrations of C-scan images obtained during the demonstration are shown.

  6. Ultrasonic inspection and compressive strength of composites with surface wrinkles

    SciTech Connect

    Fahr, A.; Forsyth, D.; Bullock, M.; Poon, C.

    1995-10-01

    Surface wrinkles in composites can adversely affect mechanical performance as well as inspection results. During conventional ultrasonic C-scan inspections, the bulging of the wrinkle scatters the sound beam and makes it difficult to detect voids beneath the wrinkles. This paper describes fabrication procedures adopted to introduce simulated surface wrinkles with pre-determined geometries as well as an ultrasonic inspection method to detect voids under wrinkles. The inspection technique is based on launching the ultrasonic beam at oblique angles enabling separation of scattering echoes from those of internal flaws. Preliminary results of compression tests on wrinkled specimens with or without simulated voids as compared to virgin specimens are also presented.

  7. 9 CFR 98.32 - Inspection of certain aircraft and other means of conveyance and shipping containers thereon...

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 9 Animals and Animal Products 1 2011-01-01 2011-01-01 false Inspection of certain aircraft and... requirements. 98.32 Section 98.32 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE EXPORTATION AND IMPORTATION OF ANIMALS (INCLUDING POULTRY) AND ANIMAL...

  8. 9 CFR 98.32 - Inspection of certain aircraft and other means of conveyance and shipping containers thereon...

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Inspection of certain aircraft and... requirements. 98.32 Section 98.32 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE EXPORTATION AND IMPORTATION OF ANIMALS (INCLUDING POULTRY) AND ANIMAL...

  9. Aircraft composites assessment by means of transient thermal NDT

    NASA Astrophysics Data System (ADS)

    Avdelidis, N. P.; Almond, D. P.; Dobbinson, A.; Hawtin, B. C.; Ibarra-Castanedo, C.; Maldague, X.

    2004-04-01

    The prerequisite for more competent and cost-effective aircraft has led to the evolution of innovative testing and evaluation procedures. Smart methods for assessing the integrity of an aircraft structure are essential to both reduce manufacturing costs and out-of-service time of aircraft due to maintenance. Nowadays, thermal non-destructive testing (NDT) is commonly used for assessing aircraft composites. In this work, certain applications of transient thermal NDT relating to the assessment of aircraft composites are presented. In particular, the following features were studied: (a) Notches under multi-ply composite patching (bonded with FM73 adhesive film to the surface of Al 2024-T3) and a simulated delamination between two plies on a multi-ply composite repair. (b) Drilling induced defects on multi-ply laminates of HEXCEL AS4/8552 carbon fibre composites. (c) Impact damage on carbon fibre reinforced plastic (CFRP) panels and honeycomb sandwich structures (bonded with AF-163-2U.03 adhesive film). (d) Through skin sensing assessment of CFRP. Real-time monitoring of all features was obtained using pulsed thermography. However, in the composite repairs cases thermal modelling and pulsed-phase thermography were also used with the intention of providing supplementary results, whilst in the case of through skin imaging thermal modelling was also used in order to demonstrate the importance of thermal contact resistance between two surfaces (skin and strut). The thermal NDT approaches used in this work gave satisfactory results in all instances.

  10. Impact of composites on future transport aircraft

    NASA Technical Reports Server (NTRS)

    Kinder, Robert H.

    1993-01-01

    In the current environment, new technology must be cost-effective in addition to improving operability. Various approaches have been used to determine the 'hurdle' or 'breakthrough' return that must be achieved to gain customer commitment for a new product or aircraft, or in this case, a new application of the technology. These approaches include return-on-investment, payback period, and addition to net worth. An easily understood figure-of-merit and one used by our airline customers is improvement in direct operating cost per seat-mile. Any new technology must buy its way onto the aircraft through reduction in direct operating cost (DOC).

  11. Low-Cost Composite Materials and Structures for Aircraft Applications

    NASA Technical Reports Server (NTRS)

    Deo, Ravi B.; Starnes, James H., Jr.; Holzwarth, Richard C.

    2003-01-01

    A survey of current applications of composite materials and structures in military, transport and General Aviation aircraft is presented to assess the maturity of composites technology, and the payoffs realized. The results of the survey show that performance requirements and the potential to reduce life cycle costs for military aircraft and direct operating costs for transport aircraft are the main reasons for the selection of composite materials for current aircraft applications. Initial acquisition costs of composite airframe components are affected by high material costs and complex certification tests which appear to discourage the widespread use of composite materials for aircraft applications. Material suppliers have performed very well to date in developing resin matrix and fiber systems for improved mechanical, durability and damage tolerance performance. The next challenge for material suppliers is to reduce material costs and to develop materials that are suitable for simplified and inexpensive manufacturing processes. The focus of airframe manufacturers should be on the development of structural designs that reduce assembly costs by the use of large-scale integration of airframe components with unitized structures and manufacturing processes that minimize excessive manual labor.

  12. Design considerations for composite fuselage structure of commercial transport aircraft

    NASA Technical Reports Server (NTRS)

    Davis, G. W.; Sakata, I. F.

    1981-01-01

    The structural, manufacturing, and service and environmental considerations that could impact the design of composite fuselage structure for commercial transport aircraft application were explored. The severity of these considerations was assessed and the principal design drivers delineated. Technical issues and potential problem areas which must be resolved before sufficient confidence is established to commit to composite materials were defined. The key issues considered are: definition of composite fuselage design specifications, damage tolerance, and crashworthiness.

  13. Nondestructive Evaluation (NDE) for Inspection of Composite Sandwich Structures

    NASA Technical Reports Server (NTRS)

    Zalameda, Joseph N.; Parker, F. Raymond

    2014-01-01

    Composite honeycomb structures are widely used in aerospace applications due to their low weight and high strength advantages. Developing nondestructive evaluation (NDE) inspection methods are essential for their safe performance. Flash thermography is a commonly used technique for composite honeycomb structure inspections due to its large area and rapid inspection capability. Flash thermography is shown to be sensitive for detection of face sheet impact damage and face sheet to core disbond. Data processing techniques, using principal component analysis to improve the defect contrast, are discussed. Limitations to the thermal detection of the core are investigated. In addition to flash thermography, X-ray computed tomography is used. The aluminum honeycomb core provides excellent X-ray contrast compared to the composite face sheet. The X-ray CT technique was used to detect impact damage, core crushing, and skin to core disbonds. Additionally, the X-ray CT technique is used to validate the thermography results.

  14. Inspecting Composites with Airborne Ultrasound: Through Thick and Thin

    NASA Astrophysics Data System (ADS)

    Hsu, David K.; Barnard, Daniel J.

    2006-03-01

    The inspection of composite materials and structures with air-coupled ultrasound has the obvious advantage that it is non-contact, non-contaminating, and free from couplants. However, the transmission efficiency from air to solid is extremely low due to the enormous difference in acoustic impedance. The development of more efficient airborne ultrasonic transducers over the years has made it possible, and even practical, to inspect composites with airborne ultrasound. It is now possible to drive newer, more efficient transducers with a portable ultrasonic flaw detector to inspect 2-inch thick solid CFRP in air. In this paper we describe our experience in applying air-coupled ultrasound to the inspection of a variety of composite structures, from honeycomb with thin composite facesheet to very thick solid laminates. General considerations for making airborne ultrasonic measurement in composite are given, and mechanism of transmission through honeycomb core, and resonance effects in transmitting through thick laminates will be described. NDE results of defects and damage in various composite structures will be presented.

  15. Flight service evaluation of Kevlar-49 epoxy composite panels in wide-bodied commercial transport aircraft

    NASA Technical Reports Server (NTRS)

    Stone, R. H.

    1982-01-01

    Kevlar-49 fairing panels, installed as flight service components on three l-1011's, were inspected after 8 years service. The fairings had accumulated a total of 62,000 hours, with one ship set having 20,850 hours service. Kevlar-49 components were found to be performing satisfactorily in service with no major problems. The only defects noted were minor impact damage, a few minor disbonds and a minor degree of fastener hole fraying and elongation. The service history to date indicates that Kevlar-49 epoxy composite materials have satisfactory service characteristics for use in aircraft secondary structures.

  16. Inspection of Impact Damage in Honeycomb Composite by Espi, Thermography and Ultrasonic Testing

    NASA Astrophysics Data System (ADS)

    Choi, Manyong; Park, Jeonghak; Kim, Wontae; Kang, Kisoo

    Honeycomb composites are now fairly widely used in civilian and military aircraft structures. Common defects found in these materials are delaminations by impact damage and their presence will lead to structural weaknesses which could lead failure of the airframe structures. It is important to develop effective non-destructive testing procedures to identify these defects and increase the safety of aircraft travel. This paper describes the detection technique of impact damage defect using thermography and ESPI. The results obtained with the two techniques are compared with ultrasonic C-scan testing. The investigation shows that both imaging NDT methods are able to identify the presence of artificial defect and impact damage. The adoption of the thermography allowed significant advantages in inspection condition, and gives smaller error in quantitative estimation of defects.

  17. Investigating accidents involving aircraft manufactured from polymer composite materials

    NASA Astrophysics Data System (ADS)

    Dunn, Leigh

    This study looks into the examination of polymer composite wreckage from the perspective of the aircraft accident investigator. It develops an understanding of the process of wreckage examination as well as identifying the potential for visual and macroscopic interpretation of polymer composite aircraft wreckage. The in-field examination of aircraft wreckage, and subsequent interpretations of material failures, can be a significant part of an aircraft accident investigation. As the use of composite materials in aircraft construction increases, the understanding of how macroscopic failure characteristics of composite materials may aid the field investigator is becoming of increasing importance.. The first phase of this research project was to explore how investigation practitioners conduct wreckage examinations. Four accident investigation case studies were examined. The analysis of the case studies provided a framework of the wreckage examination process. Subsequently, a literature survey was conducted to establish the current level of knowledge on the visual and macroscopic interpretation of polymer composite failures. Relevant literature was identified and a compendium of visual and macroscopic characteristics was created. Two full-scale polymer composite wing structures were loaded statically, in an upward bending direction, until each wing structure fractured and separated. The wing structures were subsequently examined for the existence of failure characteristics. The examination revealed that whilst characteristics were present, the fragmentation of the structure destroyed valuable evidence. A hypothetical accident scenario utilising the fractured wing structures was developed, which UK government accident investigators subsequently investigated. This provided refinement to the investigative framework and suggested further guidance on the interpretation of polymer composite failures by accident investigators..

  18. Guidelines for composite materials research related to general aviation aircraft

    NASA Technical Reports Server (NTRS)

    Dow, N. F.; Humphreys, E. A.; Rosen, B. W.

    1983-01-01

    Guidelines for research on composite materials directed toward the improvement of all aspects of their applicability for general aviation aircraft were developed from extensive studies of their performance, manufacturability, and cost effectiveness. Specific areas for research and for manufacturing development were identified and evaluated. Inputs developed from visits to manufacturers were used in part to guide these evaluations, particularly in the area of cost effectiveness. Throughout the emphasis was to direct the research toward the requirements of general aviation aircraft, for which relatively low load intensities are encountered, economy of production is a prime requirement, and yet performance still commands a premium. A number of implications regarding further directions for developments in composites to meet these requirements also emerged from the studies. Chief among these is the need for an integrated (computer program) aerodynamic/structures approach to aircraft design.

  19. Benefits and limitations of composites in carrier-based aircraft

    NASA Technical Reports Server (NTRS)

    Mcerlean, Donald P.

    1992-01-01

    There are many unique aspects of Navy air missions that lead to the differentiation between the design and performance of ship and shore-based aircraft. The major aspects are discussed from which essentially all Navy aircraft design requirements derive. (1) Navy aircraft operate from carriers at sea imposes a broad spectrum of physical conditions, constraints, and requirements ranging from the harsh sea environment, the space limitations of a carrier, takeoff and landing requirements as well as for endurance at long distances from the carrier. (2) Because the carrier and its airwing are intended to be capable of responding to a broad range of contingencies, mission flexibility is essential (maximum weapon carriage, rapid reconfiguration, multiple mission capability). (3) The embarked aircraft provides the long range defense of the battle group against air, surface and subsurface launched antiship missiles. (4) The carrier and its aircraft must operate independently and outside of normal supply lines. Taking into account these aspects, the use of composite materials in the design and performance of naval aircraft is outlined, also listing advantages and disadvantages.

  20. Pulsed terahertz inspection of non-conducting sandwich composites

    NASA Astrophysics Data System (ADS)

    Lopato, P.; Chady, T.

    2013-01-01

    Pulsed terahertz inspection enables accurate, contactless and safe for operating personnel evaluation of non-conducting structures. In this paper we present results of pulsed terahertz testing of various sandwich composite structures incorporating glass and basalt fibers based skin materials and spherecore and balsa wood based core materials. Various Time-Frequency Distributions (TFD) are utilized in order to obtain most valuable defects response.

  1. Design, ancillary testing, analysis and fabrication data for the advanced composite stabilizer for Boeing 737 aircraft, volume 2

    NASA Technical Reports Server (NTRS)

    Aniversario, R. B.; Harvey, S. T.; Mccarty, J. E.; Parsons, J. T.; Peterson, D. C.; Pritchett, L. D.; Wilson, D. R.; Wogulis, E. R.

    1982-01-01

    Results of tests conducted to demonstrate that composite structures save weight, possess long term durability, and can be fabricated at costs competitive with conventional metal structures are presented with focus on the use of graphite-epoxy in the design of a stabilizer for the Boeing 737 aircraft. Component definition, materials evaluation, material design properties, and structural elements tests are discussed. Fabrication development, as well as structural repair and inspection are also examined.

  2. Development of Textile Reinforced Composites for Aircraft Structures

    NASA Technical Reports Server (NTRS)

    Dexter, H. Benson

    1998-01-01

    NASA has been a leader in development of composite materials for aircraft applications during the past 25 years. In the early 1980's NASA and others conducted research to improve damage tolerance of composite structures through the use of toughened resins but these resins were not cost-effective. The aircraft industry wanted affordable, robust structures that could withstand the rigors of flight service with minimal damage. The cost and damage tolerance barriers of conventional laminated composites led NASA to focus on new concepts in composites which would incorporate the automated manufacturing methods of the textiles industry and which would incorporate through-the-thickness reinforcements. The NASA Advanced Composites Technology (ACT) Program provided the resources to extensively investigate the application of textile processes to next generation aircraft wing and fuselage structures. This paper discusses advanced textile material forms that have been developed, innovative machine concepts and key technology advancements required for future application of textile reinforced composites in commercial transport aircraft. Multiaxial warp knitting, triaxial braiding and through-the-thickness stitching are the three textile processes that have surfaced as the most promising for further development. Textile reinforced composite structural elements that have been developed in the NASA ACT Program are discussed. Included are braided fuselage frames and window-belt reinforcements, woven/stitched lower fuselage side panels, stitched multiaxial warp knit wing skins, and braided wing stiffeners. In addition, low-cost processing concepts such as resin transfer molding (RTM), resin film infusion (RFI), and vacuum-assisted resin transfer molding (VARTM) are discussed. Process modeling concepts to predict resin flow and cure in textile preforms are also discussed.

  3. Advanced composite stabilizer for Boeing 737 aircraft

    NASA Technical Reports Server (NTRS)

    1978-01-01

    Activities related to development of an advanced composites stabilizer for the Boeing 737 commercial transport are reported. Activities include discussion of criteria and objectives, design loads, the fatigue spectrum definition to be used for all spectrum fatigue testing, fatigue analysis, manufacturing producibility studies, the ancillary test program, quality assurance, and manufacturing development.

  4. Advanced composite elevator for Boeing 727 aircraft

    NASA Technical Reports Server (NTRS)

    1978-01-01

    Detail design activities are reported for a program to develop an advanced composites elevator for the Boeing 727 commercial transport. Design activities include discussion and results of the ancillary test programs, sustaining efforts, weight status, manufacturing producibility studies, quality assurance development, and production status.

  5. Development of composite wing carrythrough bulkheads for fighter aircraft

    NASA Technical Reports Server (NTRS)

    Goering, J. C.; Behrens, R. S.; Libeskind, Mark

    1990-01-01

    Potential weight savings due to the use of composite materials for highly loaded primary structures are being demonstrated through the design, fabrication, and test of an all composite wing carrythrough bulkhead for the F/A-18 fighter aircraft. A one piece composite design which results in a 24 percent weight savings, relative to the existing aluminum bulkhead, was developed. Critical details of this design were evaluated through element tests, and a full scale prototype component was fabricated. The structural integrity of this design will be demonstrated in a comprehensive full scale test program.

  6. Advanced composite elevator for Boeing 727 aircraft

    NASA Technical Reports Server (NTRS)

    1979-01-01

    Detail design activities are reported for a program to develop an advanced composites elevator for the Boeing 727 commercial transport. Design activities include discussion of the full scale ground test and flight test activities, the ancillary test programs, sustaining efforts, weight status, and the production status. Prior to flight testing of the advanced composites elevator, ground, flight flutter, and stability and control test plans were reviewed and approved by the FAA. Both the ground test and the flight test were conducted according to the approved plan, and were witnessed by the FAA. Three and one half shipsets have now been fabricated without any significant difficulty being encountered. Two elevator system shipsets were weighed, and results validated the 26% predicted weight reduction. The program is on schedule.

  7. Development of thermoplastic composite aircraft structures

    NASA Technical Reports Server (NTRS)

    Renieri, Michael P.; Burpo, Steven J.; Roundy, Lance M.; Todd, Stephanie A.; Kim, H. J.

    1992-01-01

    Efforts focused on the use of thermoplastic composite materials in the development of structural details associated with an advanced fighter fuselage section with applicability to transport design. In support of these designs, mechanics developments were conducted in two areas. First, a dissipative strain energy approach to material characterization and failure prediction, developed at the Naval Research Laboratory, was evaluated as a design/analysis tool. Second, a finite element formulation for thick composites was developed and incorporated into a lug analysis method which incorporates pin bending effects. Manufacturing concepts were developed for an upper fuel cell cover. A detailed trade study produced two promising concepts: fiber placement and single-step diaphragm forming. Based on the innovative design/manufacturing concepts for the fuselage section primary structure, elements were designed, fabricated, and structurally tested. These elements focused on key issues such as thick composite lugs and low cost forming of fastenerless, stiffener/moldine concepts. Manufacturing techniques included autoclave consolidation, single diaphragm consolidation (SDCC) and roll-forming.

  8. A composite system approach to aircraft cabin fire safety

    NASA Technical Reports Server (NTRS)

    Kourtides, D. A.; Parker, J. A.; Gilwee, W. J., Jr.; Lerner, N. R.; Hilado, C. J.; Labossiere, L. A.; Hsu, M. T. S.

    1976-01-01

    The thermochemical and flammability characteristics of two polymeric composites currently in use and seven others being considered for use as aircraft interior panels are described. The properties studied included: (1) limiting oxygen index of the composite constituents; (2) fire containment capability of the composite; (3) smoke evolution from the composite; (4) thermogravimetric analysis; (5) composition of the volatile products of thermal degradation; and (6) relative toxicity of the volatile products of pyrolysis. The performance of high temperature laminating resins such as bismaleimides is compared with the performance of phenolics and epoxies. The relationship of increased fire safety with the use of polymers with high anaerobic char yield is shown. Processing parameters of one of the baremaleimide composites are detailed.

  9. Welding low thermal expansion alloys for aircraft composite tooling

    SciTech Connect

    Otte, W.H.; O`Donnell, D.B.; Kiser, S.D.; Cox, C.W.

    1996-07-01

    To save weight in commercial aircraft and help military jets evade radar detection, aircraft designers specify the use of composite materials. These new designs have resulted in the use of low-expansion materials for aircraft composite tooling because they keep their dimensions during curing. However, the Fe-Ni low-expansion alloys have long presented problems during welding. When matching composition filler metals were used to match the coefficient of thermal expansion (CTE), cracking problems occurred. Filler metal compositional changes to eliminate cracking disturbed the CTE match of the weld with the base metal. A recently developed welding consumable appears to eliminate those problems. With the development of this new filler metal, high-quality crack-free welds can now be obtained with high deposition rates. Since there is a more closely-matched CTE, weldments and tools should provide longer service because of minimal effects from thermal fatigue. There have been reports of vacuum leaks in tools using the Mn-Ti filler metal, which could be directly attributable to the mismatching CTE. Using Nilo filler metal CF36 eliminates weld hot-cracking problems and provides good thermal fatigue resistance due to its excellent CTE match with the base metal, Nilo alloy 36.

  10. Evaluating the use of prior information under different pacing conditions on aircraft inspection performance: The use of virtual reality technology

    NASA Astrophysics Data System (ADS)

    Bowling, Shannon Raye

    The aircraft maintenance industry is a complex system consisting of human and machine components, because of this; much emphasis has been placed on improving aircraft-inspection performance. One proven technique for improving inspection performance is the use of training. There are several strategies that have been implemented for training, one of which is feedforward information. The use of prior information (feedforward) is known to positively affect inspection performance. This information can consist of knowledge about defect characteristics (types, severity/criticality, and location) and the probability of occurrence. Although several studies have been conducted that demonstrate the usefulness of feedforward as a training strategy, there are certain research issues that need to be addressed. This study evaluates the effect of feedforward information in a simulated 3-dimensional environment by the use of virtual reality. A controlled study was conducted to evaluate the effectiveness of feedforward information in a simulated aircraft inspection environment. The study was conducted in two phases. The first phase evaluated the difference between general and detailed inspection at different pacing levels. The second phase evaluated the effect of feedforward information pertaining to severity, probability and location. Analyses of the results showed that subjects performing detailed inspection performed significantly better than while performing general inspection. Pacing also had the effect of reducing performance for both general and detailed inspection. The study also found that as the level of feedforward information increases, performance also increases. In addition to evaluating performance measures, the study also evaluated process and subjective measures. It was found that process measures such as number of fixation points, fixation groups, mean fixation duration, and percent area covered were all affected by the treatment levels. Analyses of the subjective

  11. Inspection of bonded composites using selectively excited ultrasonic modes

    NASA Astrophysics Data System (ADS)

    Krauss, Gordon Gustav

    Improved methods of nondestructive testing (NDT) of multi-layered composites are vital for fundamental research in composites fabrication and performance. Fast, accurate NDT methods can also be used to predict catastrophic in-use failure and to reduce costly rejects during the manufacture of composite parts. Commercial normal incidence inspection techniques have generally yielded reliable detection of large areas of delamination and damage. They fail, however, to detect defects within thin bonded regions, such as disbonds, debonds, kissing bonds, and porosity. We have developed and studied a nondestructive testing technique designed to be sensitive to flaws in the bond area of adhesively bonded anisotropic materials. The technique utilizes specific ultrasonic modes which are selected through a priori modeling of the composite as a single anisotropic elastic layer. The displacement and stress profiles of the modes within the fluid loaded layer are evaluated. A propagating mode that is predicted to be highly sensitive to the bond area is then utilized in the inspection. The inspection is carried out with an apparatus designed and constructed to excite and detect the selected ultrasonic mode. The apparatus uses transducers oriented at the theoretically optimal incident angle to excite the desired mode, using a tone burst between 0.5 and 10.0 MHz. We monitor with a second transducer changes in the amplitude of the leaky component of the mode propagating in the plate. By using this apparatus we have experimentally distinguished changes in the bond areas of adhesively bonded aluminum plates and carbon-epoxy composite plates of unidirectional and quasi-isotropic lay-up, The radiated leaky wave amplitudes from poorly bonded plates were less than 50% of those from corresponding well bonded plates. We observed no significant changes in the amplitudes of normal incidence pulse-echo signals for these specimens. These results demonstrate that selective mode excitation can

  12. Indentation-Damage Visualization in CFRP by Resistive Heating: Analytical Verification of The Inspection of Aircraft Using Its Lightning Protection Systems

    NASA Astrophysics Data System (ADS)

    Suzuki, Yoshiro; Todoroki, Akira; Matsuzaki, Ryosuke; Mizutani, Yoshihiro

    Quick and automatic inspection of carbon fiber reinforced polymer (CFRP) aircraft after each flight would reduce the safety factor and allow for more flights. Visualization of impact damage was developed in an earlier study as an automatic self-monitoring method. The damaged area was visualized by selective and intense resistive heating based on its decreased through-thickness resistivity compared to undamaged areas. In the present study, the lightning protection system of a composite aircraft was used to apply a uniform electrical current distribution and electric heat to a large structure. Subsequent coupled thermal-electrical analyses showed that even small indentations (depth <0.15 mm) could be relatively easily detected in structures about 1 m in size.

  13. Technology of civil usage of composites. [in commercial aircraft structures

    NASA Technical Reports Server (NTRS)

    Kemp, D. E.

    1977-01-01

    The paper deals with the use of advanced composites in structural components of commercial aircraft. The need for testing the response of a material system to service environment is discussed along with methods for evaluating design and manufacturing aspects of a built-up structure under environmental conditions and fail-safe (damage-tolerance) evaluation of structures. Crashworthiness aspects, the fire-hazard potential, and electrical damage of composite structures are considered. Practical operational experience with commercial aircraft is reviewed for boron/epoxy foreflaps, Kevlar/epoxy fillets and fairings, graphite/epoxy spoilers, graphite/polysulfone spoilers, graphite/epoxy floor posts, boron/aluminum aft pylon skin panels, graphite/epoxy engine nose cowl outer barrels, and graphite/epoxy upper aft rudder segments.

  14. Application of finite element models to eddy current probe design for aircraft inspection

    NASA Astrophysics Data System (ADS)

    Sharma, Sarit

    Eddy current nondestructive testing (NDT) methods are used extensively in the inspection of aircraft structures. Improvements and innovations in probe design are constantly required for detection of flaws in complex multilayer aircraft structures. This thesis investigates alternate designs of eddy current probes for addressing some of these problems. An important aspect of probe design is the capability to simulate probe performance. Numerical computation and visualization of the electromagnetic fields can provide valuable insight into the design of new probes. Finite element methods have been used in this dissertation to numerically compute the electromagnetic fields associated with the probe coils, and the eddy current probe signals. A major contribution of this thesis is development of techniques to reduce the computer resource requirement in the finite element modeling: of the eddy current phenomenon. The first flaw detection problem is addressed by focusing the flux of the probe using active compensation techniques. A novel eddy current probe using a combination of coils is proposed and studied using: the 3D model simulation. The probe consists of two current carrying concentric coils to detect flaws closer to the sample edges. Detection of defects in second and third layer of samples has been demonstrated using: the remote field eddy current (RFEC) method. In the RFEC method the pickup coils are located in the far field region which leads to a large volume to be modeled numerically with large number of elements. A method involving partitioning the volume in the 3D finite element model is demonstrated for the RFEC detection of defects. Magneto-optic/eddy current imaging (MOI) techniques have shown considerable promise in the detection of corrosion in the second layer. MOI is a nondestructive testing method currently in use in aircraft frame inspection and it involves optically sensing the magnetic field induced by the eddy currents in the test sample. A

  15. Modelling the impact of aircraft emissions on atmospheric composition

    NASA Astrophysics Data System (ADS)

    Wasiuk, D. K.; Shallcross, D. E.; Lowenberg, M. H.

    2012-04-01

    Emissions of the trace gases CO2, CO, H2O, HC, NOx, and SOx that have the potential to perturb large scale atmospheric composition are accumulating in the atmosphere at an unprecedented rate as the demand for air traffic continues to grow. We investigate the global, regional and local effects of aircraft emissions on the atmosphere and climate using mathematical modelling, sensitivity simulations, and perturbation simulations. The approach is to gather results for the three main industrialised regions in the Northern Hemisphere, focusing on the 40°N - 60°N latitude belt where the majority of aircraft movements take place. A comprehensive aircraft movement database spanning years 2005 - 2012, covering 225 countries and over 223 million departures on approx. 41000 unique routes serves as a basis for our investigation. We combine air traffic data with output from an aircraft performance model including 80 distinct aircraft types, representing 216 of all the aircraft flown in the world in 2005 - 2012. This accounts for fuel burn and emissions for 99.5% of the total number of departures during that time. Simulations are being performed using a state of the art 3D Lagrangian global chemical transport model (CTM) CRI-STOCHEM for simulation of tropospheric chemistry. The model will be applied with two chemistry schemes, namely the Common Representative Intermediates (CRI) reduced chemistry scheme (220 chemical species, 609 reactions) and the near explicit Master Chemical Mechanism (MCM) chemistry scheme (5900 chemical species, 13500 reactions). This will allow us to study in detail the chemical cycles driven by NOx, governing the rate of formation of O3 which controls the production of OH and indirectly determines the lifetime of other greenhouse gases.

  16. One-sided ultrasonic inspection to detect flaws in CFRP composite solid laminates

    NASA Astrophysics Data System (ADS)

    Im, Kwang-Hee; Zhang, Guilina; Hsu, David K.; Barnard, Dan; Kim, Sun-Kyu; Yang, Yong-Jun; Hwang, Woo-Chae; Yang, In-Young; Park, Je-Woong

    2012-04-01

    The importance of Carbon Fiber reinforced plastics (CFRP) has been generally recognized, and the CFRP composite laminates are widely used. When ultrasonic inspection is applied on actual aircraft components, the part geometry often lacks flat and parallel faces and the benefit of a backwall echo maybe unavailable. So, it is very necessary to detect flaws and defects in the CFRP composite solid laminates due to the flaws of CFRP composite laminates affecting the properties of the laminate. Firstly, we used miniature potted angle beam transducers (designed for generating mode-converted shear waves or Rayleigh waves in steel) on solid laminates of composites. A pair of such transducers was mounted in a holder in a nose-to-nose fashion to be used as a scanning probe on composites. Secondly, a method was utilized to determine the porosity content of a composite lay-up by processing micrograph images of the laminate. The results from the image processing method are compared with existing data. C-scan images of CFRP samples, which were based on the impacted samples were then produced by combining the pitch-catch probe with a portable manual scanner known as the Generic Scanner ("GenScan"). The signal amplitude of pitch-catch C-scan images was also correlated to the volume percent of porosity in carbon composite laminates. Finally, a simulation was performed with the numerical Wave-2000 Code for predicting the ultrasonic wave in the sample.

  17. Open Circuit Resonant (SansEC) Sensor for Composite Damage Detection and Diagnosis in Aircraft Lightning Environments

    NASA Technical Reports Server (NTRS)

    Wang, Chuantong; Dudley, Kenneth L.; Szatkowski, George N.

    2012-01-01

    Composite materials are increasingly used in modern aircraft for reducing weight, improving fuel efficiency, and enhancing the overall design, performance, and manufacturability of airborne vehicles. Materials such as fiberglass reinforced composites (FRC) and carbon-fiber-reinforced polymers (CFRP) are being used to great advantage in airframes, wings, engine nacelles, turbine blades, fairings, fuselage and empennage structures, control surfaces and coverings. However, the potential damage from the direct and indirect effects of lightning strikes is of increased concern to aircraft designers and operators. When a lightning strike occurs, the points of attachment and detachment on the aircraft surface must be found by visual inspection, and then assessed for damage by maintenance personnel to ensure continued safe flight operations. In this paper, a new method and system for aircraft in-situ damage detection and diagnosis are presented. The method and system are based on open circuit (SansEC) sensor technology developed at NASA Langley Research Center. SansEC (Sans Electric Connection) sensor technology is a new technical framework for designing, powering, and interrogating sensors to detect damage in composite materials. Damage in composite material is generally associated with a localized change in material permittivity and/or conductivity. These changes are sensed using SansEC. Unique electrical signatures are used for damage detection and diagnosis. NASA LaRC has both experimentally and theoretically demonstrated that SansEC sensors can be effectively used for in-situ composite damage detection.

  18. Inspection of composite structures using line scanning thermography

    NASA Astrophysics Data System (ADS)

    Ley, Obdulia; Butera, Manny; Godinez, Valery

    2012-06-01

    This work deals with the non destructive analysis of different composite parts and structures using Line Scanning Thermography (LST), a non-contact inspection method based in dynamic thermography. The LST technique provides a quick and efficient methodology to scan wide areas rapidly; the technique has been used on the inspection of composite propellers, sandwich panels, motor case tubes and wind turbine blades, among others. In LST a line heat source is used to thermally excite the surface under study while an infrared detector records the transient surface temperature variation of the heated region. Line Scanning Thermography (LST), has successfully been applied to determine the thickness of metallic plates and to assess boiler tube thinning. In this paper the LST protocols developed for the detection of sub-surface defects in different composite materials commonly used in aerospace applications, plates will be presented. In most cases the thermal images acquired using LST will be compared with ultrasonic c-scans. The fundamentals of LST will be discussed, as well as the limitations of this technique for NDT inspection.

  19. Flight service evaluation of Kevlar-49 epoxy composite panels in wide-bodied commercial transport aircraft

    NASA Technical Reports Server (NTRS)

    Stone, R. H.

    1984-01-01

    Kevlar-49 fairing panels, installed as flight service components on three L-1011s, were inspected after 10 years of service. There are six Kevlar-49 panels on each aircraft: a left-hand and right-hand set of a wing-body sandwich fairing; a solid laminate under-wing fillet panel; and a 422 K (300 F) service aft engine fairing. The three L-1011s include one each in service with Eastern, Air Canada, and TWA. The fairings have accumulated a total of 79,568 hours, with one ship set having nearly 28,000 hours service. The inspections were conducted at the airlines' major maintenance bases with the participation of Lockheed Engineering. The Kevlar-49 components were found to be performing satisfactorily in service with no major problems, or any condition requiring corrective action. The only defects noted were minor impact damage, a few minor disbonds and a minor degree of fastener hole fraying and elongation. These are for the most part comparable to damage noted on fiberglass fairings. The service history obtained in this program indicates that Kevlar-49 epoxy composite materials have satisfactory service characteristics for use in aircraft secondary structure.

  20. Key issues in application of composites to transport aircraft

    NASA Technical Reports Server (NTRS)

    Stone, M.

    1978-01-01

    The application of composite materials to transport aircraft was identified and reviewed including the major contributing disciplines of design, manufacturing, and processing. Factors considered include: crashworthiness considerations (structural integrity, postcrash fires, and structural fusing), electrical/avionics subsystems integration, lightning, and P-static protection design; manufacturing development, evaluation, selection, and refining of tooling and curing procedures; and major joint design considerations. Development of the DC-10 rudder, DC-10 vertical stabilizer, and the DC-9 wing study project was reviewed. The Federal Aviation Administration interface and the effect on component design of compliance with Federal Aviation Regulation 25 Composite Guidelines are discussed.

  1. Continuous Ultrasonic Inspection of Extruded Wood-Plastic Composites

    SciTech Connect

    Tucker, Brian J. ); Bender, Donald A.

    2003-06-19

    Nondestructive evaluation (NDE) techniques are needed for in-line monitoring of wood-plastic composite (WPC) quality during manufacturing for process control. Through-transmission ultrasonic inspection is useful in characterizing stiffness and detecting cracks and voids in a range of materials; however, little is documented about ultrasound propagation in WPC materials. The objectives of this research were to determine applicable ultrasonic transducer frequencies, coupling methods, configurations and placements for wave speed monitoring and web defect detection within an extrusion process; to quantify the effects of temperature on ultrasonic parameters; and to develop a prototype ultrasonic inspection system for a full-size extrusion line. An angled beam, water-coupled ultrasonic inspection system using a pair of 50-kHz narrowband transducers was adequate for monitoring wave speed parallel to the extrusion direction. For locating internal web defects, water-coupled, 500-kHz broadband ultrasonic transducers were used in a through-thickness transmission setup. Temperature compensation factors were developed to adjust ultrasonic wave speed measurements. The prototype inspection system was demonstrated in a 55 mm conical twin-screw extrusion line.

  2. Ultrasonic inspection of adhesive joints of composite pipelines

    NASA Astrophysics Data System (ADS)

    de Almeidaa, Priscila Duarte; Alcoforado Rebello, João Marcos; Pereira, Gabriela Ribeiro; Soares, Sérgio Damasceno; Fernandez, Roman

    2014-02-01

    Composite pipelines are an attractive solution when traditional materials are not suitable for this purpose, which happens frequently at aggressive environments and also where the structural weight is a limiting factor. This work studies the application of the ultrasonic technique at the detection of defects as lack of adhesive and lack of adhesion, commonly found in adhesive joints of glass fiber reinforced plastic (GFRP) pipelines applied at onshore and offshore facilities. Computational simulations were conducted in CIVA 11software (beta version) in order to obtain the best possible configuration for the inspections, applying the pulse-echo technique. Experimental results were compared to these simulations and several transducers were tested. An inspection methodology and reference blocks were developed for the calibration of the inspections. Some samples were selected for cutting in order to compare the ultrasonic results and the real condition of the joints. Results show that smaller frequencies are suitable for the inspection of this material and focused probes present more accurate results.

  3. Modelling the impact of aircraft emissions on atmospheric composition

    NASA Astrophysics Data System (ADS)

    Wasiuk, D. K.; Lowenberg, M. H.; Shallcross, D. E.

    2012-12-01

    Emissions of the trace gases CO2, CO, H2O, HC, NOx, and SOx that have the potential to perturb large scale atmospheric composition are accumulating in the atmosphere at an unprecedented rate as the demand for air traffic continues to grow. We investigate the global and regional effects of aircraft emissions on the atmosphere and climate using mathematical modelling, sensitivity simulations, and perturbation simulations and present historical and spatial distribution evolution of the global and regional number of departures, fuel burn and emissions. A comprehensive aircraft movement database spanning years 2005 - 2012, covering 225 countries and over 223 million departures on approximately 41000 unique routes serves as a basis for our investigation. We combine air traffic data with output from an aircraft performance model (fuel burn and emissions) including 80 distinct aircraft types, representing 216 of all the aircraft flown in the world in 2005 - 2012. This accounts for fuel burn and emissions for 99.5% of the total number of departures during that time. Simulations are being performed using a state of the art 3D Lagrangian global chemical transport model (CTM) CRI-STOCHEM for simulation of tropospheric chemistry. The model is applied with the CRI (Common Representative Intermediates) chemistry scheme with 220 chemical species, and 609 reactions. This allows us to study in detail the chemical cycles driven by NOx, governing the rate of formation of O3 which controls the production of OH and indirectly determines the lifetime of other greenhouse gases. We also investigate the impact of the Eyjafjallajökull eruption on the European air traffic and present a model response to the perturbation of NOx emissions that followed.

  4. Advanced laser shearography inspection of turbo-fan engine composite fan cases

    NASA Astrophysics Data System (ADS)

    Lape, Dale; Newman, John W.; Craig, David

    1995-07-01

    Shearography inspection techniques have been developed and implemented for the inspection of aluminum honeycomb turbofan aircraft engine fan cases for the JT15D-5D. Shearography has yielded improved sensitivity to unbonds and throughput over ultrasonic techniques formerly used in the production inspection. This paper discusses vacuum stress shearography, test method verification on the JT15D-5D fan case and shearography data correlation with destructive evaluation of test parts.

  5. Composite Structure Modeling and Analysis of Advanced Aircraft Fuselage Concepts

    NASA Technical Reports Server (NTRS)

    Mukhopadhyay, Vivek; Sorokach, Michael R.

    2015-01-01

    NASA Environmentally Responsible Aviation (ERA) project and the Boeing Company are collabrating to advance the unitized damage arresting composite airframe technology with application to the Hybrid-Wing-Body (HWB) aircraft. The testing of a HWB fuselage section with Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) construction is presently being conducted at NASA Langley. Based on lessons learned from previous HWB structural design studies, improved finite-element models (FEM) of the HWB multi-bay and bulkhead assembly are developed to evaluate the performance of the PRSEUS construction. In order to assess the comparative weight reduction benefits of the PRSEUS technology, conventional cylindrical skin-stringer-frame models of a cylindrical and a double-bubble section fuselage concepts are developed. Stress analysis with design cabin-pressure load and scenario based case studies are conducted for design improvement in each case. Alternate analysis with stitched composite hat-stringers and C-frames are also presented, in addition to the foam-core sandwich frame and pultruded rod-stringer construction. The FEM structural stress, strain and weights are computed and compared for relative weight/strength benefit assessment. The structural analysis and specific weight comparison of these stitched composite advanced aircraft fuselage concepts demonstrated that the pressurized HWB fuselage section assembly can be structurally as efficient as the conventional cylindrical fuselage section with composite stringer-frame and PRSEUS construction, and significantly better than the conventional aluminum construction and the double-bubble section concept.

  6. Automated exterior inspection of an aircraft with a pan-tilt-zoom camera mounted on a mobile robot

    NASA Astrophysics Data System (ADS)

    Jovančević, Igor; Larnier, Stanislas; Orteu, Jean-José; Sentenac, Thierry

    2015-11-01

    This paper deals with an automated preflight aircraft inspection using a pan-tilt-zoom camera mounted on a mobile robot moving autonomously around the aircraft. The general topic is image processing framework for detection and exterior inspection of different types of items, such as closed or unlatched door, mechanical defect on the engine, the integrity of the empennage, or damage caused by impacts or cracks. The detection step allows to focus on the regions of interest and point the camera toward the item to be checked. It is based on the detection of regular shapes, such as rounded corner rectangles, circles, and ellipses. The inspection task relies on clues, such as uniformity of isolated image regions, convexity of segmented shapes, and periodicity of the image intensity signal. The approach is applied to the inspection of four items of Airbus A320: oxygen bay handle, air-inlet vent, static ports, and fan blades. The results are promising and demonstrate the feasibility of an automated exterior inspection.

  7. Inspection and evaluation of dry fibers in thick composites

    NASA Astrophysics Data System (ADS)

    Dayal, Vinay; Chakrapani, Sunil Kishore; Barnard, Daniel

    2013-01-01

    This paper presents the investigation of dry fibers in thick composites. Dry fibers can be defined as lack of epoxy in localized regions. These local regions act as potential defects in thick composites under compressive loads and act as an initiation point for defects such as matrix cracking and delamination. Detection and characterization of dryness in glass/epoxy composites, with thickness greater than one inch, is presented in this paper. One inch samples with dry fibers were fabricated and tested. Detection is carried out with the help of air coupled ultrasonics in both through transmission and singled sided inspection. To characterize the amount of epoxy, time of flight data was correlated with density and fiber volume fraction. Based on the observations a technique was developed for characterization of dryness.

  8. Advanced composite vertical fin for L-1011 aircraft

    NASA Technical Reports Server (NTRS)

    Jackson, A. C.

    1984-01-01

    The structural box of the L-1011 vertical fin was redesigned using advanced composite materials. The box was fabricated and ground tested to verify the structural integrity. This report summarizes the complete program starting with the design and analysis and proceeds through the process development ancillary test program production readiness verification testing, fabrication of the full-scale fin boxes and the full-scale ground testing. The program showed that advanced composites can economically and effectively be used in the design and fabrication of medium primary structures for commercial aircraft. Static-strength variability was demonstrated to be comparable to metal structures and the long term durability of advanced composite components was demonstrated.

  9. Energy-absorbing-beam design for composite aircraft subfloors

    NASA Technical Reports Server (NTRS)

    Carden, Huey D.; Kellas, Sotiris

    1993-01-01

    Data have been presented from the design support testing of composite energy absorbing (EA) aircraft subfloor structures. The focus of the current study is the design and testing of subfloor structural concepts that would limit the loads transmitted to occupants to less than 20 g at crush speeds of approximately 30 fps. The EA composite subfloor is being designed to replace an existing noncrashworthy metallic subfloor in a composite aircraft prior to a full-scale crash test. A sandwich spar construction of a sine wave beam was chosen for evaluation and was found to have excellent energy absorbing characteristics. The design objective of obtaining sustained crushing loads of the spar between 200-300 lbf/inch were achieved for potentially limiting occupants loads to around 20 g's. Stroke efficiency of up to 79 percent of the initial spar height under desired sustained crushing loads was obtained which is far greater than the level provided by metal structure. Additionally, a substantial residual spar stiffness was retained after impact, and the flange integrity, which is critical for seat retention, was maintained after crushing of the spars.

  10. Environmental exposure effects on composite materials for commercial aircraft

    NASA Technical Reports Server (NTRS)

    Hoffman, Daniel J.; Bielawski, William J.

    1991-01-01

    A study was conducted to determine the effects of long term flight and ground exposure on three commercially available graphite-epoxy material systems: T300/5208, T300/5209, and T300/934. Sets of specimens were exposed on commercial aircraft and ground racks for 1, 2, 3, 5, and 10 years. Inflight specimen sites included both the interior and exterior of aircraft based in Hawaii, Texas, and New Zealand. Ground racks were located at NASA-Dryden and the above mentioned states. Similar specimens were exposed to controlled lab conditions for up to 2 years. After each exposure, specimens were tested for residual strength and a dryout procedure was used to measure moisture content. Both room and high temperature residual strengths were measured and expressed as a pct. of the unexposed strength. Lab exposures included the effects of time alone, moisture, time on moist specimens, weatherometer, and simulated ground-air-ground cycling. Residual strengths of the long term specimens were compared with residual strengths of the lab specimens. Strength retention depended on the exposure condition and the material system. Results showed that composite materials can be successfully used on commercial aircraft if environmental effects are considered.

  11. Lightning protection technology for small general aviation composite material aircraft

    NASA Technical Reports Server (NTRS)

    Plumer, J. A.; Setzer, T. E.; Siddiqi, S.

    1993-01-01

    An on going NASA (Small Business Innovative Research) SBIR Phase II design and development program will produce the first lightning protected, fiberglass, General Aviation aircraft that is available as a kit. The results obtained so far in development testing of typical components of the aircraft kit, such as the wing and fuselage panels indicate that the lightning protection design methodology and materials chosen are capable of protecting such small composite airframes from lightning puncture and structural damage associated with severe threat lightning strikes. The primary objective of the program has been to develop a lightening protection design for full scale test airframe and verify its adequacy with full scale laboratory testing, thus enabling production and sale of owner-built, lightning-protected, Stoddard-Hamilton Aircraft, Inc. Glasair II airplanes. A second objective has been to provide lightning protection design guidelines for the General Aviation industry, and to enable these airplanes to meet lightening protection requirements for certification of small airplanes. This paper describes the protection design approaches and development testing results obtained thus far in the program, together with design methodology which can achieve the design goals listed above. The presentation of this paper will also include results of some of the full scale verification tests, which will have been completed by the time of this conference.

  12. Advanced composite vertical stabilizer for DC-10 transport aircraft

    NASA Technical Reports Server (NTRS)

    Stephens, C. O.

    1979-01-01

    Structural design, tooling, fabrication, and test activities are reported for a program to develop an advanced composite vertical stabilizer (CVS) for the DC 10 Commercial Transport Aircraft. Structural design details are described and the status of structural and weight analyses are reported. A structural weight reduction of 21.7% is currently predicted. Test results are discussed for sine wave stiffened shear webs containing representative of the CVS spar webs and for lightning current transfer and tests on a panel representative of the CVS skins.

  13. Development of Stitched Composite Structure for Advanced Aircraft

    NASA Technical Reports Server (NTRS)

    Jegley, Dawn; Przekop, Adam; Rouse, Marshall; Lovejoy, Andrew; Velicki, Alex; Linton, Kim; Wu, Hsi-Yung; Baraja, Jaime; Thrash, Patrick; Hoffman, Krishna

    2015-01-01

    NASA has created the Environmentally Responsible Aviation Project to develop technologies which will reduce the impact of aviation on the environment. A critical aspect of this pursuit is the development of a lighter, more robust airframe that will enable the introduction of unconventional aircraft configurations. NASA and The Boeing Company are working together to develop a structural concept that is lightweight and an advancement beyond state-of-the-art composites. The Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) is an integrally stiffened panel design where elements are stitched together and designed to maintain residual load-carrying capabilities under a variety of damage scenarios. With the PRSEUS concept, through-the-thickness stitches are applied through dry fabric prior to resin infusion, and replace fasteners throughout each integral panel. Through-the-thickness reinforcement at discontinuities, such as along flange edges, has been shown to suppress delamination and turn cracks, which expands the design space and leads to lighter designs. The pultruded rod provides stiffening away from the more vulnerable skin surface and improves bending stiffness. A series of building blocks were evaluated to explore the fundamental assumptions related to the capability and advantages of PRSEUS panels. These building blocks addressed tension, compression, and pressure loading conditions. The emphasis of the development work has been to assess the loading capability, damage arrestment features, repairability, post-buckling behavior, and response of PRSEUS flat panels to out-of plane pressure loading. The results of this building-block program from coupons through an 80%-scale pressure box have demonstrated the viability of a PRSEUS center body for the Hybrid Wing Body (HWB) transport aircraft. This development program shows that the PRSEUS benefits are also applicable to traditional tube-andwing aircraft, those of advanced configurations, and other

  14. Smart aircraft composite structures with embedded small-diameter optical fiber sensors

    NASA Astrophysics Data System (ADS)

    Takeda, Nobuo; Minakuchi, Shu

    2012-02-01

    This talk describes the embedded optical fiber sensor systems for smart aircraft composite structures. First, a summary of the current Japanese national project on structural integrity diagnosis of aircraft composite structures is described with special emphasis on the use of embedded small-diameter optical fiber sensors including FBG sensors. Then, some examples of life-cycle monitoring of aircraft composite structures are presented using embedded small-diameter optical fiber sensors for low-cost and reliable manufacturing merits.

  15. Open Circuit Resonant (SansEC) Sensor Technology for Lightning Mitigation and Damage Detection and Diagnosis for Composite Aircraft Applications

    NASA Technical Reports Server (NTRS)

    Szatkowski, George N.; Dudley, Kenneth L.; Smith, Laura J.; Wang, Chuantong; Ticatch, Larry A.

    2014-01-01

    Traditional methods to protect composite aircraft from lightning strike damage rely on a conductive layer embedded on or within the surface of the aircraft composite skin. This method is effective at preventing major direct effect damage and minimizes indirect effects to aircraft systems from lightning strike attachment, but provides no additional benefit for the added parasitic weight from the conductive layer. When a known lightning strike occurs, the points of attachment and detachment on the aircraft surface are visually inspected and checked for damage by maintenance personnel to ensure continued safe flight operations. A new multi-functional lightning strike protection (LSP) method has been developed to provide aircraft lightning strike protection, damage detection and diagnosis for composite aircraft surfaces. The method incorporates a SansEC sensor array on the aircraft exterior surfaces forming a "Smart skin" surface for aircraft lightning zones certified to withstand strikes up to 100 kiloamperes peak current. SansEC sensors are open-circuit devices comprised of conductive trace spiral patterns sans (without) electrical connections. The SansEC sensor is an electromagnetic resonator having specific resonant parameters (frequency, amplitude, bandwidth & phase) which when electromagnetically coupled with a composite substrate will indicate the electrical impedance of the composite through a change in its resonant response. Any measureable shift in the resonant characteristics can be an indication of damage to the composite caused by a lightning strike or from other means. The SansEC sensor method is intended to diagnose damage for both in-situ health monitoring or ground inspections. In this paper, the theoretical mathematical framework is established for the use of open circuit sensors to perform damage detection and diagnosis on carbon fiber composites. Both computational and experimental analyses were conducted to validate this new method and system for

  16. Simulation of ultrasonic inspection of curved composites using a hybrid semi-analytical/numerical code

    NASA Astrophysics Data System (ADS)

    Reverdy, Frédéric; Mahaut, Steve; Dominguez, Nicolas; Dubois, Philippe

    2015-03-01

    Carbon Fiber reinforced composites are increasingly used in structural parts in the aeronautics industry, as they allow to reduce the weight of aircrafts while maintaining high mechanical performances. However, such structures can be complicated to inspect due to their complex geometries and complex composite properties, leading to highly heterogeneous and anisotropic materials. Different potential damages and manufacturing flaws related to these parts are to be detected: porosities, ply waviness, delaminations after impact. Ultrasonic inspection, which is commonly used to test the full volume of composite panels, thus has to cope with both complex wave propagation (within anisotropic parts whose crystallographic orientation varies according to the layers structure) and flaw interaction (local distortion of plies such as ply waviness, small pores, structural noise due to periodicity patterns…). Developing NDT procedures for those parts therefore requires simulation tools to help for understanding those phenomena, and to optimize probes and techniques. Within the CIVA multi-techniques platform, CEA-LIST has developed semi-analytical tools for ultrasonic techniques, which have the advantages of high computational efficiency (fast calculations), but with limited range of application due to some hypothesis (for instance, homogenization approaches which don't allow to take account of structural noise). On the other hand, numerical methods such as finite element (FEM) or finite difference in time domain (FDTD) are more suitable to compute ultrasonic wave propagation and defect scattering in complex materials such as composite but require more computational efforts. Hybrid methods couple semi-analytical solutions and numerical computations in limited spatial domains to handle complex cases with high computation performances. In CIVA we have integrated a hybrid model that combines the semi-analytical methods developed at CEA to FDTD codes developed at Airbus Group

  17. Portable Ultrasonic Guided Wave Inspection with MACRO Fiber Composite Actuators

    NASA Astrophysics Data System (ADS)

    Haig, A.; Mudge, P.; Catton, P.; Balachandran, W.

    2010-02-01

    The development of portable ultrasonic guided wave transducer arrays that utilize Macro Fiber Composite actuators (MFCs) is described. Portable inspection equipment can make use of ultrasonic guided waves to rapidly screen large areas of many types of engineering structures for defects. The defect finding performance combined with the difficulty of application determines how much the engineering industry makes use of this non-destructive, non-disruptive technology. The developments with MFCs have the potential to make considerable improvements in both these aspects. MFCs are highly efficient because they use interdigital electrodes to facilitate the extensional, d33 displacement mode. Their fiber composite design allows them to be thin, lightweight, flexible and durable. The flexibility affords them conformance with curved surfaces, which can facilitate good mechanical coupling. The suitability of a given transducer for Long Range Ultrasonic Testing is governed by the nature and amplitude of the displacement that it excites/senses in the contact area of the target structure. This nature is explored for MFCs through directional sensitivity analysis and empirical testing. Housing methods that facilitate non-permanent coupling techniques are discussed. Finally, arrangements of arrays of MFCs for the guided wave inspection of plates and pipes are considered and some broad design criteria are given.

  18. A study on the utilization of advanced composites in commercial aircraft wing structure: Executive summary

    NASA Technical Reports Server (NTRS)

    Watts, D. J.

    1978-01-01

    The overall wing study objectives are to study and plan the effort by commercial transport aircraft manufacturers to accomplish the transition from current conventional materials and practices to extensive use of advanced composites in wings of aircraft that will enter service in the 1985-1990 time period. Specific wing study objectives are to define the technology and data needed to support an aircraft manufacturer's commitment to utilize composites primary wing structure in future production aircraft and to develop plans for a composite wing technology program which will provide the needed technology and data.

  19. Finite Element Modeling of the Thermographic Inspection for Composite Materials

    NASA Technical Reports Server (NTRS)

    Bucinell, Ronald B.

    1996-01-01

    The performance of composite materials is dependent on the constituent materials selected, material structural geometry, and the fabrication process. Flaws can form in composite materials as a result of the fabrication process, handling in the manufacturing environment, and exposure in the service environment to anomalous activity. Often these flaws show no indication on the surface of the material while having the potential of substantially degrading the integrity of the composite structure. For this reason it is important to have available inspection techniques that can reliably detect sub-surface defects such as inter-ply disbonds, inter-ply cracks, porosity, and density changes caused by variations in fiber volume content. Many non-destructive evaluation techniques (NDE) are capable of detecting sub-surface flaws in composite materials. These include shearography, video image correlation, ultrasonic, acoustic emissions, and X-ray. The difficulty with most of these techniques is that they are time consuming and often difficult to apply to full scale structures. An NDE technique that appears to have the capability to quickly and easily detect flaws in composite structure is thermography. This technique uses heat to detect flaws. Heat is applied to the surface of a structure with the use of a heat lamp or heat gun. A thermographic camera is then pointed at the surface and records the surface temperature as the composite structure cools. Flaws in the material will cause the thermal-mechanical material response to change. Thus, the surface over an area where a flaw is present will cool differently than regions where flaws do not exist. This paper discusses the effort made to thermo-mechanically model the thermography process. First the material properties and physical parameters used in the model will be explained. This will be followed by a detailed discussion of the finite element model used. Finally, the result of the model will be summarized along with

  20. On Field Inspection of Composite Pipes Using Pulsed Phase Thermography

    NASA Astrophysics Data System (ADS)

    Souza, M. P. V.; Almeida, R. M.; Rebello, J. M. A.; Soares, S. D.

    2010-02-01

    The pulsed phase thermography (PPT) is becoming a valuable tool on the detection and dimensioning of defects on composite materials. However, the most of the works that adopt the PPT needs very sophisticated equipment to thermal excitation of the specimen and data acquisition. This work uses the concepts of the PPT to inspect sections of fiberglass reinforced epoxy pipes used on adhesively bonded joints applied on the oil industry on extraction and transportation of fluids, using low cost and simple equipment to thermal excitation. A MatLab routine to data processing was used intending to achieve a fast and reliable non-destructive method to be performed on field. Amplitude and phase images are generated from the infrared images without any pre-processing technique revealing simulated defects that were impossible to be detected on the original data. A study of how deep the thermal wave can reach along the thickness of this kind of material is also performed trying to estipulate the limits of the technique aiming on the detection of problems on adhesive layers using two heat sources: halogen lamp and industrial air blower. Results support the possibility of implementing a reliable and low cost method of inspection on field to various values of pipe thicknesses found on plants of the oil industry.

  1. Damage tolerance assessment of bonded composite doubler repairs for commercial aircraft applications

    SciTech Connect

    Roach, D.

    1998-08-01

    The Federal Aviation Administration has sponsored a project at its Airworthiness Assurance NDI Validation Center (AANC) to validate the use of bonded composite doublers on commercial aircraft. A specific application was chosen in order to provide a proof-of-concept driving force behind this test and analysis project. However, the data stemming from this study serves as a comprehensive evaluation of bonded composite doublers for general use. The associated documentation package provides guidance regarding the design, analysis, installation, damage tolerance, and nondestructive inspection of these doublers. This report describes a series of fatigue and strength tests which were conducted to study the damage tolerance of Boron-Epoxy composite doublers. Tension-tension fatigue and ultimate strength tests attempted to grow engineered flaws in coupons with composite doublers bonded to aluminum skin. An array of design parameters, including various flaw scenarios, the effects of surface impact, and other off-design conditions, were studied. The structural tests were used to: (1) assess the potential for interply delaminations and disbonds between the aluminum and the laminate, and (2) determine the load transfer and crack mitigation capabilities of composite doublers in the presence of severe defects. A series of specimens were subjected to ultimate tension tests in order to determine strength values and failure modes. It was demonstrated that even in the presence of extensive damage in the original structure (cracks, material loss) and in spite of non-optimum installations (adhesive disbonds), the composite doubler allowed the structure to survive more than 144,000 cycles of fatigue loading. Installation flaws in the composite laminate did not propagate over 216,000 fatigue cycles. Furthermore, the added impediments of impact--severe enough to deform the parent aluminum skin--and hot-wet exposure did not effect the doubler`s performance. Since the tests were conducting

  2. Potential release of fibers from burning carbon composites. [aircraft fires

    NASA Technical Reports Server (NTRS)

    Bell, V. L.

    1980-01-01

    A comprehensive experimental carbon fiber source program was conducted to determine the potential for the release of conductive carbon fibers from burning composites. Laboratory testing determined the relative importance of several parameters influencing the amounts of single fibers released, while large-scale aviation jet fuel pool fires provided realistic confirmation of the laboratory data. The dimensions and size distributions of fire-released carbon fibers were determined, not only for those of concern in an electrical sense, but also for those of potential interest from a health and environmental standpoint. Fire plume and chemistry studies were performed with large pool fires to provide an experimental input into an analytical modelling of simulated aircraft crash fires. A study of a high voltage spark system resulted in a promising device for the detection, counting, and sizing of electrically conductive fibers, for both active and passive modes of operation.

  3. Damage tolerant composite wing panels for transport aircraft

    NASA Technical Reports Server (NTRS)

    Smith, Peter J.; Wilson, Robert D.; Gibbins, M. N.

    1985-01-01

    Commercial aircraft advanced composite wing surface panels were tested for durability and damage tolerance. The wing of a fuel-efficient, 200-passenger airplane for 1990 delivery was sized using grahite-epoxy materials. The damage tolerance program was structured to allow a systematic progression from material evaluations to the optimized large panel verification tests. The program included coupon testing to evaluate toughened material systems, static and fatigue tests of compression coupons with varying amounts of impact damage, element tests of three-stiffener panels to evaluate upper wing panel design concepts, and the wing structure damage environment was studied. A series of technology demonstration tests of large compression panels is performed. A repair investigation is included in the final large panel test.

  4. Environmental exposure effects on composite materials for commercial aircraft

    NASA Technical Reports Server (NTRS)

    Gibbins, M. N.; Hoffman, D. J.

    1982-01-01

    The effects of environmental exposure on composite materials are studied. The environments considered are representative of those experienced by commercial jet aircraft. Initial results have been compiled for the following material systems: T300/5208, T300/5209 and T300/934. Specimens were exposed on the exterior and interior of Boeing 737 airplanes of three airlines, and to continuous ground level exposure at four locations. In addition specimens were exposed in the laboratory to conditions such as: simulated ground-air-ground, weatherometer, and moisture. Residual strength results are presented for specimens exposed for up to two years at three ground level exposure locations and on airplanes from two airlines. Test results are also given for specimens exposed to the laboratory simulated environments. Test results indicate that short beam shear strength is sensitive to environmental exposure and dependent on the level of absorbed moisture.

  5. Environmental exposure effects on composite materials for commercial aircraft

    NASA Technical Reports Server (NTRS)

    Coggeshall, R. L.

    1985-01-01

    The effects of environmental exposure on composite materials are determined. The environments considered are representative of those experienced by commercial jet aircraft. Initial results have been compiled for the following material systems: T300/5208, T300/5209, and T300/934. Future results will include AS-1/3501-6 and Kevlar 49/F161-188. Specimens are exposed on the exterior and interior of 737 airplanes of three airlines, and to continuous ground-level exposure at four locations. In addition, specimens are exposed in the laboratory to conditions such as: simulated ground-air-ground, weatherometer, and moisture. Residual strength results are presented for specimens exposed for up to five years at five ground-level exposure locations and on airplanes from one airline.

  6. Advances in the Use of Thermography to Inspect Composite Tanks for Liquid Fuel Propulsion Systems

    NASA Technical Reports Server (NTRS)

    Lansing, Matthew D.; Russell, Samuel S.; Walker, James L.; Jones, Clyde S. (Technical Monitor)

    2001-01-01

    This viewgraph presentation gives an overview of advances in the use of thermography to inspect composite tanks for liquid fuel propulsion systems. Details are given on the thermographic inspection system, thermographic analysis method (includes scan and defect map, method of inspection, and inclusions, ply wrinkle, and delamination defects), graphite composite cryogenic feedline (including method, image map, and deep/shallow inclusions and resin rich area defects), and material degradation nondestructive evaluation.

  7. Non-Contact Inspection of Composites Using Air-Coupled Ultrasound

    NASA Astrophysics Data System (ADS)

    Peters, J.; Kommareddy, V.; Liu, Z.; Fei, D.; Hsu, D.

    2003-03-01

    Conventional ultrasonic tests are conducted using water as a transmitting medium. Water coupled ultrasound cannot be applied to certain water-sensitive or porous materials and is more difficult to use in the field. In contrast, air-coupled ultrasound is non-contact and has clear advantages over water-coupled testing. The technology of air-coupled ultrasound has gained maturity in recent years. Some systems have become commercially available and researchers are pursuing several different modalities of air-coupled transduction. This paper reports our experience of applying air-coupled ultrasound to the inspection of flaws, damage, and normal internal structures of composite parts. Through-transmission C-scans at 400 kHz using a focused receiver has resolution sufficient to image honeycomb cells in the sandwich core. With the transmitter and receiver on the same side of a laminate. Lamb waves were generated and used for the imaging of substructures. Air-coupled scan results are presented for flaw detection and damage in aircraft composite structures.

  8. Comparison of X-Ray, Millimeter Wave, Shearography and Through-Transmission Ultrasonic Methods for Inspection of Honeycomb Composites

    NASA Astrophysics Data System (ADS)

    Abou-Khousa, M. A.; Ryley, A.; Kharkovsky, S.; Zoughi, R.; Daniels, D.; Kreitinger, N.; Steffes, G.

    2007-03-01

    Honeycomb composites are increasingly finding utility in a variety of environments and applications, such as aircraft structural components, flight control components, radomes, etc. In-service and environmental stresses can produce unwanted flaws that adversely affect the structural integrity and functionality of these composites. These flaws may be in the forms of disbonds, delaminations, impact damage, crushed honeycomb, moisture intrusion, internal cracks, etc. There are several nondestructive testing (NDT) methods that may be used to inspect these composites for the presence and evaluation of these flaws. Such NDT methods include X-ray computed tomography, near-field millimeter wave, shearography, and ultrasonic testing. To assess the capabilities of these methods for honeycomb composite inspection, two honeycomb composites panels were produced with several embedded flaws and missing material primarily representing planar disbonds at various levels within the thickness of the panels and with different shapes. Subsequently, the aforementioned NDT methods were used to produce images of the two panels. This paper presents the results of these investigations and a comparison among the capabilities of these methods.

  9. Recent advances in bonded composite repair technology for metallic aircraft components

    SciTech Connect

    Baker, A.A.; Chester, R.J.

    1993-12-31

    Advanced fiber composites such as boron/epoxy can be employed as adhesively bonded patches to repair or to reinforce metallic aerospace components. This approach provides many advantages over conventional mechanically fastened metallic patches, including improved fatigue behavior, reduced corrosion and easy conformance to complex aerodynamic contours. Bonded composite repairs have been shown to provide high levels of bond durability under aircraft operating conditions. The recent application of bonded composite repairs to military and civil aircraft is described.

  10. Simulation of an Impact Test of the All-Composite Lear Fan Aircraft

    NASA Technical Reports Server (NTRS)

    Stockwell, Alan E.; Jones, Lisa E. (Technical Monitor)

    2002-01-01

    An MSC.Dytran model of an all-composite Lear Fan aircraft fuselage was developed to simulate an impact test conducted at the NASA Langley Research Center Impact Dynamics Research Facility (IDRF). The test was the second of two Lear Fan impact tests. The purpose of the second test was to evaluate the performance of retrofitted composite energy-absorbing floor beams. A computerized photogrammetric survey was performed to provide airframe geometric coordinates, and over 5000 points were processed and imported into MSC.Patran via an IGES file. MSC.Patran was then used to develop the curves and surfaces and to mesh the finite element model. A model of the energy-absorbing floor beams was developed separately and then integrated into the Lear Fan model. Structural responses of components such as the wings were compared with experimental data or previously published analytical data wherever possible. Comparisons with experimental results were used to guide structural model modifications to improve the simulation performance. This process was based largely on qualitative (video and still camera images and post-test inspections) rather than quantitative results due to the relatively few accelerometers attached to the structure.

  11. Recent NASA progress in composites. [application to spacecraft and aircraft structures

    NASA Technical Reports Server (NTRS)

    Heldenfels, R. R.

    1975-01-01

    The application of composites in aerospace vehicle structures is reviewed. Research and technology program results and specific applications to space vehicles, aircraft engines, and aircraft and helicopter structures are discussed in detail. Particular emphasis is given to flight service evaluation programs that are or will be accumulating substantial experience with secondary and primary structural components on military and commercial aircraft to increase confidence in their use.

  12. Provisional rules for the inspection of aircraft adopted by the French Bureau Veritas

    NASA Technical Reports Server (NTRS)

    1924-01-01

    These new regulations are intended to replace those of November 1, 1922, and give the directions to be followed in the supervision of aircraft by the agents of the Aeronautical Section of the Bureau Veritas.

  13. Aircraft

    DOEpatents

    Hibbs, B.D.; Lissaman, P.B.S.; Morgan, W.R.; Radkey, R.L.

    1998-09-22

    This disclosure provides a solar rechargeable aircraft that is inexpensive to produce, is steerable, and can remain airborne almost indefinitely. The preferred aircraft is a span-loaded flying wing, having no fuselage or rudder. Travelling at relatively slow speeds, and having a two-hundred foot wingspan that mounts photovoltaic cells on most all of the wing`s top surface, the aircraft uses only differential thrust of its eight propellers to turn. Each of five sections of the wing has one or more engines and photovoltaic arrays, and produces its own lift independent of the other sections, to avoid loading them. Five two-sided photovoltaic arrays, in all, are mounted on the wing, and receive photovoltaic energy both incident on top of the wing, and which is incident also from below, through a bottom, transparent surface. The aircraft is capable of a top speed of about ninety miles per hour, which enables the aircraft to attain and can continuously maintain altitudes of up to sixty-five thousand feet. Regenerative fuel cells in the wing store excess electricity for use at night, such that the aircraft can sustain its elevation indefinitely. A main spar of the wing doubles as a pressure vessel that houses hydrogen and oxygen gases for use in the regenerative fuel cell. The aircraft has a wide variety of applications, which include weather monitoring and atmospheric testing, communications, surveillance, and other applications as well. 31 figs.

  14. Aircraft

    DOEpatents

    Hibbs, Bart D.; Lissaman, Peter B. S.; Morgan, Walter R.; Radkey, Robert L.

    1998-01-01

    This disclosure provides a solar rechargeable aircraft that is inexpensive to produce, is steerable, and can remain airborne almost indefinitely. The preferred aircraft is a span-loaded flying wing, having no fuselage or rudder. Travelling at relatively slow speeds, and having a two-hundred foot wingspan that mounts photovoltaic cells on most all of the wing's top surface, the aircraft uses only differential thrust of its eight propellers to turn. Each of five sections of the wing has one or more engines and photovoltaic arrays, and produces its own lift independent of the other sections, to avoid loading them. Five two-sided photovoltaic arrays, in all, are mounted on the wing, and receive photovoltaic energy both incident on top of the wing, and which is incident also from below, through a bottom, transparent surface. The aircraft is capable of a top speed of about ninety miles per hour, which enables the aircraft to attain and can continuously maintain altitudes of up to sixty-five thousand feet. Regenerative fuel cells in the wing store excess electricity for use at night, such that the aircraft can sustain its elevation indefinitely. A main spar of the wing doubles as a pressure vessel that houses hydrogen and oxygen gasses for use in the regenerative fuel cell. The aircraft has a wide variety of applications, which include weather monitoring and atmospheric testing, communications, surveillance, and other applications as well.

  15. Full-scale testing and progressive damage modeling of sandwich composite aircraft fuselage structure

    NASA Astrophysics Data System (ADS)

    Leone, Frank A., Jr.

    A comprehensive experimental and computational investigation was conducted to characterize the fracture behavior and structural response of large sandwich composite aircraft fuselage panels containing artificial damage in the form of holes and notches. Full-scale tests were conducted where panels were subjected to quasi-static combined pressure, hoop, and axial loading up to failure. The panels were constructed using plain-weave carbon/epoxy prepreg face sheets and a Nomex honeycomb core. Panel deformation and notch tip damage development were monitored during the tests using several techniques, including optical observations, strain gages, digital image correlation (DIC), acoustic emission (AE), and frequency response (FR). Additional pretest and posttest inspections were performed via thermography, computer-aided tap tests, ultrasound, x-radiography, and scanning electron microscopy. The framework to simulate damage progression and to predict residual strength through use of the finite element (FE) method was developed. The DIC provided local and full-field strain fields corresponding to changes in the state-of-damage and identified the strain components driving damage progression. AE was monitored during loading of all panels and data analysis methodologies were developed to enable real-time determination of damage initiation, progression, and severity in large composite structures. The FR technique has been developed, evaluating its potential as a real-time nondestructive inspection technique applicable to large composite structures. Due to the large disparity in scale between the fuselage panels and the artificial damage, a global/local analysis was performed. The global FE models fully represented the specific geometries, composite lay-ups, and loading mechanisms of the full-scale tests. A progressive damage model was implemented in the local FE models, allowing the gradual failure of elements in the vicinity of the artificial damage. A set of modifications

  16. Nde for Water Ingression in Composite Radomes on Aircraft

    NASA Astrophysics Data System (ADS)

    Hsu, David K.; Barnard, Daniel J.; Kite, Adam H.; Kim, Ki-Bok

    2008-02-01

    Aircraft radomes, being an electronic window for the radar, are made of nonconducting composite sandwiches with glass or silica fiber-reinforced facesheet and Nomex honeycomb or foam core. Trapped water or moisture can produce shadow on the image and severely degrade the performance of the radar. To detect water ingression in radomes, the available NDE techniques include x-ray radiography, infrared thermography, and a radome moisture meter that measures the RF power loss caused by the presence of water. In this work we explore the utility of commercially available capacitive sensors with co-planar electrodes that measure the change of the dielectric constant in the fringing field. These capacitive sensors, such as the electronic stud finder and moisture meters for wood, can exploit the large dielectric constant of water and serve as one-sided detectors for water and moisture in radomes. The sensitivities of the various moisture meters were compared in the experimental detection of water introduced into radome panels and water and moisture trapped in retired radomes.

  17. Smart patches: self-monitoring composite patches for the repair of aircraft

    NASA Astrophysics Data System (ADS)

    Crossley, Samuel D.; Marioli-Riga, Zaira; Tsamasphyros, George; Kanderakis, George; Furnarakis, Nikos; Ikiades, Aris; Konstantaki, Mary

    2004-03-01

    Conventional aircraft repair techniques employ bolted or riveted metallic reinforcements, which frequently introduce additional stress concentrations leading to further cracking and creating areas difficult or impossible to inspect. Bonded composite repairs ("patches") result in the elimination of stress concentrations caused by additional fastener holes, improved strength to weight ratio and present a sealed interface. This reduces even further the danger of corrosion and fretting under the repair, gives greater flexibility in design and lessens application time while lengthening fatigue life. Embedding optical fibres and sensors into the patch, and combining this with advanced data collection and processing systems, creating a so-called "smart patch", will enable the real-time assessment of aircraft structural integrity resulting in reliable prediction of maintenance requirements for repaired structures. This paper describes the current state of the art in smart patch technology, and includes a detailed description of the measurement problem and of the work being undertaken to solve it, at both the component and system level. An analysis of typical crack behaviour, based on FE modelling is presented and this demonstrates the need for optical strain sensors having a very short gauge length. The paper discusses the advantages and limitations of very short Fibre Bragg Gratings (FBGs) in this context and also provides early experimental data from 1mm and 2mm gratings which have been fabricated for this purpose. The paper also describes the impact of the measurement and environmental constraints on the design of the FBG interrogation system and presents the results of initial trials. The work is being undertaken in the framework of a collaborative project (ACIDS) which is co-funded by the European Commission.

  18. Costs and benefits of composite material applications to a civil STOL aircraft

    NASA Technical Reports Server (NTRS)

    Logan, T. R.

    1974-01-01

    Costs and benefits of advanced composite primary airframe structure were studied to determine cost-effective applications to a civil STOL aircraft designed for introduction in the early 1980 time period. Applications were assessed by comparing costs and weights with a baseline metal aircraft which served as a basis of comparison throughout the study. Costs as well as weights were estimated from specific designs of principal airframe components, thus establishing a cost-data base for the study. Cost effectiveness was judged by an analysis that compared direct operating costs and return on investment of the composite and baseline aircraft. A systems operations analysis was performed to judge effects of the smaller, lighter composite aircraft. It was determined that broad applications of advanced composites to the airframe considered could be cost-effective, but this advantage is strongly influenced by structural configuration and several key cost categories.

  19. Flight service evaluation of kevlar-49 epoxy composite panels in wide-bodied commercial transport aircraft: Flight service report

    NASA Technical Reports Server (NTRS)

    Stone, R. H.

    1981-01-01

    Kevlar-49 fairing panels, installed as flight service components on three L-1011s, were inspected after 7 years service. There are six Kevlar-49 panels on each aircraft: a left hand and right hand set of a wing-body sandwich fairing; a slid laminate under-wing fillet panel; and a 422 K service aft engine fairing. The three L-1011s include one each in service with Eastern, Air Canada, and TWA. The fairings have accumulated a total of 52,500 hours, with one ship set having 17.700 hours service. The inspections were conducted at the airlines' major maintenance bases with the participation of Lockheed Engineering. The Kevlar-49 components were found to be performing satisfactorily in service with no major problems or any condition requiring corrective action. The only defects noted were minor impact damage and a minor degree of fastener hole fraying and elongation. These are for the most part comparable to damage noted on fiberglass fairings. The service history to date indicates that Kevlar-49 epoxy composite materials have satisfactory service characteristics for use in aircraft secondary structure.

  20. Advanced manufacturing development of a composite empennage component for L-1011 aircraft

    NASA Technical Reports Server (NTRS)

    Alva, T.; Henkel, J.; Johnson, R.; Carll, B.; Jackson, A.; Mosesian, B.; Brozovic, R.; Obrien, R.; Eudaily, R.

    1982-01-01

    This is the final report of technical work conducted during the fourth phase of a multiphase program having the objective of the design, development and flight evaluation of an advanced composite empennage component manufactured in a production environment at a cost competitive with those of its metal counterpart, and at a weight savings of at least 20 percent. The empennage component selected for this program is the vertical fin box of the L-1011 aircraft. The box structure extends from the fuselage production joint to the tip rib and includes front and rear spars. During Phase 4 of the program, production quality tooling was designed and manufactured to produce three sets of covers, ribs, spars, miscellaneous parts, and subassemblies to assemble three complete ACVF units. Recurring and nonrecurring cost data were compiled and documented in the updated producibility/design to cost plan. Nondestruct inspections, quality control tests, and quality acceptance tests were performed in accordance with the quality assurance plan and the structural integrity control plan. Records were maintained to provide traceability of material and parts throughout the manufacturing development phase. It was also determined that additional tooling would not be required to support the current and projected L-1011 production rate.

  1. Multi-layer aircraft structure inspection using super-sensitive Remote-Field Eddy-Current system

    NASA Astrophysics Data System (ADS)

    Sun, Yushi; Ouyang, Tianhe; Udpa, Satish

    2001-04-01

    The Remote-Field Eddy-Current Technique (RFECT) has recently been applied for detecting deeply hidden cracks and corrosion in samples simulating multi-layer aluminum aircraft structures. Experimental measurement results have shown high sensitivity of the RFECT system in these applications. For example, the system can detect a 0.03″ long fatigue crack on a fastener hole located on the bottom surface of the bottom layer. The crack is located 0.446″ below the inspection surface. The second example shows that when scanning a multiple layer aluminum sample with total thickness of 0.29″, the RFECT system can detect wall thinning as small as 1% of the total thickness.

  2. Electromagnetic on-aircraft antenna radiation in the presence of composite plates

    NASA Technical Reports Server (NTRS)

    Kan, S. H-T.; Rojas, R. G.

    1994-01-01

    The UTD-based NEWAIR3 code is modified such that it can model modern aircraft by composite plates. One good model of conductor-backed composites is the impedance boundary condition where the composites are replaced by surfaces with complex impedances. This impedance-plate model is then used to model the composite plates in the NEWAIR3 code. In most applications, the aircraft distorts the desired radiation pattern of the antenna. However, test examples conducted in this report have shown that the undesired scattered fields are minimized if the right impedance values are chosen for the surface impedance plates.

  3. An Enhanced Vacuum Cure Technique for On-Aircraft Repair of Carbon-Bismaleimide Composites

    NASA Astrophysics Data System (ADS)

    Rider, Andrew N.; Baker, Alan A.; Wang, Chun H.; Smith, Graeme

    2011-06-01

    Carbon/bismaleimide (BMI) composite is increasingly employed in critical load carrying aircraft structures designed to operate at temperatures approaching 180°C. The high post-cure temperature (above 220°C) required to fully react the BMI resin, however, renders existing on-aircraft prepreg or wet layup repair methods invalid. This paper presents a new on-aircraft repair technique for carbon/BMI composites. The composite prepregs are first warm-staged to improve the ability to evacuate entrapped air. Then the patch is cured in the scarf cavity using the vacuum bag technique, followed by off-aircraft post-cure. The fully cured patch then can be bonded using a structural adhesive.

  4. 14 CFR 129.109 - Supplemental inspections for U.S.-registered aircraft.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... result of original type certification or later increase in capacity have— (1) A maximum type certificated... 14 Aeronautics and Space 3 2011-01-01 2011-01-01 false Supplemental inspections for U.S..., DEPARTMENT OF TRANSPORTATION (CONTINUED) AIR CARRIERS AND OPERATORS FOR COMPENSATION OR HIRE:...

  5. Photometric stereo sensor for robot-assisted industrial quality inspection of coated composite material surfaces

    NASA Astrophysics Data System (ADS)

    Weigl, Eva; Zambal, Sebastian; Stöger, Matthias; Eitzinger, Christian

    2015-04-01

    While composite materials are increasingly used in modern industry, the quality control in terms of vision-based surface inspection remains a challenging task. Due to the often complex and three-dimensional structures, a manual inspection of these components is nearly impossible. We present a photometric stereo sensor system including an industrial robotic arm for positioning the sensor relative to the inspected part. Two approaches are discussed: stop-and-go positioning and continuous positioning. Results are presented on typical defects that appear on various composite material surfaces in the production process.

  6. Evaluation of efficiency of aircraft liquid waste treatment and identification of daily inspection indices: a case study in Changchun, China.

    PubMed

    Xu, Jianling; Yang, Jiaqi; Zhao, Nan; Sheng, Lianxi; Zhao, Yuanhui; Tang, Zhanhui

    2013-07-01

    Evaluation of the efficiency of aircraft liquid waste treatment has previously been conducted to prevent pollution of the environment. The current study aimed to provide a set of practical methods for efficient airport sanitary supervision. Aircraft liquid waste was collected at Longjia International Airport, Changchun from multiple flights. The efficiency of liquid waste treatment as well as the water quality of the wastewater processed via a second-stage wastewater facility were examined by measuring a number of physical, chemical, and biological indices. Our results indicated that treatment solely via resolvable sanitizing liquid was not sufficient. Although the contents of first-class pollutants all met the requirements of the standard criteria, the contents of a number of second-class pollutants did not satisfy these criteria. However, after further treatment via a second-stage wastewater facility installed at the airport, all indices reached second-grade requirements of the discharge standard. We suggest that daily inspection and quarantine indices at airports should include the suspension content, biological oxygen demands after 5 days, chemical oxygen demand total organic carbon content, amino nitrogen content, total phosphorous content, and the level of fecal coliforms. PMID:23192680

  7. The FAA`s Aging Aircraft Nondestructive Inspection Validation Center at Sandia National Laboratories: An introduction

    SciTech Connect

    Walter, P.

    1995-07-01

    In these times of budget tightening for both government and private industry, this issue of Materials Evaluation is devoted to describing a cooperative relationship leveraging resources in the Department of Transportation`s Federal Aviation Administration (FAA) and the Department of Energy`s Sandia National Laboratories. This relationship resulted in a facility whose purpose is to assess technologies intended to enhance the reliability and cost effectiveness of inspection in the civil aviation industry. Eight articles are presented to describe this facility and its related activities. The center, located at the Albuquerque International Airport, has as its mission assessing and -- where justified -- encouraging the transfer of emerging inspection technologies to the civil aviation industry.

  8. Robotic inspection of fiber reinforced composites using phased array UT

    NASA Astrophysics Data System (ADS)

    Stetson, Jeffrey T.; De Odorico, Walter

    2014-02-01

    Ultrasound is the current NDE method of choice to inspect large fiber reinforced airframe structures. Over the last 15 years Cartesian based scanning machines using conventional ultrasound techniques have been employed by all airframe OEMs and their top tier suppliers to perform these inspections. Technical advances in both computing power and commercially available, multi-axis robots now facilitate a new generation of scanning machines. These machines use multiple end effector tools taking full advantage of phased array ultrasound technologies yielding substantial improvements in inspection quality and productivity. This paper outlines the general architecture for these new robotic scanning systems as well as details the variety of ultrasonic techniques available for use with them including advances such as wide area phased array scanning and sound field adaptation for non-flat, non-parallel surfaces.

  9. A study on the utilization of advanced composites in commercial aircraft wing structure

    NASA Technical Reports Server (NTRS)

    Watts, D. J.

    1978-01-01

    A study was conducted to define the technology and data needed to support the introduction of advanced composite materials in the wing structure of future production aircraft. The study accomplished the following: (1) definition of acceptance factors, (2) identification of technology issues, (3) evaluation of six candidate wing structures, (4) evaluation of five program options, (5) definition of a composite wing technology development plan, (6) identification of full-scale tests, (7) estimation of program costs for the total development plan, (8) forecast of future utilization of composites in commercial transport aircraft and (9) identification of critical technologies for timely program planning.

  10. Advanced composite elevator for Boeing 727 aircraft, volume 2

    NASA Technical Reports Server (NTRS)

    Chovil, D. V.; Grant, W. D.; Jamison, E. S.; Syder, H.; Desper, O. E.; Harvey, S. T.; Mccarty, J. E.

    1980-01-01

    Preliminary design activity consisted of developing and analyzing alternate design concepts and selecting the optimum elevator configuration. This included trade studies in which durability, inspectability, producibility, repairability, and customer acceptance were evaluated. Preliminary development efforts consisted of evaluating and selecting material, identifying ancillary structural development test requirements, and defining full scale ground and flight test requirements necessary to obtain Federal Aviation Administration (FAA) certification. After selection of the optimum elevator configuration, detail design was begun and included basic configuration design improvements resulting from manufacturing verification hardware, the ancillary test program, weight analysis, and structural analysis. Detail and assembly tools were designed and fabricated to support a full-scope production program, rather than a limited run. The producibility development programs were used to verify tooling approaches, fabrication processes, and inspection methods for the production mode. Quality parts were readily fabricated and assembled with a minimum rejection rate, using prior inspection methods.

  11. Thermography Inspection for Early Detection of Composite Damage in Structures During Fatigue Loading

    NASA Technical Reports Server (NTRS)

    Zalameda, Joseph N.; Burke, Eric R.; Parker, F. Raymond; Seebo, Jeffrey P.; Wright, Christopher W.; Bly, James B.

    2012-01-01

    Advanced composite structures are commonly tested under controlled loading. Understanding the initiation and progression of composite damage under load is critical for validating design concepts and structural analysis tools. Thermal nondestructive evaluation (NDE) is used to detect and characterize damage in composite structures during fatigue loading. A difference image processing algorithm is demonstrated to enhance damage detection and characterization by removing thermal variations not associated with defects. In addition, a one-dimensional multilayered thermal model is used to characterize damage. Lastly, the thermography results are compared to other inspections such as non-immersion ultrasonic inspections and computed tomography X-ray.

  12. Environmental Exposure Effects on Composite Materials for Commercial Aircraft

    NASA Technical Reports Server (NTRS)

    Hoffman, D. J.

    1981-01-01

    This period's activities were highlighted by continued long term and accelerated lab exposure testing, and by completion of all fabrication tasks on the optional material systems, AS1/3501-6 and Kevlar 49/F161-188. Initial baseline testing was performed on the two optional material systems. Long term exposure specimens were returned from three of the four ground rack sites and from two of the three aircraft locations. Test data from specimens returned from Dryden after 2 years exposure do not indicate continuing trends of strength reduction from the 1 year data. Test data from specimens returned from the Wellington, new Zealand ground rack and on Air New Zealand aircraft after 1 year exposure show strength changes fairly typical of other locations.

  13. Status of Advanced Stitched Unitized Composite Aircraft Structures

    NASA Technical Reports Server (NTRS)

    Jegley, Dawn C.; Velicki, Alex

    2013-01-01

    NASA has created the Environmentally Responsible Aviation (ERA) Project to explore and document the feasibility, benefits and technical risk of advanced vehicle configurations and enabling technologies that will reduce the impact of aviation on the environment. A critical aspect of this pursuit is the development of a lighter, more robust airframe that will enable the introduction of unconventional aircraft configurations that have higher lift-to-drag ratios, reduced drag, and lower community noise levels. The primary structural concept being developed under the ERA project in the Airframe Technology element is the Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) concept. This paper describes how researchers at NASA and The Boeing Company are working together to develop fundamental PRSEUS technologies that could someday be implemented on a transport size aircraft with high aspect ratio wings or unconventional shapes such as a hybrid wing body airplane design.

  14. Environmental exposure effects on composite materials for commercial aircraft

    NASA Technical Reports Server (NTRS)

    Hoffman, D. J.

    1978-01-01

    Activities reported include completion of the program design tasks, resolution of a high fiber volume problem and resumption of specimen fabrication, fixture fabrication, and progress on the analysis methodology and definition of the typical aircraft environment. Program design activities including test specimens, specimen holding fixtures, flap-track fairing tailcones, and ground exposure racks were completed. The problem experienced in obtaining acceptable fiber volume fraction results on two of the selected graphite epoxy material systems was resolved with an alteration to the bagging procedure called out in BAC 5562. The revised bagging procedure, involving lower numbers of bleeder plies, produces acceptable results. All required laminates for the contract have now been laid up and cured. Progress in the area of analysis methodology has been centered about definition of the environment that a commercial transport aircraft undergoes. The selected methodology is analagous to fatigue life assessment.

  15. Development of Ultrasonic and Fabry-Perot Interferometer for Non-Destruction Inspection of Aging Aircraft

    NASA Technical Reports Server (NTRS)

    Smith, Alphonso C.

    1998-01-01

    Fabry-Perot Interferometer (FPI) sensor detection system was continued and refined modifications were made in the data acquisition and evaluation process during the last year. The ultrasonic and FPI detection system was improved from one to multiple sensor detectors. Physical models were developed to understand the physical phenomenon of this work. Multilayered flawed samples were fabricated for inspection by a prototype ultrasonic and FPI detection. Experimental data was verified with simulated results. Undergraduate students that were associated with this research gained valuable knowledge from this experience. This was a learning process helping students to understand the importance of research and its application to solve important technological problems. As a result of our students exposure to this research two and planning to continue this type of research work in graduate school. A prototype instrument package was laboratory tested an actual airframe structure for documentation purposes.

  16. Fuel containment and damage tolerance for large composite primary aircraft structures. Phase 1: Testing

    NASA Technical Reports Server (NTRS)

    Sandifer, J. P.

    1983-01-01

    Technical problems associated with fuel containment and damage tolerance of composite material wings for transport aircraft were identified. The major tasks are the following: (1) the preliminary design of damage tolerant wing surface using composite materials; (2) the evaluation of fuel sealing and lightning protection methods for a composite material wing; and (3) an experimental investigation of the damage tolerant characteristics of toughened resin graphite/epoxy materials. The test results, the test techniques, and the test data are presented.

  17. Development of pressure containment and damage tolerance technology for composite fuselage structures in large transport aircraft

    NASA Technical Reports Server (NTRS)

    Smith, P. J.; Thomson, L. W.; Wilson, R. D.

    1986-01-01

    NASA sponsored composites research and development programs were set in place to develop the critical engineering technologies in large transport aircraft structures. This NASA-Boeing program focused on the critical issues of damage tolerance and pressure containment generic to the fuselage structure of large pressurized aircraft. Skin-stringer and honeycomb sandwich composite fuselage shell designs were evaluated to resolve these issues. Analyses were developed to model the structural response of the fuselage shell designs, and a development test program evaluated the selected design configurations to appropriate load conditions.

  18. Metal aircraft structural elements reinforced with graphite filamentary composites

    NASA Technical Reports Server (NTRS)

    Berg, K. R.; Ramsey, J.

    1972-01-01

    Strain compatibility equations are used to evaluate the thermal stresses existing when unidirectional graphite composites are bonded to aluminum structures. Based on thermal stresses and optimum placement of the composite, skin-stringer aluminum panels are optimized for minimum weight compression panels with selective composite reinforcement. Composite reinforced skin-stringer panels are thermal cycled to determine the effect of thermal fatigue on structural integrity. Both cycled and uncycled panels are tested in compression and tension. Test results are correlated with predicted loads. Use of filamentary graphite composites is an efficient method of reinforcing metal structures, but care must be taken to minimize thermal stresses.

  19. Study on utilization of advanced composites in commercial aircraft wing structures. Volume 1: Executive summary

    NASA Technical Reports Server (NTRS)

    Sakata, I. F.; Ostrom, R. B.; Cardinale, S. V.

    1978-01-01

    The effort required by commercial transport manufacturers to accomplish the transition from current construction materials and practices to extensive use of composites in aircraft wings was investigated. The engineering and manufacturing disciplines which normally participate in the design, development, and production of an aircraft were employed to ensure that all of the factors that would enter a decision to commit to production of a composite wing structure were addressed. A conceptual design of an advanced technology reduced energy aircraft provided the framework for identifying and investigating unique design aspects. A plan development effort defined the essential technology needs and formulated approaches for effecting the required wing development. The wing development program plans, resource needs, and recommendations are summarized.

  20. Eddy-Current Probes For Inspecting Graphite-Fiber Composites

    NASA Technical Reports Server (NTRS)

    Workman, Gary L.; Wang, Morgan

    1992-01-01

    Eddy-current probes with E-shaped and U-shaped magnetic cores developed to detect flaws in graphite-fiber/epoxy and other composites. Magnetic fields more concentrated, yielding better coupling with specimens.

  1. Inspection of composite materials with an advanced ultrasonic flaw detector

    NASA Astrophysics Data System (ADS)

    Yamamoto, W.

    The structures and shapes of the composite material products are described. Methods of ultrasonic wave detection are described. New damage detection equipment for laminate and honeycomb structures is addressed.

  2. Studying impact damage on carbon-fiber reinforced aircraft composite panels with sonicir

    SciTech Connect

    Han Xiaoyan; Zhang Ding; He Qi; Song Yuyang; Lubowicki, Anthony; Zhao Xinyue; Newaz, Golam.; Favro, Lawrence D.; Thomas, Robert L.

    2011-06-23

    Composites are becoming more important materials in commercial aircraft structures such as the fuselage and wings with the new B787 Dreamliner from Boeing which has the target to utilize 50% by weight of composite materials. Carbon-fiber reinforced composites are the material of choice in aircraft structures. This is due to their light weight and high strength (high strength-to-weight ratio), high specific stiffness, tailorability of properties, design flexibility etc. Especially, by reducing the aircraft's body weight by using such lighter structures, the cost of fuel can be greatly reduced with the high jet fuel price for commercial airlines. However, these composites are prone to impact damage and the damage may occur without any observable sign on the surface, yet resulting in delaminations and disbonds that may occur well within the layers. We are studying the impact problem with carbon-fiber reinforced composite panels and developing SonicIR for this application as a fast and wide-area NDE technology. In this paper, we present our results in studying composite structures including carbon-fiber reinforced composite materials, and preliminary quantitative studies on delamination type defect depth identification in the panels.

  3. Fiber Bragg grating sensing in smart composite patch repairs for aging aircraft

    NASA Astrophysics Data System (ADS)

    Kressel, I.; Botsev, Y.; Leibovich, H.; Guedj, P.; Ben-Simon, U.; Ghilai, G.; Gorbatov, Nahum; Gali, S.; Tur, Moshe

    2005-05-01

    A low spatial resolution Fiber-Bragg-Grating sensor net is proposed for real time health monitoring of bonded composite patches used for aging aircraft structural repairs. FBG reading are shown to have direct correlation with the structural integrity of the patch, making this concept attractive for airworthiness assessment of bonded repairs.

  4. Polymer, metal and ceramic matrix composites for advanced aircraft engine applications

    NASA Technical Reports Server (NTRS)

    Mcdanels, D. L.; Serafini, T. T.; Dicarlo, J. A.

    1985-01-01

    Advanced aircraft engine research within NASA Lewis is being focused on propulsion systems for subsonic, supersonic, and hypersonic aircraft. Each of these flight regimes requires different types of engines, but all require advanced materials to meet their goals of performance, thrust-to-weight ratio, and fuel efficiency. The high strength/weight and stiffness/weight properties of resin, metal, and ceramic matrix composites will play an increasingly key role in meeting these performance requirements. At NASA Lewis, research is ongoing to apply graphite/polyimide composites to engine components and to develop polymer matrices with higher operating temperature capabilities. Metal matrix composites, using magnesium, aluminum, titanium, and superalloy matrices, are being developed for application to static and rotating engine components, as well as for space applications, over a broad temperature range. Ceramic matrix composites are also being examined to increase the toughness and reliability of ceramics for application to high-temperature engine structures and components.

  5. Study on utilization of advanced composites in commercial aircraft wing structures, volume 2

    NASA Technical Reports Server (NTRS)

    Sakata, I. F.; Ostrom, R. B.

    1978-01-01

    A plan is defined for a composite wing development effort which will assist commercial transport manufacturers in reaching a level of technology readiness where the utilization of composite wing structure is a cost competitive option for a new aircraft production plan. The recommended development effort consists of two programs: a joint government/industry material development program and a wing structure development program. Both programs are described in detail.

  6. Line scanning thermography for rapid nondestructive inspection of large scale composites

    SciTech Connect

    Chung, S.; Ley, O.; Godinez, V.; Bandos, B.

    2011-06-23

    As next generation structures are utilizing larger amounts of composite materials, a rigorous and reliable method is needed to inspect these structures in order to prevent catastrophic failure and extend service life. Current inspection methods, such as ultrasonic, generally require extended down time and man hours as they are typically carried out via point-by-point measurements. A novel Line Scanning Thermography (LST) System has been developed for the non-contact, large-scale field inspection of composite structures with faster scanning times than conventional thermography systems. LST is a patented dynamic thermography technique where the heat source and thermal camera move in tandem, which allows the continuous scan of long surfaces without the loss of resolution. The current system can inspect an area of 10 in{sup 2} per 1 second, and has a resolution of 0.05x0.03 in{sup 2}. Advanced data gathering protocols have been implemented for near-real time damage visualization and post-analysis algorithms for damage interpretation. The system has been used to successfully detect defects (delamination, dry areas) in fiber-reinforced composite sandwich panels for Navy applications, as well as impact damage in composite missile cases and armor ceramic panels.

  7. Composites boost 21st-century aircraft engines

    NASA Technical Reports Server (NTRS)

    Stephens, Joseph R.

    1990-01-01

    Research and development in light-weight, high-temperature composite materials for ultrahigh-bypass engines to be used in high-speed civil transport/rotocraft is presented. It is noted that the expected benefits to be attained by this R&D include weight reduction, lowered fuel consumption, and lower direct operating costs. A major effort underway in this area is the Advanced High Temperature Engine Materials Technology Program (HITEMP) of NASA, which focuses on providing revolutionary high-temperature composite materials: to 425 C (800 F) for polymer-matrix composites (PMCs), to 1250 C (2280 F) for metal-matrix/intermetallic-matrix composites (MMCs/IMCs), and to as high as 1650 C (3000 F) for ceramic-matrix composites (CMCs). Analytical modeling is being used to investigate the structural behavior of these advanced materials in six distinct areas: micromechanics, deformation and damage, fatigue, fracture, trade-off studies, and load definition. It is concluded that the development of advanced materials such as high-temperature composites is highly dependent on the availability of high-temperature fibers. The wide range of fiber characteristics needed will require the development of more than one fiber. In general, a candidate fiber should have low density, high strength, high stiffness, a CTE matching the matrix, chemical compatibility with the matrix, environmental stability and appropriate fiber diameter.

  8. Impact Testing of Composites for Aircraft Engine Fan Cases

    NASA Technical Reports Server (NTRS)

    Roberts, Gary D.; Revilock, Duane M.; Binienda, Wieslaw K.; Nie, Walter Z.; Mackenzie, S. Ben; Todd, Kevin B.

    2001-01-01

    Before composite materials can be considered for use in the fan case of a commercial jet engine, the performance of a composite structure under blade-out loads needs to be demonstrated. The objective of this program is to develop an efficient test and analysis method for evaluating potential composite case concepts. Ballistic impact tests were performed on laminated glass/epoxy composites in order to identify potential failure modes and to provide data for analysis. Flat 7x7 in. panels were impacted with cylindrical titanium projectiles, and 15 in. diameter half-rings were impacted with wedge-shaped titanium projectiles. Composite failure involved local fiber fracture as well as tearing and delamination on a larger scale. A 36 in. diameter full-ring subcomponent was proposed for larger scale testing. Explicit, transient, finite element analyses were used to evaluate impact dynamics and subsequent global deformation for the proposed full-ring subcomponent test. Analyses on half-ring and quarter ring configurations indicated that less expensive smaller scale tests could be used to screen potential composite concepts when evaluation of local impact damage is the primary concern.

  9. Application study of filamentary composites in a commercial jet aircraft fuselage

    NASA Technical Reports Server (NTRS)

    Johnson, R. W.; June, R. R.

    1972-01-01

    A study of applications of filamentary composite materials to aircraft fuselage structure was performed. General design criteria were established and material studies conducted using the 727-200 forebody as the primary structural component. Three design approaches to the use of composites were investigated: uniaxial reinforcement of metal structure, uniaxial and biaxial reinforcement of metal structure, and an all-composite design. Materials application studies for all three concepts were conducted on fuselage shell panels, keel beam, floor beams, floor panels, body frames, fail-safe straps, and window frames. Cost benefit studies were conducted and developmental program costs estimated. On the basis of weight savings, cost effectiveness, developmental program costs, and potential for early application on commercial aircraft, the unaxial design is recommended for a 5-year flight service evaluation program.

  10. Novel matrix resins for composites for aircraft primary structures, phase 1

    NASA Technical Reports Server (NTRS)

    Woo, Edmund P.; Puckett, P. M.; Maynard, S.; Bishop, M. T.; Bruza, K. J.; Godschalx, J. P.; Mullins, M. J.

    1992-01-01

    The objective of the contract is the development of matrix resins with improved processability and properties for composites for primarily aircraft structures. To this end, several resins/systems were identified for subsonic and supersonic applications. For subsonic aircraft, a series of epoxy resins suitable for RTM and powder prepreg was shown to give composites with about 40 ksi compressive strength after impact (CAI) and 200 F/wet mechanical performance. For supersonic applications, a thermoplastic toughened cyanate prepreg system has demonstrated excellent resistance to heat aging at 360 F for 4000 hours, 40 ksi CAI and useful mechanical properties at greater than or equal to 310 F. An AB-BCB-maleimide resin was identified as a leading candidate for the HSCT. Composite panels fabricated by RTM show CAI of approximately 50 ksi, 350 F/wet performance and excellent retention of mechanical properties after aging at 400 F for 4000 hours.

  11. Elliptic generation of composite three-dimensional grids about realistic aircraft

    NASA Technical Reports Server (NTRS)

    Sorenson, Reese L.

    1986-01-01

    An elliptic method for generating composite grids about realistic aircraft is presented. A body-conforming grid is first generated about the entire aircraft by the solution of Poisson's differential equation. This grid has relatively coarse spacing, and it covers the entire physical domain. At boundary surfaces, cell size is controlled and cell skewness is nearly eliminated by inhomogeneous terms, which are found automatically by the program. Certain regions of the grid in which high gradients are expected, and which map into rectangular solids in the computational domain, are then designated for zonal refinement. Spacing in the zonal grids is reduced by adding points with a simple, algebraic scheme. Details of the grid-generation method are presented along with results of the present application, a wing/body configuration based on the F-16 fighter aircraft.

  12. Elliptic generation of composite three-dimensional grids about realistic aircraft

    NASA Technical Reports Server (NTRS)

    Sorenson, R. L.

    1986-01-01

    An elliptic method for generating composite grids about realistic aircraft is presented. A body-conforming grid is first generated about the entire aircraft by the solution of Poisson's differential equation. This grid has relatively coarse spacing, and it covers the entire physical domain. At boundary surfaces, cell size is controlled and cell skewness is nearly eliminated by inhomogeneous terms, which are found automatically by the program. Certain regions of the grid in which high gradients are expected, and which map into rectangular solids in the computational domain, are then designated for zonal refinement. Spacing in the zonal grids is reduced by adding points with a simple, algebraic scheme. Details of the grid generation method are presented along with results of the present application, a wing-body configuration based on the F-16 fighter aircraft.

  13. Interim results of long-term environmental exposures of advanced composites for aircraft applications

    NASA Technical Reports Server (NTRS)

    Pride, R. A.

    1978-01-01

    Interim results from a number of ongoing, long-term environmental effects programs for composite materials are reported. The flight service experience is evaluated for 142 composite aircraft components after more than five years and one million successful component flight hours. Ground-based outdoor exposures of composite material coupons after 3 years of exposure at five sites have reached equilibrium levels of moisture pickup which are predictable. Solar ultraviolet-induced material loss is discussed for these same exposures. No significant degradation has been observed in residual strength for either stressed or unstressed specimens, or for exposures to aviation fuels and fluids.

  14. Environmental exposure effects on composite materials for commercial aircraft

    NASA Technical Reports Server (NTRS)

    Gibbons, M. N.

    1982-01-01

    The data base for composite materials' properties as they are affected by the environments encountered in operating conditions, both in flight and at ground terminals is expanded. Absorbed moisture degrades the mechanical properties of graphite/epoxy laminates at elevated temperatures. Since airplane components are frequently exposed to atmospheric moisture, rain, and accumulated water, quantitative data are required to evaluate the amount of fluids absorbed under various environmental conditions and the subsequent effects on material properties. In addition, accelerated laboratory test techniques are developed are reliably capable of predicting long term behavior. An accelerated environmental exposure testing procedure is developed, and experimental results are correlated and compared with analytical results to establish the level of confidence for predicting composite material properties.

  15. Graphite-polyimide composite for application to aircraft engines

    NASA Technical Reports Server (NTRS)

    Hanson, M. P.; Chamis, C. C.

    1974-01-01

    A combined experimental and theoretical investigation was performed in order to (1) demonstrate that high quality angleplied laminates can be made from HT-S/PMR-RI (PMR in situ polymerization of monomeric reactants), (2) characterize the PMR-PI material and to determine the HT-S unidirectional composite properties required for composite micro and macromechanics and laminate analyses, and (3) select HT-S/PMR-PI laminate configurations to meet the general design requirements for high-tip-speed compressor blades. The results of the investigation showed that HT-S/PMR laminate configurations can be fabricated which satisfy the high-tip-speed compressor blade design requirements when operating within the temperature capability of the polymide matrix.

  16. Multifunctional composites aircraft applications in Finmeccanica - Some examples

    NASA Astrophysics Data System (ADS)

    Iannone, Michele

    2016-05-01

    Some examples of multifunctional composite materials presently developed by Finmeccanica are described. The basic concept is to modify the material/structure by adding a further function to the structural basic one. The described examples refer to: improvement of processability; self-diagnostic capability; improvement of the allowables, acting on reduction of the knock down factor required to take in account the environmental ageing effects.

  17. Advanced composite vertical stabilizer for DC-10 transport aircraft

    NASA Technical Reports Server (NTRS)

    Stephens, C. O.

    1978-01-01

    The structural design configuration for the Composite Vertical Stabilizer is described and the structural design, analysis, and weight activities are presented. The status of fabrication and test activities for the development test portion of the program is described. Test results are presented for the skin panels, spar web, spar cap to cover, and laminate properties specimens. Engineering drawings of vertification test panels and root fittings, rudder support specimens, titanium fittings, and rear spar specimen analysis models are included.

  18. Certification of Discontinuous Composite Material Forms for Aircraft Structures

    NASA Astrophysics Data System (ADS)

    Arce, Michael Roger

    New, high performance chopped, discontinuous, or short fiber composites (DFCs), DFCs, such as HexMC and Lytex, made by compression molding of randomly oriented pre-impregnated unidirectional tape, can be formed into complex geometry while retaining mechanical properties suitable for structural use. These DFCs provide the performance benefits of Continuous Fiber Composites (CFCs) in form factors that were previously unavailable. These materials demonstrate some notably different properties from continuous fiber composites, especially with respect to damage tolerance and failure behavior. These behaviors are not very well understood, and fundamental research efforts are ongoing to better characterize the material and to ease certification for future uses. Despite this, these new DFCs show such promise that they are already in service in the aerospace industry, for instance in the Boeing 787. Unfortunately, the relative novelty of these parts means that they needed to be certified by “point design”, an excess of physical testing, rather than by a mix of physical testing and finite element analysis, which would be the case for CFCs or metals. In this study, one particular approach to characterizing both linear-elastic and failure behaviors are considered. The Stochastic Laminate Analogy, which represents a novel approach to modeling DFCs, and its combination with a Ply Discount scheme. Owing to limited available computational resources, only preliminary results are available, but those results are quite promising and warrant further investigation.

  19. Advanced composite aileron for L-1011 transport aircraft: Ground tests and flight evaluation

    NASA Technical Reports Server (NTRS)

    Griffin, C. F.

    1981-01-01

    A composite aileron and a metal aileron were subjected to a series of comparative stiffness and vibration tests. These tests showed that the stiffness and vibration characteristics of the composite aileron are similar to the metal aileron. The first composite ground test article was statically tested to failure which occurred at 139 percent of design ultimate load. The second composite ground test article was tested to verify damage tolerance and fail-safe characteristics. Visible damage was inflicted to the aileron and the aileron was subjected to one lifetime of spectrum fatigue loading. After conducting limit load tests on the aileron, major damage was inflicted to the cover and the aileron was loaded to failure which occurred at 130 percent of design ultimate load. A shipset of composite ailerons were installed on Lockheed's L-1011 flight test aircraft and flown. The composite aileron was flutter-free throughout the flight envelope.

  20. Develop Critical Profilometers to Meet Current and Future Composite Overwrapped Pressure Vessel (COPV) Interior Inspection Needs

    NASA Technical Reports Server (NTRS)

    Saulsberry, Regor L.

    2010-01-01

    The objective of this project is to develop laser profilometer technology that can efficiently inspect and map the inside of composite pressure vessels for flaws such as liner buckling, pitting, or other surface imperfections. The project will also provide profilometers that can directly support inspections of flight vessels during development and qualification programs and subsequently be implemented into manufacturing inspections to screen out vessels with "out of family" liner defects. An example interior scan of a carbon overwrapped bottle is shown in comparison to an external view of the same bottle (Fig. 1). The internal scan is primarily of the cylindrical portion, but extends about 0.15 in. into the end cap area.

  1. Probability of Detection Study on Impact Damage to Honeycomb Composite Structure using Thermographic Inspection

    NASA Technical Reports Server (NTRS)

    Hodge, Andrew J.; Walker, James L., II

    2008-01-01

    A probability of detection study was performed for the detection of impact damage using flash heating infrared thermography on a full scale honeycomb composite structure. The honeycomb structure was an intertank structure from a previous NASA technology demonstration program. The intertank was fabricated from IM7/8552 carbon fiber/epoxy facesheets and aluminum honeycomb core. The intertank was impacted in multiple locations with a range of impact energies utilizing a spherical indenter. In a single blind study, the intertank was inspected with thermography before and after impact damage was incurred. Following thermographic inspection several impact sites were sectioned from the intertank and cross-sectioned for microscopic comparisons of NDE detection and actual damage incurred. The study concluded that thermographic inspection was a good method of detecting delamination damage incurred by impact. The 90/95 confidence level on the probability of detection was close to the impact energy that delaminations were first observed through cross-sectional analysis.

  2. Advanced composite structural concepts and material technologies for primary aircraft structures

    NASA Technical Reports Server (NTRS)

    Jackson, Anthony

    1991-01-01

    Structural weight savings using advanced composites have been demonstrated for many years. Most military aircraft today use these materials extensively and Europe has taken the lead in their use in commercial aircraft primary structures. A major inhibiter to the use of advanced composites in the United States is cost. Material costs are high and will remain high relative to aluminum. The key therefore lies in the significant reduction in fabrication and assembly costs. The largest cost in most structures today is assembly. As part of the NASA Advanced Composite Technology Program, Lockheed Aeronautical Systems Company has a contract to explore and develop advanced structural and manufacturing concepts using advanced composites for transport aircraft. Wing and fuselage concepts and related trade studies are discussed. These concepts are intended to lower cost and weight through the use of innovative material forms, processes, structural configurations and minimization of parts. The approach to the trade studies and the downselect to the primary wing and fuselage concepts is detailed. The expectations for the development of these concepts is reviewed.

  3. Fibre Optic Sensors for Structural Health Monitoring of Aircraft Composite Structures: Recent Advances and Applications.

    PubMed

    Di Sante, Raffaella

    2015-01-01

    In-service structural health monitoring of composite aircraft structures plays a key role in the assessment of their performance and integrity. In recent years, Fibre Optic Sensors (FOS) have proved to be a potentially excellent technique for real-time in-situ monitoring of these structures due to their numerous advantages, such as immunity to electromagnetic interference, small size, light weight, durability, and high bandwidth, which allows a great number of sensors to operate in the same system, and the possibility to be integrated within the material. However, more effort is still needed to bring the technology to a fully mature readiness level. In this paper, recent research and applications in structural health monitoring of composite aircraft structures using FOS have been critically reviewed, considering both the multi-point and distributed sensing techniques. PMID:26263987

  4. Fibre Optic Sensors for Structural Health Monitoring of Aircraft Composite Structures: Recent Advances and Applications

    PubMed Central

    Di Sante, Raffaella

    2015-01-01

    In-service structural health monitoring of composite aircraft structures plays a key role in the assessment of their performance and integrity. In recent years, Fibre Optic Sensors (FOS) have proved to be a potentially excellent technique for real-time in-situ monitoring of these structures due to their numerous advantages, such as immunity to electromagnetic interference, small size, light weight, durability, and high bandwidth, which allows a great number of sensors to operate in the same system, and the possibility to be integrated within the material. However, more effort is still needed to bring the technology to a fully mature readiness level. In this paper, recent research and applications in structural health monitoring of composite aircraft structures using FOS have been critically reviewed, considering both the multi-point and distributed sensing techniques. PMID:26263987

  5. A smart composite patch for the repair of aircraft structures

    NASA Astrophysics Data System (ADS)

    Wakha, Kelah; Samuel, Paul; Pines, Darryll J.

    2005-05-01

    Recent interest in bonded composite patch repair technology for aerospace systems is because this method can be carried out at a reduced cost and time and can easily be applied to complex geometric structures. This paper details the development of a dual stiffness/energy sensor for monitoring the integrity of a composite patch used to repair an aluminum structural component. The smart sensor has the ability to predict the elastic field of a given host structure based on the strain state of two sub-sensors integrated into the structure. The present study shows the possibility of using the sensor to deduce the local instantaneous host stiffness. Damaged structures are characterized by a reduction in their elastic stiffness that evolve from microstructural defects. A local smart sensor can be developed to sense the local average properties on a host. In this paper, sensors are attached to a structure and a modified Eshelby's equivalent inclusion method is used to derive the elastic properties of the host. An analytical derivation and a sensitivity analysis for the quasistatic application is given in a papers by Majed, Dasgupta, Kelah and Pines. A summary of the derivation of the dynamic Eshelby tensor is presented. This is of importance because damage detection in structures undergoing vibratory and other motions present a greater challenge than those in quasistatic motion. An in-situ health monitoring active sensor system for a real structure (an aluminum plate with an attached repair patch) under close-to real lifecycle loading conditions is developed. The detection of the onset of any damage to the structure as well as the repair patch and the subsequent monitoring of the growth of this damage constitute important goals of the system. Both experimental and finite element methods were applied. Experimental results are presented for tests of the aluminum plate with the repair patch under monotonic quasi-static and dynamic loading vibratory conditions. In summary, the

  6. Advanced composite aileron for L-1011 transport aircraft

    NASA Technical Reports Server (NTRS)

    1978-01-01

    Design and evaluation of alternate concepts for the major subcomponents of the advanced composite aileron (ACA) was completed. From this array of subcomponents, aileron assemblies were formulated and evaluated. Based on these analyses a multirib assembly with graphite tape/syntactic core covers, a graphite tape front spar, and a graphite fabric rib was selected for development. A weight savings of 29.1 percent (40.8 pounds per aileron) is predicted. Engineering cost analyses indicate that the production cost of the ACA will be 7.3 percent less than the current aluminum aileron. Fabrication, machining, and testing of the material evaluation specimens for the resin screening program was completed. The test results lead to the selection of Narmco 5208 resin for the ACA. Other activities completed include: the detailed design of the ACA, construction of a three dimensional finite element model for structural analysis, and formulation of detail plans for material verification and process development.

  7. Advanced composite aileron for L-1011 transport aircraft: Aileron manufacture

    NASA Technical Reports Server (NTRS)

    Dunning, E. G.; Cobbs, W. L.; Legg, R. L.

    1981-01-01

    The fabrication activities of the Advanced Composite Aileron (ACA) program are discussed. These activities included detail fabrication, manufacturing development, assembly, repair and quality assurance. Five ship sets of ailerons were manufactured. The detail fabrication effort of ribs, spar and covers was accomplished on male tools to a common cure cycle. Graphite epoxy tape and fabric and syntactic epoxy materials were utilized in the fabrication. The ribs and spar were net cured and required no post cure trim. Material inconsistencies resulted in manufacturing development of the front spar during the production effort. The assembly effort was accomplished in subassembly and assembly fixtures. The manual drilling system utilized a dagger type drill in a hydraulic feed control hand drill. Coupon testing for each detail was done.

  8. Advanced composite aileron for L-1011 transport aircraft, task 1

    NASA Technical Reports Server (NTRS)

    Griffin, C. F.; Fogg, L. D.; Stone, R. L.; Dunning, E. G.

    1978-01-01

    Structural design and maintainability criteria were established and used as a guideline for evaluating a variety of configurations and materials for each of the major subcomponents. From this array of subcomponent designs, several aileron assemblies were formulated and analyzed. The selected design is a multirib configuration with sheet skin covers mechanically fastened to channel section ribs and spars. Qualitative analysis of currently available composite material systems led to the selection of three candidate materials on which comparative structural tests were conducted to measure the effects of environment and impact damage on mechanical property retention. In addition, each system was evaluated for producibility characteristics. From these tests, Thornel 300/5208 unidirectional tape was selected for the front spar and covers, and Thornel 300 fabric/5208 was chosen for the ribs.

  9. Advanced composite elevator for Boeing 727 aircraft. Volume 1: Technical summary

    NASA Technical Reports Server (NTRS)

    Chovil, D. V.; Harvey, S. T.; Mccarty, J. E.; Desper, O. E.; Jamison, E. S.; Syder, H.

    1981-01-01

    The design, development, analysis, and testing activities and results that were required to produce five and one-half shipsets of advanced composite elevators for Boeing 727 aircraft are summarized. During the preliminary design period, alternative concepts were developed. After selection of the best design, detail design and basic configuration improvements were evaluated. Five and one-half shipsets were manufactured. All program goals (except competitive cost demonstration) were accomplished when our design met or exceeded all requirements, criteria, and objectives.

  10. Full-scale testing, production and cost analysis data for the advanced composite stabilizer for Boeing 737 aircraft, volume 2

    NASA Technical Reports Server (NTRS)

    Aniversario, R. B.; Harvey, S. T.; Mccarty, J. E.; Parson, J. T.; Peterson, D. C.; Pritchett, L. D.; Wilson, D. R.; Wogulis, E. R.

    1982-01-01

    The development, testing, production activities, and associated costs that were required to produce five-and-one-half advanced-composite stabilizer shipsets for Boeing 737 aircraft are defined and discussed.

  11. Analytical and experimental investigation of aircraft metal structures reinforced with filamentary composites. Phase 3: Major component development

    NASA Technical Reports Server (NTRS)

    Bryson, L. L.; Mccarty, J. E.

    1973-01-01

    Analytical and experimental investigations, performed to establish the feasibility of reinforcing metal aircraft structures with advanced filamentary composites, are reported. Aluminum-boron-epoxy and titanium-boron-epoxy were used in the design and manufacture of three major structural components. The components were representative of subsonic aircraft fuselage and window belt panels and supersonic aircraft compression panels. Both unidirectional and multidirectional reinforcement concepts were employed. Blade penetration, axial compression, and inplane shear tests were conducted. Composite reinforced structural components designed to realistic airframe structural criteria demonstrated the potential for significant weight savings while maintaining strength, stability, and damage containment properties of all metal components designed to meet the same criteria.

  12. The potential for damage from the accidental release of conductive carbon fibers from aircraft composites

    NASA Technical Reports Server (NTRS)

    Bell, V. L.

    1980-01-01

    Carbon and graphite fibers are known to be electrically conductive. The rapidly accelerating use of carbon fibers as the reinforcement in filamentary composite materials brought up the possibility of accidental release of carbon fibers from the burning of crashed commercial airliners with carbon composite parts. Such release could conceivably cause widespread damage to electrical and electronic equipment. The experimental and analytical results of a comprehensive investigation of the various elements necessary to assess the extent of such potential damage in terms of annual expected costs and maximum losses at low probabilities of occurrence are presented. A review of NASA materials research program to provide alternate or modified composite materials to overcome any electrical hazards from the use of carbon composites in aircraft structures is described.

  13. Critical joints in large composite primary aircraft structures. Volume 2: Technology demonstration test report

    NASA Technical Reports Server (NTRS)

    Bunin, Bruce L.

    1985-01-01

    A program was conducted to develop the technology for critical structural joints in composite wing structure that meets all the design requirements of a 1990 commercial transport aircraft. The results of four large composite multirow bolted joint tests are presented. The tests were conducted to demonstrate the technology for critical joints in highly loaded composite structure and to verify the analytical methods that were developed throughout the program. The test consisted of a wing skin-stringer transition specimen representing a stringer runout and skin splice on the wing lower surface at the side of the fuselage attachment. All tests were static tension tests. The composite material was Toray T-300 fiber with Ciba-Geigy 914 resin in 10 mil tape form. The splice members were metallic, using combinations of aluminum and titanium. Discussions are given of the test article, instrumentation, test setup, test procedures, and test results for each of the four specimens. Some of the analytical predictions are also included.

  14. Flight service evaluation of Kevlar-49 epoxy composite panels in wide-bodied commercial transport aircraft

    NASA Technical Reports Server (NTRS)

    Stone, R. H.

    1979-01-01

    Kevlar-49 fairing panels, installed as flight service components on three L-1011s, were inspected after five years' service. There are six Kevlar-49 panels on each aircraft: a left-hand and right-hand set of a wing-body sandwich fairing; a solid laminate under-wing fillet panel; and a 150 C (300 F) service aft engine fairing. The fairings have accumulated a total of 40,534 hours, with one ship set having 16,091 hours service as of Feb. 11, 1979. The Kevlar-49 components were found to be performing satisfactorily in service with no major problems, or any condition requiring corrective action. The only defects noted were minor impact damage, and a minor degree of fastener hole fraying and elongation. These are for the most part comparable to damage noted on fiberglass fairings.

  15. Energy Finite Element Analysis Developments for Vibration Analysis of Composite Aircraft Structures

    NASA Technical Reports Server (NTRS)

    Vlahopoulos, Nickolas; Schiller, Noah H.

    2011-01-01

    The Energy Finite Element Analysis (EFEA) has been utilized successfully for modeling complex structural-acoustic systems with isotropic structural material properties. In this paper, a formulation for modeling structures made out of composite materials is presented. An approach based on spectral finite element analysis is utilized first for developing the equivalent material properties for the composite material. These equivalent properties are employed in the EFEA governing differential equations for representing the composite materials and deriving the element level matrices. The power transmission characteristics at connections between members made out of non-isotropic composite material are considered for deriving suitable power transmission coefficients at junctions of interconnected members. These coefficients are utilized for computing the joint matrix that is needed to assemble the global system of EFEA equations. The global system of EFEA equations is solved numerically and the vibration levels within the entire system can be computed. The new EFEA formulation for modeling composite laminate structures is validated through comparison to test data collected from a representative composite aircraft fuselage that is made out of a composite outer shell and composite frames and stiffeners. NASA Langley constructed the composite cylinder and conducted the test measurements utilized in this work.

  16. Composition and morphology of particle emissions from in-use aircraft during takeoff and landing.

    PubMed

    Mazaheri, Mandana; Bostrom, Thor E; Johnson, Graham R; Morawska, Lidia

    2013-05-21

    In order to provide realistic data for air pollution inventories and source apportionment at airports, the morphology and composition of ultrafine particles (UFP) in aircraft engine exhaust were measured and characterized. For this purpose, two independent measurement techniques were employed to collect emissions during normal takeoff and landing operations at Brisbane Airport, Australia. PM1 emissions in the airfield were collected on filters and analyzed using the particle-induced X-ray emission (PIXE) technique. Morphological and compositional analyses of individual ultrafine particles in aircraft plumes were performed on silicon nitride membrane grids using transmission electron microscopy (TEM) combined with energy-dispersive X-ray microanalysis (EDX). TEM results showed that the deposited particles were in the range of 5-100 nm in diameter, had semisolid spherical shapes and were dominant in the nucleation mode (18-20 nm). The EDX analysis showed the main elements in the nucleation particles were C, O, S, and Cl. The PIXE analysis of the airfield samples was generally in agreement with the EDX in detecting S, Cl, K, Fe, and Si in the particles. The results of this study provide important scientific information on the toxicity of aircraft exhaust and their impact on local air quality. PMID:23618073

  17. A Portable Ultrasonic Nondestructive Inspection System for Metal Matrix Composite Track Shoes

    NASA Astrophysics Data System (ADS)

    Mi, Bao; Zhao, Xiaoliang; Qian, Tao; Stevenson, Mark; Kwan, Chiman; Owens, Steven E.; Royer, Roger L.; Tittmann, Bernhard R.; Raju, Basavaraju B.

    2007-03-01

    Cast aluminum track shoes reinforced with metal matrix composite (MMC) inserts at heavy loading areas such as center splines and sprocket windows are light in weight, and can resist high temperature and wear. Various defects such as disbonds at the insert-substrate interface, cracks and porosity in the MMC layer, etc. can be introduced during the manufacturing process and/or in service. This paper presents a portable ultrasonic system to automatically inspect tank track shoes for disbond. Ultrasonic pulse/echo inspection has shown good reliability for disbond detection. A prototype sensor array fixture has been designed and fabricated to prove the feasibility. Good agreements between the sensor fixture results and ultrasonic C-scan images were obtained.

  18. A Portable Ultrasonic Nondestructive Inspection System for Metal Matrix Composite Track Shoes

    SciTech Connect

    Mi Bao; Zhao Xiaoliang; Qian Tao; Stevenson, Mark; Kwan, Chiman; Owens, Steven E.; Royer, Roger L. Jr.; Tittmann, Bernhard R.; Raju, Basavaraju B.

    2007-03-21

    Cast aluminum track shoes reinforced with metal matrix composite (MMC) inserts at heavy loading areas such as center splines and sprocket windows are light in weight, and can resist high temperature and wear. Various defects such as disbonds at the insert-substrate interface, cracks and porosity in the MMC layer, etc. can be introduced during the manufacturing process and/or in service. This paper presents a portable ultrasonic system to automatically inspect tank track shoes for disbond. Ultrasonic pulse/echo inspection has shown good reliability for disbond detection. A prototype sensor array fixture has been designed and fabricated to prove the feasibility. Good agreements between the sensor fixture results and ultrasonic C-scan images were obtained.

  19. A 1 kHz A-scan rate pump-probe laser-ultrasound system for robust inspection of composites.

    PubMed

    Pelivanov, Ivan; Shtokolov, Alex; Wei, Chen-Wei; O'Donnell, Matthew

    2015-09-01

    We recently built a fiber-optic laser-ultrasound (LU) scanner for nondestructive evaluation (NDE) of aircraft composites and demonstrated its greatly improved sensitivity and stability compared with current noncontact systems. It is also very attractive in terms of cost, stability to environmental noise and surface roughness, simplicity in adjustment, footprint, and flexibility. A new type of a balanced fiber-optic Sagnac interferometer is a key component of this all-optical LU pump-probe system. Very high A-scan rates can be achieved because no reference arm or stabilization feedback are needed. Here, we demonstrate LU system performance at 1000 A-scans/s combined with a fast 2-D translator operating at a scanning speed of 100 mm/s with a peak acceleration of 10 m/s(2) in both lateral directions to produce parallel B-scans at high rates. The fast scanning strategy is described in detail. The sensitivity of this system, in terms of noise equivalent pressure, was further improved to be only 8.3 dB above the Nyquist thermal noise limit. To our knowledge, this is the best reported sensitivity for a noncontact ultrasonic detector of this dimension used to inspect aircraft composites. PMID:26415130

  20. Critical Joints in Large Composite Primary Aircraft Structures. Volume 3: Ancillary Test Results

    NASA Technical Reports Server (NTRS)

    Bunin, Bruce L.; Sagui, R. L.

    1985-01-01

    A program was conducted to develop the technology for critical structural joints for composite wing structure that meets all the design requirements of a 1990 commercial transport aircraft. The results of a comprehensive ancillary test program are summarized, consisting of single-bolt composite joint specimens tested in a variety of configurations. These tests were conducted to characterize the strength and load deflection properties that are required for multirow joint analysis. The composite material was Toray 300 fiber and Ciba-Geigy 914 resin, in the form of 0.005 and 0.01 inch thick unidirectional tape. Tests were conducted in single and double shear for loaded and unloaded hole configurations under both tensile and compressive loading. Two different layup patterns were examined. All tests were conducted at room temperature. In addition, the results of NASA Standard Toughness Test (NASA RP 1092) are reported, which were conducted for several material systems.

  1. Experimental and Numerical Investigation of Wide Area Blunt Impact Damage to Composite Aircraft Structures

    NASA Astrophysics Data System (ADS)

    Chen, Zhi Ming

    Due to their high performance and weight efficiency, carbon fiber composites are increasingly being used in aircraft primary structure applications. Exposed composite structures (e.g., fuselage lower body) are susceptible accidental impacts by ground service equipment (GSE). The very high mass (over 10,000 kg) of GSE impact can involve high energy (over 1000 J) and thus can induce significant internal damage. Furthermore, the large contact area potentially involved with GSE impact can create significant internal delamination and fiber failure without leaving exterior-visible signs that any damage has occurred. The objectives of the research described herein are to: (1) conduct experimental investigation into the composite aircraft damage caused by GSE impact, (2) examine the small-scale failure modes in focused, element-level studies, (3) establish a finite element modeling methodology involving detailed simulation capability that is validated via small-scale tests, and (4) apply these modeling capabilities to accurately predict full-scale structural behavior without adjustment (e.g., tuning) of modeling input parameters.

  2. High-Temperature, Lightweight, Self-Healing Ceramic Composites for Aircraft Engine Applications

    NASA Technical Reports Server (NTRS)

    Raj, Sai V.; Bhatt, Ramkrishna

    2013-01-01

    The use of reliable, high-temperature, lightweight materials in the manufacture of aircraft engines is expected to result in lower fossil and biofuel consumption, thereby leading to cost savings and lower carbon emissions due to air travel. Although nickel-based superalloy blades and vanes have been successfully used in aircraft engines for several decades, there has been an increased effort to develop high-temperature, lightweight, creep-resistant substitute materials under various NASA programs over the last two decades. As a result, there has been a great deal of interest in developing SiC/SiC ceramic matrix composites (CMCs) due to their higher damage tolerance compared to monolithic ceramics. Current-generation SiC/SiC ceramic matrix composites rely almost entirely on the SiC fibers to carry the load, owing to the premature cracking of the matrix during loading. Thus, the high-temperature usefulness of these CMCs falls well below their theoretical capabilities. The objective of this work is to develop a new class of high-temperature, lightweight, self-healing, SiC fiber-reinforced, engineered matrix ceramic composites.

  3. Evaluation of energy absorption of new concepts of aircraft composite subfloor intersections

    NASA Technical Reports Server (NTRS)

    Jones, Lisa E.; Carden, Huey D.

    1989-01-01

    Forty-one composite aircraft subfloor intersection specimens were tested to determine the effects of geometry and material on the energy absorbing behavior, failure characteristics, and post-crush structural integrity of the specimens. The intersections were constructed of twelve ply + or - 45 sub 6 laminates of either Kevlar 49/934 or AS-4/934 graphite-epoxy in heights of 4, 8, and 12 inches. The geometry of the specimens varied in the designs of the intersection attachment angle. Four different geometries were tested.

  4. Residual stress alleviation of aircraft metal structures reinforced with filamentary composites

    NASA Technical Reports Server (NTRS)

    Kelly, J. B.; June, R. R.

    1973-01-01

    Methods to eliminate or reduce residual stresses in aircraft metal structures reinforced by filamentary composites are discussed. Residual stress level reductions were achieved by modifying the manufacturing procedures used during adhesive bonding. The residual stress alleviation techniques involved various forms of mechanical constraint which were applied to the components during bonding. Nine methods were evaluated, covering a wide range in complexity. All methods investigated during the program affected the residual stress level. In general, residual stresses were reduced by 70 percent or more from the stress level produced by conventional adhesive bonding procedures.

  5. Advanced composites structural concepts and materials technologies for primary aircraft structures: Design/manufacturing concept assessment

    NASA Technical Reports Server (NTRS)

    Chu, Robert L.; Bayha, Tom D.; Davis, HU; Ingram, J. ED; Shukla, Jay G.

    1992-01-01

    Composite Wing and Fuselage Structural Design/Manufacturing Concepts have been developed and evaluated. Trade studies were performed to determine how well the concepts satisfy the program goals of 25 percent cost savings, 40 percent weight savings with aircraft resizing, and 50 percent part count reduction as compared to the aluminum Lockheed L-1011 baseline. The concepts developed using emerging technologies such as large scale resin transfer molding (RTM), automatic tow placed (ATP), braiding, out-of-autoclave and automated manufacturing processes for both thermoset and thermoplastic materials were evaluated for possible application in the design concepts. Trade studies were used to determine which concepts carry into the detailed design development subtask.

  6. Ultrasonic defect evaluation using DGS-diagrams modified for the inspection of anisotropic composite materials

    NASA Astrophysics Data System (ADS)

    Spies, Martin; Rieder, Hans; Dillhöfer, Alexander

    2015-03-01

    The application of DGS-diagrams (Distance-Gain-Size) for defect sizing using ultrasonics is considered for anisotropic materials. Based on far-field formulations for transducers with circular apertures, it is shown that the general DGS-diagram for isotropic materials can be applied to anisotropic media as well, if some modifications in the evaluation are performed. The modified procedure is illustrated and validated using ultrasonic inspection data acquired at a unidirectionally carbon-fiber reinforced composite test block with flat-bottomed holes as model defects.

  7. Large-area thermographic inspection of GRP composite marine vessel hulls

    NASA Astrophysics Data System (ADS)

    Jones, Thomas S.; Berger, Harold; Weaver, Elizabeth

    1993-04-01

    Every year there is an increase in the number of Glass Reinforced Plastic (GRP) composite vessels the Coast Guard inspects. A fast, nondestructive evaluation (NDE) technique is needed to facilitate these inspections. The technique must be suitable for use in field environments. Through a Small Business Innovation Research (SBIR) contract with the Coast Guard R&D Center, Industrial Quality, Inc. has performed a feasibility study evaluating the use of infrared thermography for such applications. The study demonstrated the ability of infrared thermography to detect hidden flaws through a variety of laminates and sandwich panel core materials. Empirical results matched well with analytical results of the sensitivity of the technique to various sizes of discontinuities at different depths. Following the successful SBIR program results, the Coast Guard R&D Center asked IQI to do a survey of the Steam Yacht Medea. The Medea had been repaired by a unique system of laying foam core and fiberglass over the ship's original steel-clad hull. The hybrid steel/foam core/GRP hull provided an additional structural configuration for the infrared thermography inspection equipment to handle.

  8. Recycling process for aircraft plastics and composites. Final report, May-November 1993

    SciTech Connect

    Allred, R.E.; Salas, R.M.

    1995-10-01

    A novel low-temperature catalytic recycling process has been investigated for use in reclaiming plastics and composite materials. The plastics and composites were selected to be representative of those used in Air Force aircraft and munitions. Results show that all types of plastics, thermosets as well as thermoplastics, can be converted in high yields to valuable hydrocarbon products with this novel catalytic conversion process. Conversion times are rapid and the process is closed and, thus, nonpolluting. Additional tests on used plastic blast media, a hazardous waste stream, and composite materials demonstrate the utility of the low-temperature catalytic conversion process. Catalytic conversion of used plastic blast media removed the organic components and reduced the volume of hazardous material by a factor of 5. In that form, the remaining heavy metal oxides can be resmelted, eliminating the hazardous waste stream. Epoxy, polyester, imide, and engineering thermoplastic composite matrices are converted into low molecular weight hydrocarbons leaving valuable fibers behind that can be reused to fabricate additional composite materials. Economic projections show that a recycling plant based on this process will pay for itself in one to two years. A related technology has been demonstrated on a large scale (100 tons/day) for recycling used tires, which shows that there is a high probability for success with large-scale tertiary recycling of plastics and composites.

  9. Large strain variable stiffness composites for shear deformations with applications to morphing aircraft skins

    NASA Astrophysics Data System (ADS)

    McKnight, G. P.; Henry, C. P.

    2008-03-01

    Morphing or reconfigurable structures potentially allow for previously unattainable vehicle performance by permitting several optimized structures to be achieved using a single platform. The key to enabling this technology in applications such as aircraft wings, nozzles, and control surfaces, are new engineered materials which can achieve the necessary deformations but limit losses in parasitic actuation mass and structural efficiency (stiffness/weight). These materials should exhibit precise control of deformation properties and provide high stiffness when exercised through large deformations. In this work, we build upon previous efforts in segmented reinforcement variable stiffness composites employing shape memory polymers to create prototype hybrid composite materials that combine the benefits of cellular materials with those of discontinuous reinforcement composites. These composites help overcome two key challenges for shearing wing skins: the resistance to out of plane buckling from actuation induced shear deformation, and resistance to membrane deflections resulting from distributed aerodynamic pressure loading. We designed, fabricated, and tested composite materials intended for shear deformation and address out of plane deflections in variable area wing skins. Our designs are based on the kinematic engineering of reinforcement platelets such that desired microstructural kinematics is achieved through prescribed boundary conditions. We achieve this kinematic control by etching sheets of metallic reinforcement into regular patterns of platelets and connecting ligaments. This kinematic engineering allows optimization of materials properties for a known deformation pathway. We use mechanical analysis and full field photogrammetry to relate local scale kinematics and strains to global deformations for both axial tension loading and shear loading with a pinned-diamond type fixture. The Poisson ratio of the kinematically engineered composite is ~3x higher than

  10. Modeling and Design Analysis Methodology for Tailoring of Aircraft Structures with Composites

    NASA Technical Reports Server (NTRS)

    Rehfield, Lawrence W.

    2004-01-01

    Composite materials provide design flexibility in that fiber placement and orientation can be specified and a variety of material forms and manufacturing processes are available. It is possible, therefore, to 'tailor' the structure to a high degree in order to meet specific design requirements in an optimum manner. Common industrial practices, however, have limited the choices designers make. One of the reasons for this is that there is a dearth of conceptual/preliminary design analysis tools specifically devoted to identifying structural concepts for composite airframe structures. Large scale finite element simulations are not suitable for such purposes. The present project has been devoted to creating modeling and design analysis methodology for use in the tailoring process of aircraft structures. Emphasis has been given to creating bend-twist elastic coupling in high aspect ratio wings or other lifting surfaces. The direction of our work was in concert with the overall NASA effort Twenty- First Century Aircraft Technology (TCAT). A multi-disciplinary team was assembled by Dr. Damodar Ambur to work on wing technology, which included our project.

  11. Analysis and Testing of a Metallic Repair Applicable to Pressurized Composite Aircraft Structure

    NASA Technical Reports Server (NTRS)

    Przekop, Adam; Jegley, Dawn C.; Rouse, Marshall; Lovejoy, Andrew E.

    2014-01-01

    Development of repair technology is vital to the long-term application of new structural concepts on aircraft structure. The design, analysis, and testing of a repair concept applicable to a stiffened composite panel based on the Pultruded Rod Stitched Efficient Unitized Structure was recently completed. The damage scenario considered was a mid-bay to mid-bay saw-cut with a severed stiffener, flange, and skin. A bolted metallic repair was selected so that it could be easily applied in the operational environment. The present work describes results obtained from tension and pressure panel tests conducted to validate both the repair concept and finite element analysis techniques used in the design effort. Simulation and experimental strain and displacement results show good correlation, indicating that the finite element modeling techniques applied in the effort are an appropriate compromise between required fidelity and computational effort. Static tests under tension and pressure loadings proved that the proposed repair concept is capable of sustaining load levels that are higher than those resulting from the current working stress allowables. Furthermore, the pressure repair panel was subjected to 55,000 pressure load cycles to verify that the design can withstand a life cycle representative for a transport category aircraft. These findings enable upward revision of the stress allowables that had been kept at an overly-conservative level due to concerns associated with repairability of the panels. This conclusion enables more weight efficient structural designs utilizing the composite concept under investigation.

  12. Implementation of CAPIO for Composite Adaptive Control of Cross-Coupled Unstable Aircraft

    NASA Technical Reports Server (NTRS)

    Yildiz, Yildiray; Kolmanovsky, Ilya V.

    2011-01-01

    This paper presents an implementation of a recently developed control allocation algorithm CAPIO (a Control Allocation technique to recover from Pilot Induced Oscillations) for composite adaptive control of an inertially cross coupled unstable aircraft. When actuators are rate-saturated due to either an aggressive pilot command, high gain of the flight control system or some anomaly in the system, the effective delay in the control loop may increase due to the phase shifting between the desired and the achieved system states. This effective time delay may deteriorate the performance or even destabilize the system in some cases, depending on the severity of rate saturation. CAPIO reduces the effective time delay by minimizing the phase shift between the commanded and the actual attitude accelerations. We present simulation results for an unstable aircraft with cross-coupling controlled with a composite adaptive controller in the presence of rate saturation. The simulations demonstrate the potential of CAPIO serving as an effective rate saturation compensator in adverse conditions.

  13. Fuel containment, lightning protection and damage tolerance in large composite primary aircraft structures

    NASA Technical Reports Server (NTRS)

    Griffin, Charles F.; James, Arthur M.

    1985-01-01

    The damage-tolerance characteristics of high strain-to-failure graphite fibers and toughened resins were evaluated. Test results show that conventional fuel tank sealing techniques are applicable to composite structures. Techniques were developed to prevent fuel leaks due to low-energy impact damage. For wing panels subjected to swept stroke lightning strikes, a surface protection of graphite/aluminum wire fabric and a fastener treatment proved effective in eliminating internal sparking and reducing structural damage. The technology features developed were incorporated and demonstrated in a test panel designed to meet the strength, stiffness, and damage tolerance requirements of a large commercial transport aircraft. The panel test results exceeded design requirements for all test conditions. Wing surfaces constructed with composites offer large weight savings if design allowable strains for compression can be increased from current levels.

  14. An overview of the crash dynamics failure behavior of metal and composite aircraft structures

    NASA Technical Reports Server (NTRS)

    Carden, Huey D.; Boitnott, Richard L.; Fasanella, Edwin L.; Jones, Lisa E.

    1991-01-01

    An overview of failure behavior results is presented from some of the crash dynamics research conducted with concepts of aircraft elements and substructure not necessarily designed or optimized for energy absorption or crash loading considerations. Experimental and analytical data are presented that indicate some general trends in the failure behavior of a class of composite structures that includes fuselage panels, individual fuselage sections, fuselage frames, skeleton subfloors with stringers and floor beams without skin covering, and subfloors with skin added to the frame stringer structure. Although the behavior is complex, a strong similarity in the static/dynamic failure behavior among these structures is illustrated through photographs of the experimental results and through analytical data of generic composite structural models.

  15. Rheological Behavior of Composites Based on Carbon Fibers Recycled from Aircraft Waste

    NASA Astrophysics Data System (ADS)

    Marcaníková, Lucie; Hausnerová, Berenika; Kitano, Takeshi

    2009-07-01

    Rheological investigation of composite materials prepared from the recycled aircraft waste materials based on thermoset (epoxy/resin) matrix and long carbon fibers (CF) is presented with the aim of their utilization in consumer industry applications. The carbon fibers recovered via thermal process of pyrolysis were cut into about 150 μm length and melt mixed with thermoplastic matrices based on polypropylene (PP) and polyamide 6 (PA) and various modifiers—ethylene-ethyl acrylate-maleic anhydride (E-EA-MAH), polypropylene grafted maleic anhydride (PP-g-MA) and poly(styrene)-block-poly(ethylene-co-but-1-ene)-block-poly(styrene) (SEBS). Rheological, electrical, mechanical, thermal and morphological results revealed the composites of recycled CF and PP/PP-g-MA as well as PA/E-EA-MAH to be the most promising candidates for new applications.

  16. Low density bismaleimide-carbon microballoon composites. [aircraft and submarine compartment safety

    NASA Technical Reports Server (NTRS)

    Kourtides, D. A.; Parker, J. A. (Inventor)

    1978-01-01

    A process is described for constructing for a composite laminate structure which exhibits a high resistance to heat and flame provides safer interior structures for aircraft and submarine compartments. Composite laminate structures are prepared by the bismaleimide resin preimpregnation of a fiberglass cloth to form a face sheet which is bonded with a bismaleimide hot melt adhesive to a porous core structure selected from the group consisting of polyamide paper and bismaleimide-glass fabric which is filled with carbon microballoons. The carbon microballoons are prepared by pyrolyzing phenolic micro-balloons in the presence of nitrogen. A slurry of the carbon microballoons is prepared to fill the porous core structure. The porous core structure and face sheet are bonded to provide panel structures exhibiting increased mechanical capacities and lower oxygen limit values and smoke density values.

  17. Failure behavior of generic metallic and composite aircraft structural components under crash loads

    NASA Technical Reports Server (NTRS)

    Carden, Huey D.; Robinson, Martha P.

    1990-01-01

    Failure behavior results are presented from crash dynamics research using concepts of aircraft elements and substructure not necessarily designed or optimized for energy absorption or crash loading considerations. To achieve desired new designs incorporating improved energy absorption capabilities often requires an understanding of how more conventional designs behave under crash loadings. Experimental and analytical data are presented which indicate some general trends in the failure behavior of a class of composite structures including individual fuselage frames, skeleton subfloors with stringers and floor beams without skin covering, and subfloors with skin added to the frame-stringer arrangement. Although the behavior is complex, a strong similarity in the static/dynamic failure behavior among these structures is illustrated through photographs of the experimental results and through analytical data of generic composite structural models.

  18. Aeronautics composite material inspection with a terahertz time-domain spectroscopy system

    NASA Astrophysics Data System (ADS)

    Ospald, Frank; Zouaghi, Wissem; Beigang, René; Matheis, Carsten; Jonuscheit, Joachim; Recur, Benoit; Guillet, Jean-Paul; Mounaix, Patrick; Vleugels, Wouter; Bosom, Pablo Venegas; González, Laura Vega; López, Ion; Edo, Rafael Martínez; Sternberg, Yehuda; Vandewal, Marijke

    2014-03-01

    The usability of pulsed broadband terahertz radiation for the inspection of composite materials from the aeronautics industry is investigated, with the goal of developing a mobile time-domain spectroscopy system that operates in reflection geometry. A wide range of samples based on glass and carbon fiber reinforced plastics with various types of defects is examined using an imaging system; the results are evaluated both in time and frequency domain. The conductivity of carbon fibers prevents penetration of the respective samples but also allows analysis of coatings from the reflected THz pulses. Glass fiber composites are, in principle, transparent for THz radiation, but commonly with significant absorption for wavelengths >1 THz. Depending on depth, matrix material, and size, defects like foreign material inserts, delaminations, or moisture contamination can be visualized. If a defect is not too deep in the sample, its location can be correctly identified from the delay between partial reflections at the surface and the defect itself.

  19. Ultrasonic, microwave, and millimeter wave inspection techniques for adhesively bonded stacked open honeycomb core composites

    NASA Astrophysics Data System (ADS)

    Thomson, Clint D.; Cox, Ian; Ghasr, Mohammad Tayeb Ahmed; Ying, Kuang P.; Zoughi, Reza

    2015-03-01

    Honeycomb sandwich composites are used extensively in the aerospace industry to provide stiffness and thickness to lightweight structures. A common fabrication method for thick, curved sandwich structures is to stack and bond multiple honeycomb layers prior to machining core curvatures. Once bonded, each adhesive layer must be inspected for delaminations and the presence of unwanted foreign materials. From a manufacturing and cost standpoint, it can be advantageous to inspect the open core prior to face sheet closeout in order to reduce end-article scrap rates. However, by nature, these honeycomb sandwich composite structures are primarily manufactured from low permittivity and low loss materials making detection of delamination and some of the foreign materials (which also are low permittivity and low loss) quite challenging in the microwave and millimeter wave regime. Likewise, foreign materials such as release film in adhesive layers can be sufficiently thin as to not cause significant attenuation in through-transmission ultrasonic signals, making them difficult to detect. This paper presents a collaborative effort intended to explore the efficacy of different non-contact NDI techniques for detecting flaws in a stacked open fiberglass honeycomb core panel. These techniques primarily included air-coupled through-transmission ultrasonics, single-sided wideband synthetic aperture microwave and millimeter-wave imaging, and lens-focused technique. The goal of this investigation has been to not only evaluate the efficacy of these techniques, but also to determine their unique advantages and limitations for evaluating parameters such as flaw type, flaw size, and flaw depth.

  20. A Study of the Utilization of Advanced Composites in Fuselage Structures of Commercial Aircraft

    NASA Technical Reports Server (NTRS)

    Watts, D. J.; Sumida, P. T.; Bunin, B. L.; Janicki, G. S.; Walker, J. V.; Fox, B. R.

    1985-01-01

    A study was conducted to define the technology and data needed to support the introduction of advanced composites in the future production of fuselage structure in large transport aircraft. Fuselage structures of six candidate airplanes were evaluated for the baseline component. The MD-100 was selected on the basis of its representation of 1990s fuselage structure, an available data base, its impact on the schedule and cost of the development program, and its availability and suitability for flight service evaluation. Acceptance criteria were defined, technology issues were identified, and a composite fuselage technology development plan, including full-scale tests, was identified. The plan was based on composite materials to be available in the mid to late 1980s. Program resources required to develop composite fuselage technology are estimated at a rough order of magnitude to be 877 man-years exclusive of the bird strike and impact dynamic test components. A conceptual composite fuselage was designed, retaining the basic MD-100 structural arrangement for doors, windows, wing, wheel wells, cockpit enclosure, major bulkheads, etc., resulting in a 32 percent weight savings.

  1. A new fiber-optic non-contact compact laser-ultrasound scanner for fast non-destructive testing and evaluation of aircraft composites.

    PubMed

    Pelivanov, Ivan; Buma, Takashi; Xia, Jinjun; Wei, Chen-Wei; O'Donnell, Matthew

    2014-03-21

    Laser ultrasonic (LU) inspection represents an attractive, non-contact method to evaluate composite materials. Current non-contact systems, however, have relatively low sensitivity compared to contact piezoelectric detection. They are also difficult to adjust, very expensive, and strongly influenced by environmental noise. Here, we demonstrate that most of these drawbacks can be eliminated by combining a new generation of compact, inexpensive fiber lasers with new developments in fiber telecommunication optics and an optimally designed balanced probe scheme. In particular, a new type of a balanced fiber-optic Sagnac interferometer is presented as part of an all-optical LU pump-probe system for non-destructive testing and evaluation of aircraft composites. The performance of the LU system is demonstrated on a composite sample with known defects. Wide-band ultrasound probe signals are generated directly at the sample surface with a pulsed fiber laser delivering nanosecond laser pulses at a repetition rate up to 76 kHz rate with a pulse energy of 0.6 mJ. A balanced fiber-optic Sagnac interferometer is employed to detect pressure signals at the same point on the composite surface. A- and B-scans obtained with the Sagnac interferometer are compared to those made with a contact wide-band polyvinylidene fluoride transducer. PMID:24737921

  2. A new fiber-optic non-contact compact laser-ultrasound scanner for fast non-destructive testing and evaluation of aircraft composites

    PubMed Central

    Pelivanov, Ivan; Buma, Takashi; Xia, Jinjun; Wei, Chen-Wei; O'Donnell, Matthew

    2014-01-01

    Laser ultrasonic (LU) inspection represents an attractive, non-contact method to evaluate composite materials. Current non-contact systems, however, have relatively low sensitivity compared to contact piezoelectric detection. They are also difficult to adjust, very expensive, and strongly influenced by environmental noise. Here, we demonstrate that most of these drawbacks can be eliminated by combining a new generation of compact, inexpensive fiber lasers with new developments in fiber telecommunication optics and an optimally designed balanced probe scheme. In particular, a new type of a balanced fiber-optic Sagnac interferometer is presented as part of an all-optical LU pump-probe system for non-destructive testing and evaluation of aircraft composites. The performance of the LU system is demonstrated on a composite sample with known defects. Wide-band ultrasound probe signals are generated directly at the sample surface with a pulsed fiber laser delivering nanosecond laser pulses at a repetition rate up to 76 kHz rate with a pulse energy of 0.6 mJ. A balanced fiber-optic Sagnac interferometer is employed to detect pressure signals at the same point on the composite surface. A- and B-scans obtained with the Sagnac interferometer are compared to those made with a contact wide-band polyvinylidene fluoride transducer. PMID:24737921

  3. Scaled Composites' Proteus aircraft and an F/A-18 Hornet from NASA's Dryden Flight Research Center d

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Scaled Composites' Proteus aircraft and an F/A-18 Hornet from NASA's Dryden Flight Research Center during a low-level flyby at Las Cruces Airport in New Mexico. The unique Proteus aircraft served as a test bed for NASA-sponsored flight tests designed to validate collision-avoidance technologies proposed for uninhabited aircraft. The tests, flown over southern New Mexico in March, 2002, used the Proteus as a surrogate uninhabited aerial vehicle (UAV) while three other aircraft flew toward the Proteus from various angles on simulated collision courses. Radio-based 'detect, see and avoid' equipment on the Proteus successfully detected the other aircraft and relayed that information to a remote pilot on the ground at Las Cruces Airport. The pilot then transmitted commands to the Proteus to maneuver it away from the potential collisions. The flight demonstration, sponsored by NASA Dryden Flight Research Center, New Mexico State University, Scaled Composites, the U.S. Navy and Modern Technology Solutions, Inc., were intended to demonstrate that UAVs can be flown safely and compatibly in the same skies as piloted aircraft.

  4. Evaluation of modal-based damage detection techniques for composite aircraft sandwich structures

    NASA Astrophysics Data System (ADS)

    Oliver, J. A.; Kosmatka, J. B.

    2005-05-01

    Composite sandwich structures are important as structural components in modern lightweight aircraft, but are susceptible to catastrophic failure without obvious forewarning. Internal damage, such as disbonding between skin and core, is detrimental to the structures' strength and integrity and thus must be detected before reaching critical levels. However, highly directional low density cores, such as Nomex honeycomb, make the task of damage detection and health monitoring difficult. One possible method for detecting damage in composite sandwich structures, which seems to have received very little research attention, is analysis of global modal parameters. This study will investigate the viability of modal analysis techniques for detecting skin-core disbonds in carbon fiber-Nomex honeycomb sandwich panels through laboratory testing. A series of carbon fiber prepreg and Nomex honeycomb sandwich panels-representative of structural components used in lightweight composite airframes-were fabricated by means of autoclave co-cure. All panels were of equal dimensions and two were made with predetermined sizes of disbonded areas, created by substituting areas of Teflon release film in place of epoxy film adhesive during the cure. A laser vibrometer was used to capture frequency response functions (FRF) of all panels, and then real and imaginary FRFs at different locations on each plate and operating shapes for each plate were compared. Preliminary results suggest that vibration-based techniques hold promise for damage detection of composite sandwich structures.

  5. Structural Analysis and Optimization of a Composite Fan Blade for Future Aircraft Engine

    NASA Astrophysics Data System (ADS)

    Coroneos, Rula M.; Gorla, Rama Subba Reddy

    2012-09-01

    This paper addresses the structural analysis and optimization of a composite sandwich ply lay-up of a NASA baseline solid metallic fan blade comparable to a future Boeing 737 MAX aircraft engine. Sandwich construction with a polymer matrix composite face sheet and honeycomb aluminum core replaces the original baseline solid metallic fan model made of Titanium. The focus of this work is to design the sandwich composite blade with the optimum number of plies for the face sheet that will withstand the combined pressure and centrifugal loads while the constraints are satisfied and the baseline aerodynamic and geometric parameters are maintained. To satisfy the requirements a sandwich construction for the blade is proposed with composite face sheets and a weak core made of honeycomb aluminum material. For aerodynamic considerations, the thickness of the core is optimized where as the overall blade thickness is held fixed in order not to alter the original airfoil geometry. Weight reduction is taken as the objective function by varying the core thickness of the blade within specified upper and lower bounds. Constraints are imposed on radial displacement limitations and ply failure strength. From the optimum design, the minimum number of plies, which will not fail, is back-calculated. The ply lay-up of the blade is adjusted from the calculated number of plies and final structural analysis is performed. Analyses were carried out by utilizing the OpenMDAO Framework, developed at NASA Glenn Research Center combining optimization with structural assessment.

  6. Structural Analysis and Optimization of a Composite Fan Blade for Future Aircraft Engine

    NASA Technical Reports Server (NTRS)

    Coroneos, Rula M.

    2012-01-01

    This report addresses the structural analysis and optimization of a composite fan blade sized for a large aircraft engine. An existing baseline solid metallic fan blade was used as a starting point to develop a hybrid honeycomb sandwich construction with a polymer matrix composite face sheet and honeycomb aluminum core replacing the original baseline solid metallic fan model made of titanium. The focus of this work is to design the sandwich composite blade with the optimum number of plies for the face sheet that will withstand the combined pressure and centrifugal loads while the constraints are satisfied and the baseline aerodynamic and geometric parameters are maintained. To satisfy the requirements, a sandwich construction for the blade is proposed with composite face sheets and a weak core made of honeycomb aluminum material. For aerodynamic considerations, the thickness of the core is optimized whereas the overall blade thickness is held fixed so as to not alter the original airfoil geometry. Weight is taken as the objective function to be minimized by varying the core thickness of the blade within specified upper and lower bounds. Constraints are imposed on radial displacement limitations and ply failure strength. From the optimum design, the minimum number of plies, which will not fail, is back-calculated. The ply lay-up of the blade is adjusted from the calculated number of plies and final structural analysis is performed. Analyses were carried out by utilizing the OpenMDAO Framework, developed at NASA Glenn Research Center combining optimization with structural assessment.

  7. Weight Assessment for Fuselage Shielding on Aircraft With Open-Rotor Engines and Composite Blade Loss

    NASA Technical Reports Server (NTRS)

    Carney, Kelly; Pereira, Michael; Kohlman, Lee; Goldberg, Robert; Envia, Edmane; Lawrence, Charles; Roberts, Gary; Emmerling, William

    2013-01-01

    The Federal Aviation Administration (FAA) has been engaged in discussions with airframe and engine manufacturers concerning regulations that would apply to new technology fuel efficient "openrotor" engines. Existing regulations for the engines and airframe did not envision features of these engines that include eliminating the fan blade containment systems and including two rows of counter-rotating blades. Damage to the airframe from a failed blade could potentially be catastrophic. Therefore the feasibility of using aircraft fuselage shielding was investigated. In order to establish the feasibility of this shielding, a study was conducted to provide an estimate for the fuselage shielding weight required to provide protection from an open-rotor blade loss. This estimate was generated using a two-step procedure. First, a trajectory analysis was performed to determine the blade orientation and velocity at the point of impact with the fuselage. The trajectory analysis also showed that a blade dispersion angle of 3deg bounded the probable dispersion pattern and so was used for the weight estimate. Next, a finite element impact analysis was performed to determine the required shielding thickness to prevent fuselage penetration. The impact analysis was conducted using an FAA-provided composite blade geometry. The fuselage geometry was based on a medium-sized passenger composite airframe. In the analysis, both the blade and fuselage were assumed to be constructed from a T700S/PR520 triaxially-braided composite architecture. Sufficient test data on T700S/PR520 is available to enable reliable analysis, and also demonstrate its good impact resistance properties. This system was also used in modeling the surrogate blade. The estimated additional weight required for fuselage shielding for a wing- mounted counterrotating open-rotor blade is 236 lb per aircraft. This estimate is based on the shielding material serving the dual use of shielding and fuselage structure. If the

  8. Scanning Ultrasonic Spectroscopy System Developed for the Inspection of Composite Flywheels

    NASA Technical Reports Server (NTRS)

    Martin, Richard E.; Baaklini, George Y.

    2002-01-01

    Composite flywheels are being considered as replacements for chemical batteries aboard the International Space Station. A flywheel stores energy in a spinning mass that can turn a generator to meet power demands. Because of the high rotational speeds of the spinning mass, extensive testing of the flywheel system must be performed prior to flight certification. With this goal in mind, a new scanning system has been developed at the NASA Glenn Research Center for the nondestructive inspection of composite flywheels and flywheel subcomponents. The system uses ultrasonic waves to excite a material and examines the response to detect and locate flaws and material variations. The ultrasonic spectroscopy system uses a transducer to send swept-frequency ultrasonic waves into a test material and then receives the returning signal with a second transducer. The received signal is then analyzed in the frequency domain using a fast Fourier transform. A second fast Fourier transform is performed to examine the spacing of the peaks in the frequency domain. The spacing of the peaks is related to the standing wave resonances that are present in the material because of the constructive and destructive interferences of the waves in the full material thickness as well as in individual layers within the material. Material variations and flaws are then identified by changes in the amplitudes and positions of the peaks in both the frequency and resonance spacing domains. This work, conducted under a grant through the Cleveland State University, extends the capabilities of an existing point-by-point ultrasonic spectroscopy system, thus allowing full-field automated inspection. Results of an ultrasonic spectroscopy scan of a plastic cylinder with intentionally seeded flaws. The result of an ultrasonic spectroscopy scan of a plastic cylinder used as a proof-of-concept specimen is shown. The cylinder contains a number of flat bottomed holes of various sizes and shapes. The scanning system

  9. Rugometric and microtopographic non-invasive inspection in dental-resin composites and zirconia ceramics

    NASA Astrophysics Data System (ADS)

    Fernández-Oliveras, Alicia; Costa, Manuel F. M.; Pecho, Oscar E.; Rubiño, Manuel; Pérez, María. M.

    2013-11-01

    Surface properties are essential for a complete characterization of biomaterials. In restorative dentistry, the study of the surface properties of materials meant to replace dental tissues in an irreversibly diseased tooth is important to avoid harmful changes in future treatments. We have experimentally analyzed the surface characterization parameters of two different types of dental-resin composites and pre-sintered and sintered zirconia ceramics. We studied two shades of both composite types and two sintered zirconia ceramics: colored and uncolored. Moreover, a surface treatment was applied to one specimen of each dental-resin. All the samples were submitted to rugometric and microtopographic non-invasive inspection with the MICROTOP.06.MFC laser microtopographer in order to gather meaningful statistical parameters such as the average roughness (Ra), the root-mean-square deviation (Rq), the skewness (Rsk), and the kurtosis of the surface height distribution (Rku). For a comparison of the different biomaterials, the uncertainties associated to the surface parameters were also determined. With respect to Ra and Rq, significant differences between the composite shades were found. Among the dental resins, the nanocomposite presented the highest values and, for the zirconia ceramics, the pre-sintered sample registered the lowest ones. The composite performance may have been due to cluster-formation variations. Except for the composites with the surface treatment, the sample surfaces had approximately a normal distribution of heights. The surface treatment applied to the composites increased the average roughness and moved the height distribution farther away from the normal distribution. The zirconia-sintering process resulted in higher average roughness without affecting the height distribution.

  10. Testing and Analysis of a Composite Non-Cylindrical Aircraft Fuselage Structure . Part II; Severe Damage

    NASA Technical Reports Server (NTRS)

    Przekop, Adam; Jegley, Dawn C.; Lovejoy, Andrew E.; Rouse, Marshall; Wu, Hsi-Yung T.

    2016-01-01

    The Environmentally Responsible Aviation Project aimed to develop aircraft technologies enabling significant fuel burn and community noise reductions. Small incremental changes to the conventional metallic alloy-based 'tube and wing' configuration were not sufficient to achieve the desired metrics. One airframe concept identified by the project as having the potential to dramatically improve aircraft performance was a composite-based hybrid wing body configuration. Such a concept, however, presented inherent challenges stemming from, among other factors, the necessity to transfer wing loads through the entire center fuselage section which accommodates a pressurized cabin confined by flat or nearly flat panels. This paper discusses a finite element analysis and the testing of a large-scale hybrid wing body center section structure developed and constructed to demonstrate that the Pultruded Rod Stitched Efficient Unitized Structure concept can meet these challenging demands of the next generation airframes. Part II of the paper considers the final test to failure of the test article in the presence of an intentionally inflicted severe discrete source damage under the wing up-bending loading condition. Finite element analysis results are compared with measurements acquired during the test and demonstrate that the hybrid wing body test article was able to redistribute and support the required design loads in a severely damaged condition.

  11. A control method to inspect the compositional authenticity of Minas Frescal cheese by gel electrophoresis.

    PubMed

    Magenis, Renata B; Prudêncio, Elane S; Molognoni, Luciano; Daguer, Heitor

    2014-08-20

    This study introduces a qualitative method to inspect the compositional authenticity of white nonripened cheeses like Minas Frescal, a typical Brazilian cheese, especially when irregular replacement of milk by whey is suspected. A sodium dodecyl sulfate gel electrophoresis (SDS-PAGE) method, followed by image densitometry, was validated. Cheeses were freeze-dried to electrophoresis, and β-lactoglobulin (β-LG) was chosen as the adulteration marker. In gel trypsin digestion followed by matrix assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry provided its identification. Cheeses with a minimum of 14 mg·g(-1) of β-LG are considered to be adulterated. The method shows satisfactory precision with a detection limit of 7 mg·g(-1). Forty-two commercial samples from inspected establishments were then assessed and subjected to cluster analysis. Compliant and noncompliant groups were set with 24 (57%) authentic samples and 18 (43%) adulterated samples, respectively, showing that proper analytical monitoring is required to inhibit this practice. PMID:25096158

  12. The friction and wear of carbon-carbon composites for aircraft brakes

    NASA Astrophysics Data System (ADS)

    Hutton, Toby

    Many carbon-carbon composite aircraft brakes encounter high wear rates during low energy braking operations. The work presented in this thesis addresses this issue, but it also elucidates the microstructural changes and wear mechanisms that take place in these materials during all braking conditions encountered by aircraft brakes. A variety of investigations were conducted using friction and wear testing, as well as examination of wear surfaces and wear debris using OM, SEM, X-RD, TGA and Density Gradient Separation (DOS). Friction and wear tests were conducted on a PAN fibre/CVI matrix carbon-carbon composite (Dunlop) and a pitch fibre/Resin-CVI matrix carbon-carbon composite (Bendix). Extensive testing was undertaken on the Dunlop composites to asses the effects of composite architecture, fibre orientation and heat treatment temperatures on friction and wear. Other friction and wear tests, conducted on the base Dunlop composite, were used to investigate the relative influences of temperature and sliding speed. It was found that the effect of temperature was dominant over composite architecture, fibre orientation and sliding speed in governing the friction and wear performance of the Dunlop composites. The development of bulk temperatures in excess of 110 C by frictional heating resulted in smooth friction and a low wear rate. Reducing heat treatment temperature also reduced the thermal conductivity producing high interface temperatures, low smooth friction coefficients and low wear rates under low energy braking conditions. However, this was at the expense of high oxidative wear rates under higher energy braking conditions. The Bendix composites had lower thermal conductivities than the fully heat treated Dunlop composite and exhibited similar friction and wear behaviour to Dunlop composites heat treated to lower temperatures. Examination of the wear surfaces using OM and SEM revealed particulate or Type I surface debris on wear surfaces tested under low energy

  13. NASA/aircraft industry standard specification for graphite fiber toughened thermoset resin composite material

    NASA Technical Reports Server (NTRS)

    1985-01-01

    A standard specification for a selected class of graphite fiber/toughened thermoset resin matrix material was developed through joint NASA/Aircraft Industry effort. This specification was compiled to provide uniform requirements and tests for qualifying prepreg systems and for acceptance of prepreg batches. The specification applies specifically to a class of composite prepreg consisting of unidirectional graphite fibers impregnated with a toughened thermoset resin that produce laminates with service temperatures from -65 F to 200 F when cured at temperatures below or equal to 350 F. The specified prepreg has a fiber areal weight of 145 g sq m. The specified tests are limited to those required to set minimum standards for the uncured prepreg and cured laminates, and are not intended to provide design allowable properties.

  14. Rapid non-contact inspection of composite ailerons using air-coupled ultrasound

    NASA Astrophysics Data System (ADS)

    Panda, Rabi Sankar; Karpenko, Oleksii; Udpa, Lalita; Haq, Mahmoodul; Rajagopal, Prabhu; Balasubramaniam, Krishnan

    2016-02-01

    This paper demonstrates an approach for rapid non-contact air-coupled ultrasonic inspection of composite ailerons with complex cross-sectional profile including thickness changes, curvature and the presence of a number of stiffeners. Low-frequency plate guided ultrasonic modes are used in B-scan mode for the measurements in pitch-catch mode. Appropriate probe holder angles suitable for generating and receiving lower order guided wave modes are discussed. Different embodiments of the pitch-catch tandem positions along and across stiffener and curved regions of the test sample enable a rapid test campaign capturing the feature-rich sample profile. Techniques to distinguish special features in the stiffener are presented.

  15. Real-Time Impact Visualization Inspection of Aerospace Composite Structures with Distributed Sensors.

    PubMed

    Si, Liang; Baier, Horst

    2015-01-01

    For the future design of smart aerospace structures, the development and application of a reliable, real-time and automatic monitoring and diagnostic technique is essential. Thus, with distributed sensor networks, a real-time automatic structural health monitoring (SHM) technique is designed and investigated to monitor and predict the locations and force magnitudes of unforeseen foreign impacts on composite structures and to estimate in real time mode the structural state when impacts occur. The proposed smart impact visualization inspection (IVI) technique mainly consists of five functional modules, which are the signal data preprocessing (SDP), the forward model generator (FMG), the impact positioning calculator (IPC), the inverse model operator (IMO) and structural state estimator (SSE). With regard to the verification of the practicality of the proposed IVI technique, various structure configurations are considered, which are a normal CFRP panel and another CFRP panel with "orange peel" surfaces and a cutout hole. Additionally, since robustness against several background disturbances is also an essential criterion for practical engineering demands, investigations and experimental tests are carried out under random vibration interfering noise (RVIN) conditions. The accuracy of the predictions for unknown impact events on composite structures using the IVI technique is validated under various structure configurations and under changing environmental conditions. The evaluated errors all fall well within a satisfactory limit range. Furthermore, it is concluded that the IVI technique is applicable for impact monitoring, diagnosis and assessment of aerospace composite structures in complex practical engineering environments. PMID:26184196

  16. Real-Time Impact Visualization Inspection of Aerospace Composite Structures with Distributed Sensors

    PubMed Central

    Si, Liang; Baier, Horst

    2015-01-01

    For the future design of smart aerospace structures, the development and application of a reliable, real-time and automatic monitoring and diagnostic technique is essential. Thus, with distributed sensor networks, a real-time automatic structural health monitoring (SHM) technique is designed and investigated to monitor and predict the locations and force magnitudes of unforeseen foreign impacts on composite structures and to estimate in real time mode the structural state when impacts occur. The proposed smart impact visualization inspection (IVI) technique mainly consists of five functional modules, which are the signal data preprocessing (SDP), the forward model generator (FMG), the impact positioning calculator (IPC), the inverse model operator (IMO) and structural state estimator (SSE). With regard to the verification of the practicality of the proposed IVI technique, various structure configurations are considered, which are a normal CFRP panel and another CFRP panel with “orange peel” surfaces and a cutout hole. Additionally, since robustness against several background disturbances is also an essential criterion for practical engineering demands, investigations and experimental tests are carried out under random vibration interfering noise (RVIN) conditions. The accuracy of the predictions for unknown impact events on composite structures using the IVI technique is validated under various structure configurations and under changing environmental conditions. The evaluated errors all fall well within a satisfactory limit range. Furthermore, it is concluded that the IVI technique is applicable for impact monitoring, diagnosis and assessment of aerospace composite structures in complex practical engineering environments. PMID:26184196

  17. Injection repair of advanced aircraft composites with a high temperature cyanate ester resin

    NASA Astrophysics Data System (ADS)

    Bauer, Amy Elizabeth

    Polymer matrix composites, especially those with carbon fiber reinforcement, are becoming increasingly common in aerospace applications due to their high stiffness to weight ratio, resulting in significant weight and fuel savings on commercial and military aircraft. Despite their excellent properties, carbon fiber composites are often susceptible to damage in the form of delaminations or interlaminar cracking caused by low energy impact or manufacturing defects. Often not easily detectable, delaminations are detrimental to the strength of the composite and can ultimately result in failure of the component. Therefore methods must be developed to repair damaged composites. Injection repair is a procedure that involves injecting a low viscosity resin into the damaged area and subjecting the composite to heat to cure the resin. Currently, injection repairs are rarely used in high temperature applications because of the lack of resins with both low viscosity and high thermal stability. Therefore demonstrating the use of a resin with satisfactory viscosity and Tg requirements would expand the application of injection repairs to more vigorous environments. In the present study, the injection repair method was developed to repair damaged bismaleimide carbon fiber composites that are similar to composites used on several high temperature weapon platforms. Bisphenol E cyanate ester (BECy) was chosen as the injection resin due to having the unique combination of low viscosity and a high glass transition temperature. Cure kinetic studies found an optimum undercure schedule to achieve the maximum T g while avoiding the high temperature postcure. Mechanical and adhesive tests revealed that partially cured BECy had properties superior to that of the fully cured resin. Following the evaluation of the resin, the injection repair procedure and set up were developed. Successful and reproducible repairs were performed on panels pre-damaged through static loading and drop tower impact

  18. A KBE-enabled design framework for cost/weight optimization study of aircraft composite structures

    NASA Astrophysics Data System (ADS)

    Wang, H.; La Rocca, G.; van Tooren, M. J. L.

    2014-10-01

    Traditionally, minimum weight is the objective when optimizing airframe structures. This optimization, however, does not consider the manufacturing cost which actually determines the profit of the airframe manufacturer. To this purpose, a design framework has been developed able to perform cost/weight multi-objective optimization of an aircraft component, including large topology variations of the structural configuration. The key element of the proposed framework is a dedicated knowledge based engineering (KBE) application, called multi-model generator, which enables modelling very different product configurations and variants and extract all data required to feed the weight and cost estimation modules, in a fully automated fashion. The weight estimation method developed in this research work uses Finite Element Analysis to calculate the internal stresses of the structural elements and an analytical composite plate sizing method to determine their minimum required thicknesses. The manufacturing cost estimation module was developed on the basis of a cost model available in literature. The capability of the framework was successfully demonstrated by designing and optimizing the composite structure of a business jet rudder. The study case indicates the design framework is able to find the Pareto optimal set for minimum structural weight and manufacturing costin a very quick way. Based on the Pareto set, the rudder manufacturer is in conditions to conduct both internal trade-off studies between minimum weight and minimum cost solutions, as well as to offer the OEM a full set of optimized options to choose, rather than one feasible design.

  19. Fuel containment and damage tolerance in large composite primary aircraft structures. Phase 2: Testing

    NASA Technical Reports Server (NTRS)

    Sandifer, J. P.; Denny, A.; Wood, M. A.

    1985-01-01

    Technical issues associated with fuel containment and damage tolerance of composite wing structures for transport aircraft were investigated. Material evaluation tests were conducted on two toughened resin composites: Celion/HX1504 and Celion/5245. These consisted of impact, tension, compression, edge delamination, and double cantilever beam tests. Another test series was conducted on graphite/epoxy box beams simulating a wing cover to spar cap joint configuration of a pressurized fuel tank. These tests evaluated the effectiveness of sealing methods with various fastener types and spacings under fatigue loading and with pressurized fuel. Another test series evaluated the ability of the selected coatings, film, and materials to prevent fuel leakage through 32-ply AS4/2220-1 laminates at various impact energy levels. To verify the structural integrity of the technology demonstration article structural details, tests were conducted on blade stiffened panels and sections. Compression tests were performed on undamaged and impacted stiffened AS4/2220-1 panels and smaller element tests to evaluate stiffener pull-off, side load and failsafe properties. Compression tests were also performed on panels subjected to Zone 2 lightning strikes. All of these data were integrated into a demonstration article representing a moderately loaded area of a transport wing. This test combined lightning strike, pressurized fuel, impact, impact repair, fatigue and residual strength.

  20. Flight service evaluation of an advanced composite empennage component on commercial transport aircraft

    NASA Technical Reports Server (NTRS)

    1976-01-01

    The development and flight evaluation of an advanced composite empennage component is presented. The recommended concept for the covers is graphite-epoxy hats bonded to a graphite-epoxy skin. The hat flare-out has been eliminated, instead the hat is continuous into the joint. The recommended concept for the spars is graphite-epoxy caps and a hybrid of Kevlar-49 and graphite-epoxy in the spar web. The spar cap, spar web stiffeners for attaching the ribs, and intermediate stiffeners are planned to be fabricated as a unit. Access hole in the web will be reinforced with a donut type, zero degree graphite-epoxy wound reinforcement. The miniwich design concept in the upper three ribs originally proposed is changed to a graphite-epoxy stiffened solid laminate design concept. The recommended configuration for the lower seven ribs remains as graphite-epoxy caps with aluminum cruciform diagonals. The indicated weight saving for the current advanced composite vertical fin configuration is 20.2% including a 24 lb growth allowance. The project production cost saving is approximately 1% based on a cumulative average of 250 aircraft and including only material, production labor, and quality assurance costs.

  1. The effect of material heterogeneity in curved composite beams for use in aircraft structures

    NASA Technical Reports Server (NTRS)

    Otoole, Brendan J.; Santare, Michael H.

    1992-01-01

    A design tool is presented for predicting the effect of material heterogeneity on the performance of curved composite beams for use in aircraft fuselage structures. Material heterogeneity can be induced during processes such as sheet forming and stretch forming of thermoplastic composites. This heterogeneity can be introduced in the form of fiber realignment and spreading during the manufacturing process causing a gradient in material properties in both the radial and tangential directions. The analysis procedure uses a separate two-dimensional elasticity solution for the stresses in the flanges and web sections of the beam. The separate solutions are coupled by requiring the forces and displacements match at the section boundaries. Analysis is performed for curved beams loaded in pure bending and uniform pressure. The beams can be of any general cross-section such as a hat, T-, I-, or J-beam. Preliminary results show that geometry of the beam dictates the effect of heterogeneity on performance. Heterogeneity plays a much larger role in beams with a small average radius to depth ratio, R/t, where R is the average radius of the beam and t is the difference between the inside and outside radius. Results of the analysis are in the form of stresses and displacements, and they are compared to both mechanics of materials and numerical solutions obtained using finite element analysis.

  2. Unique failure behavior of metal/composite aircraft structural components under crash type loads

    NASA Technical Reports Server (NTRS)

    Carden, Huey D.

    1990-01-01

    Failure behavior results are presented on some of the crash dynamics research conducted with concepts of aircraft elements and substructure which have not necessarily been designed or optimized for energy absorption or crash loading considerations. To achieve desired new designs which incorporate improved energy absorption capabilities often requires an understanding of how more conventional designs behave under crash type loadings. Experimental and analytical data are presented which indicate some general trends in the failure behavior of a class of composite structures which include individual fuselage frames, skeleton subfloors with stringers and floor beams but without skin covering, and subfloors with skin added to the frame-stringer arrangement. Although the behavior is complex, a strong similarity in the static/dynamic failure behavior among these structures is illustrated through photographs of the experimental results and through analytical data of generic composite structural models. It is believed that the thread of similarity in behavior is telling the designer and dynamists a great deal about what to expect in the crash behavior of these structures and can guide designs for improving the energy absorption and crash behavior of such structures.

  3. Design, Evaluation and Experimental Effort Toward Development of a High Strain Composite Wing for Navy Aircraft

    NASA Technical Reports Server (NTRS)

    Bruno, Joseph; Libeskind, Mark

    1990-01-01

    This design development effort addressed significant technical issues concerning the use and benefits of high strain composite wing structures (Epsilon(sub ult) = 6000 micro-in/in) for future Navy aircraft. These issues were concerned primarily with the structural integrity and durability of the innovative design concepts and manufacturing techniques which permitted a 50 percent increase in design ultimate strain level (while maintaining the same fiber/resin system) as well as damage tolerance and survivability requirements. An extensive test effort consisting of a progressive series of coupon and major element tests was an integral part of this development effort, and culminated in the design, fabrication and test of a major full-scale wing box component. The successful completion of the tests demonstrated the structural integrity, durability and benefits of the design. Low energy impact testing followed by fatigue cycling verified the damage tolerance concepts incorporated within the structure. Finally, live fire ballistic testing confirmed the survivability of the design. The potential benefits of combining newer/emerging composite materials and new or previously developed high strain wing design to maximize structural efficiency and reduce fabrication costs was the subject of subsequent preliminary design and experimental evaluation effort.

  4. The stable isotopic composition of molecular hydrogen in the tropopause region probed by the CARIBIC aircraft

    NASA Astrophysics Data System (ADS)

    Batenburg, A. M.; Schuck, T. J.; Baker, A. K.; Zahn, A.; Brenninkmeijer, C. A. M.; Röckmann, T.

    2012-05-01

    More than 450 air samples that were collected in the upper troposphere - lower stratosphere (UTLS) region by the CARIBIC aircraft (Civil Aircraft for the Regular Investigation of the atmosphere Based on an Instrument Container) have been analyzed for molecular hydrogen (H2) mixing ratios (χ(H2)) and H2 isotopic composition (deuterium content, δD). More than 120 of the analyzed samples contained air from the lowermost stratosphere (LMS). These show that χ(H2) does not vary appreciably with O3-derived height above the thermal tropopause (TP), whereas δD does increase with height. The isotope enrichment is caused by H2 production and destruction processes that enrich the stratospheric H2 reservoir in deuterium (D); the exact shapes of the profiles are mainly determined by mixing of stratospheric with tropospheric air. Tight negative correlations are found between δD and the mixing ratios of methane (χ(CH4)) and nitrous oxide (χ(N2O)), as a result of the relatively long lifetimes of these three species. The correlations are described by δD[‰]=-0.35 · χ(CH4)[ppb]+768 and δD[‰]=-1.90· χ(N2O)[ppb]+745. These correlations are similar to previously published results and likely hold globally for the LMS. Samples that were collected from the Indian subcontinent up to 40° N before, during and after the summer monsoon season show no significant seasonal change in χ(H2), but δD is up to 12.3‰ lower in the July, August and September monsoon samples. This δD decrease is correlated with the χ(CH4) increase in these samples. The significant correlation with χ(CH4) and the absence of a perceptible χ(H2) increase that accompanies the δD decrease indicates that microbial production of very D-depleted H2 in the wet season may contribute to this phenomenon. Some of the samples have very high χ(H2) and very low δD values, which indicates a pollution effect. Aircraft engine exhaust plumes are a suspected cause, since the effect mostly occurs in samples

  5. The stable isotopic composition of molecular hydrogen in the tropopause region probed by the CARIBIC aircraft

    NASA Astrophysics Data System (ADS)

    Batenburg, A. M.; Schuck, T. J.; Baker, A. K.; Zahn, A.; Brenninkmeijer, C. A. M.; Röckmann, T.

    2012-01-01

    More than 450 air samples that were collected in the upper troposphere - lower stratosphere (UTLS) region around the tropopause (TP) by the CARIBIC aircraft (Civil Aircraft for the Regular Investigation of the Atmosphere Based on an Instrument Container) have been analyzed for molecular hydrogen (H2) mixing ratios (m(H2)) and H2 isotopic composition (deuterium content, δD). More than 120 of the analysed samples consisted of air from the lowermost stratosphere (LMS). These show that m(H2) does not vary appreciably with O3-derived height above the thermal TP, whereas δD does increase with height. The isotope enrichment is caused by competing H2 production and destruction processes that enrich the stratospheric H2 reservoir in deuterium (D); the exact shapes of the profiles are mainly determined by mixing of stratospheric with tropospheric air. Tight negative correlations are found between δD and the mixing ratios of methane (CH4) and nitrous oxide (N2O), as a result of the relatively long lifetimes of these three species. The correlations are described by δ D [‰]=-0.35 · m(CH4)[ppb]+768 and δD [‰]=-1.90 · m(N2O)[ppb]+745. These correlations are similar to previously published results and likely hold globally. Samples that were collected from the Indian subcontinent up to 40° N before, during and after the summer monsoon season show no significant seasonal change in m(H2), but δD is up to 15‰ lower in the July, August and September monsoon samples. This δD lowering is correlated with m(CH4) increase. The significant correlation with m(CH4) and the absence of a perceptible m(H2) increase that accompanies the δD lowering indicates that microbial production of very D-depleted H2 in the wet season may contribute to this phenomenon. Some of the samples have very high m(H2) and very low δD values, which indicates a pollution effect. Aircraft engine exhaust plumes are a suspected cause, since the effect mostly occurs in samples collected close to airports

  6. Insights into Submicron Aerosol Composition and Sources from the WINTER Aircraft Campaign Over the Eastern US.

    NASA Astrophysics Data System (ADS)

    Schroder, J. C.; Campuzano Jost, P.; Day, D. A.; Fibiger, D. L.; McDuffie, E. E.; Blake, N. J.; Hills, A. J.; Hornbrook, R. S.; Apel, E. C.; Weinheimer, A. J.; Campos, T. L.; Brown, S. S.; Jimenez, J. L.

    2015-12-01

    The WINTER aircraft campaign was a recent field experiment to probe the sources and evolution of gas pollutants and aerosols in Northeast US urban and industrial plumes during the winter. A highly customized Aerodyne aerosol mass spectrometer (AMS) was flown on the NCAR C-130 to characterize submicron aerosol composition and evolution. Thirteen research flights were conducted covering a wide range of conditions, including rural, urban, and marine environments during day and night. Organic aerosol (OA) was a large component of the submicron aerosol in the boundary layer. The fraction of OA (fOA) was smaller (35-40%) than in recent US summer campaigns (~60-70%). Biomass burning was observed to be an important source of OA in the boundary layer, which is consistent with recent wintertime studies that show a substantial contribution of residential wood burning to the OA loadings. OA oxygenation (O/C ratio) shows a broad distribution with a substantial fraction of smaller O/C ratios when compared to previous summertime campaigns. Since measurements were rarely made very close to primary sources (i.e. directly above urban areas), this is consistent with oxidative chemistry being slower during winter. SOA formation and aging in the NYC plume was observed during several flights and compared with summertime results from LA (CalNex) and Mexico City (MILAGRO). Additionally, an oxidation flow reactor (OFR) capable of oxidizing ambient air up to several equivalent days of oxidation was deployed for the first time in an aircraft platform. The aerosol outflow of the OFR was sampled with the AMS to provide real-time snapshots of the potential for aerosol formation and aging. For example, a case study of a flight through the Ohio River valley showed evidence of oxidation of SO2 to sulfate. The measured sulfate enhancements were in good agreement with our OFR chemical model. OFR results for SOA will be discussed.

  7. Nonlinear Finite Element Analysis of a Composite Non-Cylindrical Pressurized Aircraft Fuselage Structure

    NASA Technical Reports Server (NTRS)

    Przekop, Adam; Wu, Hsi-Yung T.; Shaw, Peter

    2014-01-01

    The Environmentally Responsible Aviation Project aims to develop aircraft technologies enabling significant fuel burn and community noise reductions. Small incremental changes to the conventional metallic alloy-based 'tube and wing' configuration are not sufficient to achieve the desired metrics. One of the airframe concepts that might dramatically improve aircraft performance is a composite-based hybrid wing body configuration. Such a concept, however, presents inherent challenges stemming from, among other factors, the necessity to transfer wing loads through the entire center fuselage section which accommodates a pressurized cabin confined by flat or nearly flat panels. This paper discusses a nonlinear finite element analysis of a large-scale test article being developed to demonstrate that the Pultruded Rod Stitched Efficient Unitized Structure concept can meet these challenging demands of the next generation airframes. There are specific reasons why geometrically nonlinear analysis may be warranted for the hybrid wing body flat panel structure. In general, for sufficiently high internal pressure and/or mechanical loading, energy related to the in-plane strain may become significant relative to the bending strain energy, particularly in thin-walled areas such as the minimum gage skin extensively used in the structure under analysis. To account for this effect, a geometrically nonlinear strain-displacement relationship is needed to properly couple large out-of-plane and in-plane deformations. Depending on the loading, this nonlinear coupling mechanism manifests itself in a distinct manner in compression- and tension-dominated sections of the structure. Under significant compression, nonlinear analysis is needed to accurately predict loss of stability and postbuckled deformation. Under significant tension, the nonlinear effects account for suppression of the out-of-plane deformation due to in-plane stretching. By comparing the present results with the previously

  8. The Effects of Temperature, Humidity and Aircraft Fluid Exposure on T800H/3900-2 Composites Bonded with AF-555M Adhesive

    NASA Technical Reports Server (NTRS)

    Miner, Gilda A.; Hou, Tan-Hung; Lowther, Sharon E.; Thibeault, Sheila A.; Connell, John W.; Blasini, Sheila Roman

    2010-01-01

    Fiber reinforced resin matrix composites and structural adhesives have found increased usage on commercial and military aircraft in recent years. Due to the lack of service history of these relatively new material systems, their long-term aging performance has not been well established. In this study, single lap shear specimens (SLS) were fabricated by secondary bonding of Scotch-Weld(TradeMark) AF-555M between pre-cured adherends comprised of T800H/3900-2 uni-directional laminates. The adherends were co-cured with wet peel-ply for surface preparation. Each bond-line of the SLS specimen was measured to determine thickness and inspected visually using an optical microscope for voids. A three-year environmental aging plan for the SLS specimens at 82 C (180 F) and 85% relative humidity was initiated. SLS strengths were measured for both controls and aged specimens at room temperature and 82 C. The effect of this exposure on lap shear strength and failure modes to date is reported. In addition, the effects of water, saline water, deicing fluid, JP-5 jet fuel and hydraulic fluid on both the composite material and the adhesive bonds were investigated. The up to date results on the effects of these exposures will be discussed.

  9. Dhaksha, the Unmanned Aircraft System in its New Avatar-Automated Aerial Inspection of INDIA'S Tallest Tower

    NASA Astrophysics Data System (ADS)

    Kumar, K. S.; Rasheed, A. Mohamed; Krishna Kumar, R.; Giridharan, M.; Ganesh

    2013-08-01

    DHAKSHA, the unmanned aircraft system (UAS), developed after several years of research by Division of Avionics, Department of Aerospace Engineering, MIT Campus of Anna University has recently proved its capabilities during May 2012 Technology demonstration called UAVforge organised by Defence Research Project Agency, Department of Defence, USA. Team Dhaksha with its most stable design outperformed all the other contestants competing against some of the best engineers from prestigi ous institutions across the globe like Middlesex University from UK, NTU and NUS from Singapore, Tudelft Technical University, Netherlands and other UAV industry participants in the world's toughest UAV challenge. This has opened up an opportunity for Indian UAVs making a presence in the international scenario as well. In furtherance to the above effort at Fort Stewart military base at Georgia,USA, with suitable payloads, the Dhaksha team deployed the UAV in a religious temple festival during November 2012 at Thiruvannamalai District for Tamil Nadu Police to avail the instant aerial imagery services over the crowd of 10 lakhs pilgrims and also about the investigation of the structural strength of the India's tallest structure, the 300 m RCC tower during January 2013. The developed system consists of a custom-built Rotary Wing model with on-board navigation, guidance and control systems (NGC) and ground control station (GCS), for mission planning, remote access, manual overrides and imagery related computations. The mission is to fulfill the competition requirements by using an UAS capable of providing complete solution for the stated problem. In this work the effort to produce multirotor unmanned aerial systems (UAS) for civilian applications at the MIT, Avionics Laboratory is presented

  10. Bonded composite to metal scarf joint performance in an aircraft landing gear drag strut. [for Boeing 747 aircraft

    NASA Technical Reports Server (NTRS)

    Howell, W. E.

    1974-01-01

    The structural performance of a boron-epoxy reinforced titanium drag strut, which contains a bonded scarf joint and was designed to the criteria of the Boeing 747 transport, was evaluated. An experimental and analytical investigation was conducted. The strut was exposed to two lifetimes of spectrum loading and was statically loaded to the tensile and compressive design ultimate loads. Throughout the test program no evidence of any damage in the drag strut was detected by strain gage measurements, ultrasonic inspection, or visual observation. An analytical study of the bonded joint was made using the NASA structural analysis computer program NASTRAN. A comparison of the strains predicted by the NASTRAN computer program with the experimentally determined values shows excellent agreement. The NASTRAN computer program is a viable tool for studying, in detail, the stresses and strains induced in a bonded joint.

  11. Nondestructive Characterization of Composite Materials

    NASA Technical Reports Server (NTRS)

    Bar-Cohen, Y.

    1993-01-01

    Increasingly, composite materials are applied to fracture-critical structures of aircraft and spacecraft...Ultrasonics offer the most capable inspection technology and recently developed techniques appear to improve this technology significantly... Recent progress in ultrasonic NDE of composites will be reviewed.

  12. Mechanical testing and modelling of carbon-carbon composites for aircraft disc brakes

    NASA Astrophysics Data System (ADS)

    Bradley, Luke R.

    The objective of this study is to improve the understanding of the stress distributions and failure mechanisms experienced by carbon-carbon composite aircraft brake discs using finite element (FE) analyses. The project has been carried out in association with Dunlop Aerospace as an EPSRC CASE studentship. It therefore focuses on the carbon-carbon composite brake disc material produced by Dunlop Aerospace, although it is envisaged that the approach will have broader applications for modelling and mechanical testing of carbon-carbon composites in general. The disc brake material is a laminated carbon-carbon composite comprised of poly(acrylonitrile) (PAN) derived carbon fibres in a chemical vapour infiltration (CVI) deposited matrix, in which the reinforcement is present in both continuous fibre and chopped fibre forms. To pave the way for the finite element analysis, a comprehensive study of the mechanical properties of the carbon-carbon composite material was carried out. This focused largely, but not entirely, on model composite materials formulated using structural elements of the disc brake material. The strengths and moduli of these materials were measured in tension, compression and shear in several orientations. It was found that the stress-strain behaviour of the materials were linear in directions where there was some continuous fibre reinforcement, but non-linear when this was not the case. In all orientations, some degree of non-linearity was observed in the shear stress-strain response of the materials. However, this non-linearity was generally not large enough to pose a problem for the estimation of elastic moduli. Evidence was found for negative Poisson's ratio behaviour in some orientations of the material in tension. Additionally, the through-thickness properties of the composite, including interlaminar shear strength, were shown to be positively related to bulk density. The in-plane properties were mostly unrelated to bulk density over the range of

  13. Development of realistic flaw standards for thermographic inspection qualification of composite structures

    SciTech Connect

    Walker, J.L.; Workman, G.L.; Russell, S.S.

    1996-12-31

    Infrared thermographic nondestructive evaluation provides a method for identifying delamination and disbond type defects in advanced composite structures. The thermographic inspection process often involves the concurrent evaluation of a defect calibration standard to ensure that all critically sized flaws will be detected. The calibration standard is constructed in a similar manner as the component to be evaluated, except that artificial flaws are built into the laminate at predetermined locations. These artificial flaws, unbonded regions for this work, are often formed by inserting foreign material such as Teflon tape or bagging film into the laminate as it is fabricated. This method is appropriate if the component has tape or film insert flaws as a result of some manufacturing error, but if not, the question arises; Can thermography find real defects or damage? Several alternative fabrication methods are compared and contrasted for developing in a controlled fashion, defects that could be found in actual structures resulting from mishandling or manufacturing errors. Both monolithic and honeycomb graphite/epoxy panels are constructed with built in voids to simulated various degrees of disbond and delamination type flaws.

  14. Habitat Inspection Scanner, Bio-Structure Scanner, and In Situ Sub-Surface Composition Sensor

    NASA Technical Reports Server (NTRS)

    VanSteenberg, Michael

    2004-01-01

    The extension of dielectric and inductive spectroscopy into in situ observations represents a significant exploration-enabling tool. This technology can be widely applied from microscopic to macroscopic. Dielectrometry and inductometry can measure sub-surface composition and its distribution. The primary environment that we cannot easily explored is the sub-surface of solid bodies. Weather as part of our equipment that we bring with us, or the locations we are exploring. These fundamental questions lie at the core of the exploration Initiative. To answer them we must use a whole host of complimentary tools including those that allow us to practically examine the sub-surface environment. A nondestructive approach offers significant advantages for both the initial identification of likely samples but also the monitoring of ecosystems and crew health. These include materials characterization, nondestructive inspection, and process quality control, damage monitoring, and hidden object detection and identification. The identification of natural resources such as water on the Moon or Mars is of great importance to the utilization of local resource in the support of human exploration crews. On the macroscopic scale, the understanding of what resources are available and how they are distributed is of primary importance to their productive utilization. Even if initial explorations do not require the use of local resources to succeed, eventual settlement and commercial development will. The routine examination of the structural integrity (micro cracks, leaks) of hi.inafi habitats in harsh envkmments ww!d also be enabled.

  15. Durability and damage tolerance of Large Composite Primary Aircraft Structure (LCPAS)

    NASA Technical Reports Server (NTRS)

    Mccarty, John E.; Roeseler, William G.

    1984-01-01

    Analysis and testing addressing the key technology areas of durability and damage tolerance were completed for wing surface panels. The wing of a fuel-efficient, 200-passenger commercial transport airplane for 1990 delivery was sized using graphite-epoxy materials. Coupons of various layups used in the wing sizing were tested in tension, compression, and spectrum fatigue with typical fastener penetrations. The compression strength after barely visible impact damage was determined from coupon and structural element tests. One current material system and one toughened system were evaluated by coupon testing. The results of the coupon and element tests were used to design three distinctly different compression panels meeting the strength, stiffness, and damage-tolerance requirements of the upper wing panels. These three concepts were tested with various amounts of damage ranging from barely visible impact to through-penetration. The results of this program provide the key technology data required to assess the durability and damage-tolerance capability or advanced composites for use in commercial aircraft wing panel structure.

  16. Effect of temperature on composite sandwich structures subjected to low velocity impact. [aircraft construction materials

    NASA Technical Reports Server (NTRS)

    Sharma, A. V.

    1980-01-01

    The effect of low velocity projectile impact on sandwich-type structural components was investigated. The materials used in the fabrication of the impact surface were graphite-, Kevlar-, and boron-fibers with appropriate epoxy matrices. The testing of the specimens was performed at moderately low- and high-temperatures as well as at room temperature to assess the impact-initiated strength degradation of the laminates. Eleven laminates with different stacking sequences, orientations, and thicknesses were tested. The low energy projectile impact is considered to simulate the damage caused by runway debris, the dropping of the hand tools during servicing, etc., on the secondary aircraft structures fabricated with the composite materials. The results show the preload and the impact energy combinations necessary to cause catastrophic failure in the laminates tested. A set of faired curves indicating the failure thresholds is shown separately for the tension-and compression-loaded laminates. The specific-strengths and -modulii for the various laminates tested are also given.

  17. Impact imaging of aircraft composite structure based on a model-independent spatial-wavenumber filter.

    PubMed

    Qiu, Lei; Liu, Bin; Yuan, Shenfang; Su, Zhongqing

    2016-01-01

    The spatial-wavenumber filtering technique is an effective approach to distinguish the propagating direction and wave mode of Lamb wave in spatial-wavenumber domain. Therefore, it has been gradually studied for damage evaluation in recent years. But for on-line impact monitoring in practical application, the main problem is how to realize the spatial-wavenumber filtering of impact signal when the wavenumber of high spatial resolution cannot be measured or the accurate wavenumber curve cannot be modeled. In this paper, a new model-independent spatial-wavenumber filter based impact imaging method is proposed. In this method, a 2D cross-shaped array constructed by two linear piezoelectric (PZT) sensor arrays is used to acquire impact signal on-line. The continuous complex Shannon wavelet transform is adopted to extract the frequency narrowband signals from the frequency wideband impact response signals of the PZT sensors. A model-independent spatial-wavenumber filter is designed based on the spatial-wavenumber filtering technique. Based on the designed filter, a wavenumber searching and best match mechanism is proposed to implement the spatial-wavenumber filtering of the frequency narrowband signals without modeling, which can be used to obtain a wavenumber-time image of the impact relative to a linear PZT sensor array. By using the two wavenumber-time images of the 2D cross-shaped array, the impact direction can be estimated without blind angle. The impact distance relative to the 2D cross-shaped array can be calculated by using the difference of time-of-flight between the frequency narrowband signals of two different central frequencies and the corresponding group velocities. The validations performed on a carbon fiber composite laminate plate and an aircraft composite oil tank show a good impact localization accuracy of the model-independent spatial-wavenumber filter based impact imaging method. PMID:26253754

  18. Biogenic Contributions to Summertime Arctic Aerosol: Observations of Aerosol Composition from the Netcare 2014 Aircraft Campaign

    NASA Astrophysics Data System (ADS)

    Willis, M. D.; Burkart, J.; Koellner, F.; Schneider, J.; Bozem, H.; Hoor, P. M.; Brauner, R.; Herber, A. B.; Leaitch, W. R.; Abbatt, J.

    2014-12-01

    The Arctic is a complex and poorly studied aerosol environment, impacted by strong anthropogenic contributions during winter months and by regional sources in cleaner summer months. In order to gain a predictive understanding of the changing climate in this region, it is necessary to understand the balance between these two aerosol sources to clarify how aerosol might be altered by or contribute to climate change. We present results of vertically resolved, submicron aerosol composition from an Aerodyne high-resolution aerosol mass spectrometer (AMS) during the NETCARE 2014 Polar6 aircraft campaign. The campaign was based in the high Arctic, at Resolute, NU (74°N), allowing measurements from 60 to 2900 meters over ice, open water and near the ice-edge. Concurrent measurements aboard the Polar6 included ultrafine and accumulation mode particle number and size, cloud condensation nuclei concentrations, trace gas concentrations and single particle composition. Aerosol vertical profiles measured by the AMS can be broadly characterized into two regimes corresponding to different meteorological conditions: the first with very low aerosol loading (<0.1 μg/m3) at low altitudes compared to that aloft and high numbers of nucleation mode particles, and the second with higher concentrations at lower levels. This second regime was associated with low concentrations of nucleation mode particles, and higher observable levels of methane sulphonic acid (MSA) from AMS measurements at low altitudes. MSA, produced during the oxidation of dimethyl sulphide, is a marker for the contribution of ocean-derived biogenic sulphur to particulate sulphur and could be identified and quantified using the high-resolution AMS. MSA to sulphate ratios were observed to increase towards lower altitudes, suggesting a contribution to aerosol loading from the ocean. In addition, we present measurements of aerosol neutralization and the characteristics of organic aerosol that relate to the growth of

  19. Microsensors and MEMS for health monitoring of composite and aircraft structures in flight

    NASA Astrophysics Data System (ADS)

    Varadan, Vijay K.; Varadan, Vasundara V.

    1999-07-01

    Microsensors and Microelectromechanical Systems (MEMS) are currently being applied to the structural health monitoring of critical aircraft components. The approach integrates acoustic emission, strain gauges, MEMS accelerometers and vibration monitoring devices with signal processing electronics to provide real-time indicators of incipient failure of aircraft components with a known history of catastrophic failure due to fracture.

  20. Entropy based design and topology optimization for multifunctional composite aircraft skins

    NASA Astrophysics Data System (ADS)

    Ahlers, Kristopher Henry Otto

    The research presented in this dissertation investigates the design methodology of a new integrated radar aircraft skin, which serves a multifunctional role by accommodating structural and thermal loads. Mechanically the skin must be capable of handling tensile and shear loads. The Entropy Generation Minimization (EGM) method is applied to the multifunctional aircraft skin in order to provide a thermodynamic metric for the analysis of different skin material systems. Thermoelectric (TE) devices, sandwiched between the skin and the radar devices for the purpose of harvesting some of the waste heat to be rejected to the ambient, are considered in the analysis. The optimal entropy generation configuration is one that corresponds to the maximum energy harvesting condition, while satisfying tensile and shear running loads. This optimal condition is found to be when the skin is at its thinnest, with a maximum of 65% volume fraction of carbon fiber inclusions. Additionally it is shown that despite increasing the mass of the skin, the overall mission entropy generated decreases. A topology optimization technique is used to determine the optimal material distribution within the multifunctional skin composite at the 65% volume fraction of inclusion material. A three-dimensional design space is created in which thermal and mechanical loads are applied, and optimized using the Solid Isotropic Microstructures with Penalization (SIMP) method. A weighting variable is introduced to allow for scaling of the incident loads, such that either the thermal or mechanical loading condition may be the dominant load affecting the design space. A thermal dominant loading condition produces a topology representative of a domed structure. A mechanically dominate load results in a 'truss' shaped structure. Novel topologies between these two extreme solutions are realized and presented. Materials research was conducted on carbon foams to assess their viability as a multifunctional skin material

  1. Spiral Passive Electromagnetic Sensor (SPES) for composite structural changes in aircraft structures

    NASA Astrophysics Data System (ADS)

    Iervolino, Onorio; Meo, Michele

    2016-04-01

    A major goal of structural health monitoring (SHM) is to provide accurate and responsive detection and monitoring of flaws. This research work reports an investigation of SPES sensors for damage detection, investigating different sensor sizes and how they affect the sensor's signal. A sensor able to monitor structural change that can be remotely interrogated and does not need a power supply is presented in this work. The SPES-sensor presents the great advantage of monitoring conductive and non-conductive structures such as fiberglass-reinforced composites (FRC) and carbon fiber-reinforced polymers (CFRP). Any phenomena that affect the magnetic field of the SPES can be detected and monitored. A study was conducted to investigate the capability of sensor to give information on structural changes, simulated by the presence of an external mass placed in the proximity of sensor. Effect of different positions of the SPES within the sample, and how to extend the area of inspection using multiple sensors was investigated. The sensor was tested embedded in the samples, simulating the structural change on both sides of the sample. In both configurations the sensor described herein demonstrated a great potential to monitor structural changes.

  2. 14 CFR 33.93 - Teardown inspection.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Teardown inspection. 33.93 Section 33.93 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: AIRCRAFT ENGINES Block Tests; Turbine Aircraft Engines § 33.93 Teardown inspection. (a)...

  3. 14 CFR 33.93 - Teardown inspection.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Teardown inspection. 33.93 Section 33.93 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: AIRCRAFT ENGINES Block Tests; Turbine Aircraft Engines § 33.93 Teardown inspection. (a)...

  4. 14 CFR 33.93 - Teardown inspection.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Teardown inspection. 33.93 Section 33.93 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: AIRCRAFT ENGINES Block Tests; Turbine Aircraft Engines § 33.93 Teardown inspection. (a)...

  5. An assessment of tailoring of lightning protection design requirements for a composite wing structure on a metallic aircraft

    NASA Technical Reports Server (NTRS)

    Harwood, T. L.

    1991-01-01

    The Navy A-6E aircraft is presently being modified with a new wing which uses graphite/epoxy structures and substructures around a titanium load-bearing structure. The ability of composites to conduct electricity is less than that of aluminum. This is cause for concern when the wing may be required to conduct large lightning currents. The manufacturer attempted to solve lightning protection issues by performing a risk assessment based on a statistical approach which allows relaxation of the wing lightning protection design levels over certain locations of the composite wing. A sensitivity study is presented designed to define the total risk of relaxation of the design levels.

  6. Infrared aircraft measurements of stratospheric composition over Antarctica during September 1987

    NASA Technical Reports Server (NTRS)

    Toon, Goeff C.; Farmer, C. B.; Lowes, L. L.; Schaper, P. W.; Blavier, J.-F.; Norton, R. H.

    1988-01-01

    The JPL Mark IV interferometer recorded high resolution, infared solar spectra from the NASA DC-8 aircraft during flights over Antarctica in September 1987. The atmospheric absorption features in these spectra were analyzed to determine the overburdens of O3, NO, NO2, HNO3, ClONO2, HCl, HF, CH4, N2O, CO, H2O and CFC-12. The spectra were obtained at latitudes which ranged between 64 degrees S and 86 degrees S, allowing the composition in the interior of the polar vortex to be compared with that at the edge. The latitude dependence observed for NO, HO2, HNO3, ClONO2, HCl and HF are summerized. The values at 30 deg S were observed on the ferry flight from New Zealand to Hawaii. The dashed lines connecting the two were interpolated across the region for which there are no measurements. The chemically perturbed region is seen to consist of a collar of high HNO3 and ClONO2 surrounding a core in which the overburdens of these and of HCl and NO2 are very low. Clear increases in the overburdens of HF and HNO3 were observed during the course of September in the vortex core. HCl and NO2 exhibited smaller, less significant increases. The overburdens of the tropospheric source gases, N2O, CH4, CF2Cl2, and H2O were observed to much smaller over Antarctica than at mid-latitudes. This, together with the fact that HF over Antarctica was more that double its mid-latitude value, suggests that downwelling has occurred.

  7. Flight service evaluation of an advanced composite empennage component on commercial transport aircraft. Phase 1: Engineering development

    NASA Technical Reports Server (NTRS)

    Ary, A.; Axtell, C.; Fogg, L.; Jackson, A.; James, A. M.; Mosesian, B.; Vanderwier, J.; Vanhamersveld, J.

    1976-01-01

    The empennage component selected for this program is the vertical fin box of the L-1011 aircraft. The box structure extends from the fuselage production joint to the tip rib and includes the front and rear spars. Various design options were evaluated to arrive at a configuration which would offer the highest potential for satisfying program objectives. The preferred configuration selected consists of a hat-stiffened cover with molded integrally stiffened spars, aluminum trussed composite ribs, and composite miniwich web ribs with integrally molded caps. Material screening tests were performed to select an advanced composite material system for the Advanced Composite Vertical Fin (ACFV) that would meet the program requirements from the standpoint of quality, reproducibility, and cost. Preliminary weight and cost analysis were made, targets established, and tracking plans developed. These include FAA certification, ancillary test program, quality control, and structural integrity control plans.

  8. The effects of aircraft fuel and fluids on the strength properties of Resin Transfer Molded (RTM) composites

    NASA Technical Reports Server (NTRS)

    Falcone, Anthony; Dow, Marvin B.

    1993-01-01

    The resin transfer molding (RTM) process offers important advantages for cost-effective composites manufacturing, and consequently has become the subject of intense research and development efforts. Several new matrix resins have been formulated specifically for RTM applications in aircraft and aerospace vehicles. For successful use on aircraft, composite materials must withstand exposure to the fluids in common use. The present study was conducted to obtain comparative screening data on several state-ofthe-art RTM resins after environmental exposures were performed on RTM composite specimens. Four graphite/epoxy composites and one graphite/bismaleimide composite were tested; testing of two additional graphite epoxy composites is in progress. Zero-deg tension tests were conducted on specimens machined from eight-ply (+45-deg, -45-deg) laminates, and interlaminar shear tests were conducted on 32-ply 0-deg laminate specimens. In these tests, the various RTM resins demonstrated widely different strengths, with 3501-6 epoxy being the strongest. As expected, all of the matrix resins suffered severe strength degradation from exposure to methylene chloride (paint stripper). The 3501-6 epoxy composites exhibited about a 30 percent drop in tensile strength in hot, wet tests. The E905-L epoxy exhibited little loss of tensile strength (less than 8 percent) after exposure to water. The CET-2 and 862 epoxies as well as the bismaleimide exhibited reduced strengths at elevated temperature after exposure to oils and fuel. In terms of the percentage strength reductions, all of the RTM matrix resins compared favorably with 3501-6 epoxy.

  9. Advanced X-Ray Inspection of Reinforced Carbon Composite Materials on the Orbiter Leading Edge Structural Subsystem (LESS)

    NASA Technical Reports Server (NTRS)

    Hernandez, Jose M.; Berry, Robert F.; Osborn, Robin; Bueno, Clifford; Osterlitz, Mark; Mills, Richard; Morris, Philip; Phalen, Robert; McNab, Jim; Thibodeaux, Tahanie; Thompson, Kyle

    2004-01-01

    The post return-to-flight (RTF) inspection methodology for the Orbiter Leading Edge Structural Subsystem (LESS) is currently being defined. Numerous NDT modalities and techniques are being explored to perform the flight-to-flight inspections of the reinforced carbon/carbon (RCC) composite material for impact damage, general loss of mass in the bulk layers, or other anomalous conditions that would pose risk to safe return upon re-entry. It is possible to have an impact upon ascent that is not visually observable on the surface, yet causes internal damage. Radiographic testing may be a useful NDT technique for such occurrences. The authors have performed radiographic tests on full-sized mock samples of LESS hardware with embedded image quality phantoms. Digitized radiographic film, computed radiography and flat panel digital real-time radiography was acquired using a GE Eresco 200 x-ray tube, and Se-75 and Yb-169 radioisotopes.

  10. A preliminary design study of a laminar flow control wing of composite materials for long range transport aircraft

    NASA Technical Reports Server (NTRS)

    Swinford, G. R.

    1976-01-01

    The results of an aircraft wing design study are reported. The selected study airplane configuration is defined. The suction surface, ducting, and compressor systems are described. Techniques of manufacturing suction surfaces are identified and discussed. A wing box of graphite/epoxy composite is defined. Leading and trailing edge structures of composite construction are described. Control surfaces, engine installation, and landing gear are illustrated and discussed. The preliminary wing design is appraised from the standpoint of manufacturing, weight, operations, and durability. It is concluded that a practical laminar flow control (LFC) wing of composite material can be built, and that such a wing will be lighter than an equivalent metal wing. As a result, a program of suction surface evaluation and other studies of configuration, aerodynamics, structural design and manufacturing, and suction systems are recommended.

  11. The Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS) mission: design, execution, and first results

    NASA Astrophysics Data System (ADS)

    Jacob, D. J.; Crawford, J. H.; Maring, H.; Clarke, A. D.; Dibb, J. E.; Emmons, L. K.; Ferrare, R. A.; Hostetler, C. A.; Russell, P. B.; Singh, H. B.; Thompson, A. M.; Shaw, G. E.; McCauley, E.; Pederson, J. R.; Fisher, J. A.

    2010-06-01

    The NASA Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS) mission was conducted in two 3-week deployments based in Alaska (April 2008) and western Canada (June-July 2008). Its goal was to better understand the factors driving current changes in Arctic atmospheric composition and climate, including (1) influx of mid-latitude pollution, (2) boreal forest fires, (3) aerosol radiative forcing, and (4) chemical processes. The June-July deployment was preceded by one week of flights over California (ARCTAS-CARB) focused on (1) improving state emission inventories for greenhouse gases and aerosols, (2) providing observations to test and improve models of ozone and aerosol pollution. ARCTAS involved three aircraft: a DC-8 with a detailed chemical payload, a P-3 with an extensive aerosol and radiometric payload, and a B-200 with aerosol remote sensing instrumentation. The aircraft data augmented satellite observations of Arctic atmospheric composition, in particular from the NASA A-Train. The spring phase (ARCTAS-A) revealed pervasive Asian pollution throughout the Arctic as well as significant European pollution below 2 km. Unusually large Siberian fires in April 2008 caused high concentrations of carbonaceous aerosols and also affected ozone. Satellite observations of BrO column hotspots were found not to be related to Arctic boundary layer events but instead to tropopause depressions, suggesting the presence of elevated inorganic bromine (5-10 pptv) in the lower stratosphere. Fresh fire plumes from Canada and California sampled during the summer phase (ARCTAS-B) indicated low NOx emission factors from the fires, rapid conversion of NOx to PAN, no significant secondary aerosol production, and no significant ozone enhancements except when mixed with urban pollution.

  12. Structural Integrity Evaluation of the Lear Fan 2100 Aircraft

    NASA Technical Reports Server (NTRS)

    Kan, H. P.; Dyer, T. A.

    1996-01-01

    An in-situ nondestructive inspection was conducted to detect manufacturing and assembly induced defects in the upper two wing surfaces (skin s) and upper fuselage skin of the Lear Fan 2100 aircraft E009. The effects of the defects, detected during the inspection, on the integrity of the structure was analytically evaluated. A systematic evaluation was also conducted to determine the damage tolerance capability of the upper wing skin against impact threats and assembly induced damage. The upper wing skin was divided into small regions for damage tolerance evaluations. Structural reliability, margin of safety, allowable strains, and allowable damage size were computed. The results indicated that the impact damage threat imposed on composite military aircraft structures is too severe for the Lear Fan 2100 upper wing skin. However, the structural integrity is not significantly degraded by the assembly induced damage for properly assembled structures, such as the E009 aircraft.

  13. Numerical simulation of two-dimensional heat transfer in composite bodies with application to de-icing of aircraft components. Ph.D. Thesis. Final Report

    NASA Technical Reports Server (NTRS)

    Chao, D. F. K.

    1983-01-01

    Transient, numerical simulations of the de-icing of composite aircraft components by electrothermal heating were performed for a two dimensional rectangular geometry. The implicit Crank-Nicolson formulation was used to insure stability of the finite-difference heat conduction equations and the phase change in the ice layer was simulated using the Enthalpy method. The Gauss-Seidel point iterative method was used to solve the system of difference equations. Numerical solutions illustrating de-icer performance for various composite aircraft structures and environmental conditions are presented. Comparisons are made with previous studies. The simulation can also be used to solve a variety of other heat conduction problems involving composite bodies.

  14. Transition from glass to graphite in manufacture of composite aircraft structure

    NASA Technical Reports Server (NTRS)

    Buffum, H. E.; Thompson, V. S.

    1978-01-01

    The transition from fiberglass reinforced plastic composites to graphite reinforced plastic composites is described. Structural fiberglass design and manufacturing background are summarized. How this experience provides a technology base for moving into graphite composite secondary structure and then to composite primary structure is considered. The technical requirements that must be fulfilled in the transition from glass to graphite composite structure are also included.

  15. Full-scale testing, production and cost analysis data for the advanced composite stabilizer for Boeing 737 aircraft. Volume 1: Technical summary

    NASA Technical Reports Server (NTRS)

    Aniversario, R. B.; Harvey, S. T.; Mccarty, J. E.; Parsons, J. T.; Peterson, D. C.; Pritchett, L. D.; Wilson, D. R.; Wogulis, E. R.

    1983-01-01

    The full scale ground test, ground vibration test, and flight tests conducted to demonstrate a composite structure stabilizer for the Boeing 737 aircraft and obtain FAA certification are described. Detail tools, assembly tools, and overall production are discussed. Cost analyses aspects covered include production costs, composite material usage factors, and cost comparisons.

  16. Preliminary design study of advanced composite blade and hub and nonmechanical control system for the tilt-rotor aircraft. Volume 2: Project planning data

    NASA Technical Reports Server (NTRS)

    1980-01-01

    Project planning data for a rotor and control system procurement and testing program for modifications to the XV-15 tilt-rotor research demonstrator aircraft is presented. The design, fabrication, and installation of advanced composite blades compatible with the existing hub, an advanced composite hub, and a nonmechanical control system are required.

  17. Preliminary design study of advanced composite blade and hub and nonmechanical control system for the tilt-rotor aircraft. Volume 1: Engineering studies

    NASA Technical Reports Server (NTRS)

    Alexander, H. R.; Smith, K. E.; Mcveigh, M. A.; Dixon, P. G.; Mcmanus, B. L.

    1979-01-01

    Composite structures technology is applied in a preliminary design study of advanced technology blades and hubs for the XV-15 tilt rotor research demonstrator aircraft. Significant improvements in XV-15 hover and cruise performance are available using blades designed for compatibility with the existing aircraft, i.e., blade installation would not require modification of the airframe, hub or upper controls. Provision of a low risk nonmechanical control system was also studied, and a development specification is given.

  18. Analytical and experimental investigation of aircraft metal structures reinforced with filamentary composites. Phase 1: Concept development and feasibility

    NASA Technical Reports Server (NTRS)

    Oken, S.; June, R. R.

    1971-01-01

    The analytical and experimental investigations are described in the first phase of a program to establish the feasibility of reinforcing metal aircraft structures with advanced filamentary composites. The interactions resulting from combining the two types of materials into single assemblies as well as their ability to function structurally were studied. The combinations studied were boron-epoxy reinforced aluminum, boron-epoxy reinforced titanium, and boron-polyimide reinforced titanium. The concepts used unidirectional composites as reinforcement in the primary loading direction and metal for carrying the transverse loads as well as its portion of the primary load. The program established that several realistic concepts could be fabricated, that these concepts could perform to a level that would result in significant weight savings, and that there are means for predicting their capability within a reasonable degree of accuracy. This program also encountered problems related to the application of polyimide systems that resulted in their relatively poor and variable performance.

  19. In-Flight Lightning Measurements and Reconstruction on a Metallic and Composite Aircraft

    NASA Astrophysics Data System (ADS)

    Boiddin, J.-F.; Flourens, F.; De Boer, A.; Bardet, M.; Herve, A.; Perez, G.; Riccio, L.

    2012-05-01

    Based on the success of the In-flight Lightning Strike Damage Assessment System (ILDAS) project launched within the scope of the Sixth Framework Programme of the European Commission and completed in July 2009, the results described in this paper form part of the ILDAS2 project initiated by Airbus Operations SAS in partnership with EADS IW and NLR. The principle aim of ILDAS2 project is to develop a system installed aboard an aircraft in order to determine the level, the current waveform and the attachments points of a lightning strike during an aircraft flight. The expectations linked to ILDAS2, the functional architecture of the system, the status and the projection of this development will be presented.

  20. Flight service evaluation of Kevlar-49 epoxy composite panels in wide-bodied commercial transport aircraft

    NASA Technical Reports Server (NTRS)

    Stone, R. H.

    1980-01-01

    Kevlar-49 fairing panels, installed as flight service components on three L-1011s, were inspected after 6 years' service. The Kevlar-49 components were found to be performing satisfactorily in service with no major problems, or any condition requiring corrective action. The only defects noted were minor impact damage, and a minor degree of fastener hole fraying and elongation. These are for the most part comparable to damage noted on fiberglass fairings.

  1. Preliminary weight and cost estimates for transport aircraft composite structural design concepts

    NASA Technical Reports Server (NTRS)

    1973-01-01

    Preliminary weight and cost estimates have been prepared for design concepts utilized for a transonic long range transport airframe with extensive applications of advanced composite materials. The design concepts, manufacturing approach, and anticipated details of manufacturing cost reflected in the composite airframe are substantially different from those found in conventional metal structure and offer further evidence of the advantages of advanced composite materials.

  2. Structural Diagnostics of CFRP Composite Aircraft Components by Ultrasonic Guided Waves and Built-In Piezoelectric Transducers

    SciTech Connect

    Howard M. Matt

    2007-02-15

    To monitor in-flight damage and reduce life-cycle costs associated with CFRP composite aircraft, an autonomous built-in structural health monitoring (SHM) system is preferred over conventional maintenance routines and schedules. This thesis investigates the use of ultrasonic guided waves and piezoelectric transducers for the identification and localization of damage/defects occurring within critical components of CFRP composite aircraft wings, mainly the wing skin-to-spar joints. The guided wave approach for structural diagnostics was demonstrated by the dual application of active and passive monitoring techniques. For active interrogation, the guided wave propagation problem was initially studied numerically by a semi-analytical finite element method, which accounts for viscoelastic damping, in order to identify ideal mode-frequency combinations sensitive to damage occurring within CFRP bonded joints. Active guided wave tests across three representative wing skin-to-spar joints at ambient temperature were then conducted using attached Macro Fiber Composite (MFC) transducers. Results from these experiments demonstrate the importance of intelligent feature extraction for improving the sensitivity to damage. To address the widely neglected effects of temperature on guided wave base damage identification, analytical and experimental analyses were performed to characterize the influence of temperature on guided wave signal features. In addition, statistically-robust detection of simulated damage in a CFRP bonded joint was successfully achieved under changing temperature conditions through a dimensionally-low, multivariate statistical outlier analysis. The response of piezoceramic patches and MFC transducers to ultrasonic Rayleigh and Lamb wave fields was analytically derived and experimentally validated. This theory is useful for designing sensors which possess optimal sensitivity toward a given mode-frequency combination or for predicting the frequency dependent

  3. Study on Design of High Efficiency and Light Weight Composite Propeller Blade for a Regional Turboprop Aircraft

    NASA Astrophysics Data System (ADS)

    Kong, Changduk; Lee, Kyungsun

    2013-03-01

    In this study, aerodynamic and structural design of the composite propeller blade for a regional turboprop aircraft is performed. The thin and wide chord propeller blade of high speed turboprop aircraft should have proper strength and stiffness to carry various kinds of loads such as high aerodynamic bending and twisting moments and centrifugal forces. Therefore the skin-spar-foam sandwich structure using high strength and stiffness carbon/epoxy composite materials is used to improve the lightness. A specific design procedure is proposed in this work as follows; firstly the aerodynamic configuration design, which is acceptable for the design requirements, is carried out using the in-house code developed by authors, secondly the structure design loads are determined through the aerodynamic load case analysis, thirdly the spar flange and the skin are preliminarily sized by consideration of major bending moments and shear forces using both the netting rule and the rule of mixture, and finally, the stress analysis is performed to confirm the structural safety and stability using finite element analysis commercial code, MSC. NASTRAN/PATRAN. Furthermore the additional analysis is performed to confirm the structural safety due to bird strike impact on the blade during flight operation using a commercial code, ANSYS. To realize the proposed propeller design, the prototype blades are manufactured by the following procedure; the carbon/epoxy composite fabric prepregs are laid up for skin and spar on a mold using the hand lay-up method and consolidated with a proper temperature and vacuum in the oven. To finalize the structural design, the full-scale static structural test is performed under the simulated aerodynamic loads using 3 point loading method. From the experimental results, it is found that the designed blade has a good structural integrity, and the measured results agree well with the analytical results as well.

  4. Structural diagnostics of CFRP composite aircraft components by ultrasonic guided waves and built-in piezoelectric transducers

    NASA Astrophysics Data System (ADS)

    Matt, Howard M.

    2006-07-01

    To monitor in-flight damage and reduce life-cycle costs associated with CFRP composite aircraft, an autonomous built-in structural health monitoring (SHM) system is preferred over conventional maintenance routines and schedules. This thesis investigates the use of ultrasonic guided waves and piezoelectric transducers for the identification and localization of damage/defects occurring within critical components of CFRP composite aircraft wings, mainly the wing skin-to-spar joints. The guided wave approach for structural diagnostics was demonstrated by the dual application of active and passive monitoring techniques. For active interrogation, the guided wave propagation problem was initially studied numerically by a semi-analytical finite element method, which accounts for viscoelastic damping, in order to identify ideal mode-frequency combinations sensitive to damage occurring within CFRP bonded joints. Active guided wave tests across three representative wing skin-to-spar joints at ambient temperature were then conducted using attached Macro Fiber Composite (MFC) transducers. Results from these experiments demonstrate the importance of intelligent feature extraction for improving sensitivity to damage. To address the widely neglected effects of temperature on guided wave base damage identification, analytical and experimental analyses were performed to characterize the influence of temperature on guided wave signal features. In addition, statistically-robust detection of simulated damage in a CFRP bonded joint was successfully achieved under changing temperature conditions through a dimensionally-low, multivariate statistical outlier analysis. The response of piezoceramic patches and MFC transducers to ultrasonic Rayleigh and Lamb wave fields was analytically derived and experimentally validated. This theory is useful for designing sensors which possess optimal sensitivity toward a given mode-frequency combination or for predicting the frequency dependent

  5. Vibrational behavior of adaptive aircraft wing structures modelled as composite thin-walled beams

    NASA Technical Reports Server (NTRS)

    Song, O.; Librescu, L.; Rogers, C. A.

    1992-01-01

    The vibrational behavior of cantilevered aircraft wings modeled as thin-walled beams and incorporating piezoelectric effects is studied. Based on the converse piezoelectric effect, the system of piezoelectric actuators conveniently located on the wing yield the control of its associated vertical and lateral bending eigenfrequencies. The possibility revealed by this study enabling one to increase adaptively the eigenfrequencies of thin-walled cantilevered beams could play a significant role in the control of the dynamic response and flutter of wing and rotor blade structures.

  6. Aircraft observations of Venus' near-infrared reflection spectrum - Implications for cloud composition

    NASA Technical Reports Server (NTRS)

    Pollack, J. B.; Erickson, E. F.; Witteborn, F. C.; Chackerian, C., Jr.; Summers, A. L.; Van Camp, W.; Baldwin, B. J.; Augason, G. C.; Caroff, L. J.

    1974-01-01

    A comparison of aircraft-based measurement data on Venus' near-infrared (1.2- to 4.1-micron) reflection spectrum with computer generated spectra of a number of cloud candidates shows a 75-% or more concentrated water solution of sulfuric acid to give the only acceptable match to the profile of Venus' strong 3-micron absorption feature. However, the measurement data obtained also show a modest decline in reflectivity from 2.3-micron to 1.2-micron wavelength, which is inconsistent with the flat spectrum of sulfuric acid in this spectral region. It is hypothesized that this decline is due to impurities in the sulfuric acid droplets.

  7. Testing and Analysis of a Composite Non-Cylindrical Aircraft Fuselage Structure. Part 1; Ultimate Design Loads

    NASA Technical Reports Server (NTRS)

    Przekop, Adam; Jegley, Dawn C.; Lovejoy, Andrew E.; Rouse, Marshall; Wu, Hsi-Yung T.

    2016-01-01

    The Environmentally Responsible Aviation Project aimed to develop aircraft technologies enabling significant fuel burn and community noise reductions. Small incremental changes to the conventional metallic alloy-based 'tube and wing' configuration were not sufficient to achieve the desired metrics. One airframe concept identified by the project as having the potential to dramatically improve aircraft performance was a composite-based hybrid wing body configuration. Such a concept, however, presented inherent challenges stemming from, among other factors, the necessity to transfer wing loads through the entire center fuselage section which accommodates a pressurized cabin confined by flat or nearly flat panels. This paper discusses finite element analysis and testing of a large-scale hybrid wing body center section structure developed and constructed to demonstrate that the Pultruded Rod Stitched Efficient Unitized Structure concept can meet these challenging demands of the next generation airframes. Part I of the paper considers the five most critical load conditions, which are internal pressure only and positive and negative g-loads with and without internal pressure. Analysis results are compared with measurements acquired during testing. Performance of the test article is found to be closely aligned with predictions and, consequently, able to support the hybrid wing body design loads in pristine and barely visible impact damage conditions.

  8. Aircraft landing gear systems

    NASA Technical Reports Server (NTRS)

    Tanner, John A. (Editor)

    1990-01-01

    Topics presented include the laboratory simulation of landing gear pitch-plane dynamics, a summary of recent aircraft/ground vehicle friction measurement tests, some recent aircraft tire thermal studies, and an evaluation of critical speeds in high-speed aircraft. Also presented are a review of NASA antiskid braking research, titanium matrix composite landing gear development, the current methods and perspective of aircraft flotation analysis, the flow rate and trajectory of water spray produced by an aircraft tire, and spin-up studies of the Space Shuttle Orbiter main gear tire.

  9. Evaluation of low-cost aluminum composites for aircraft engine structural applications

    NASA Technical Reports Server (NTRS)

    Mcdanels, D. L.; Signorelli, R. A.

    1983-01-01

    Panels of discontinuous SiC composites, with several aluminum matrices, were fabricated and evaluated. Modulus, yield strength and tensile strength results indicated that the properties of composites containing SiC whisker, nodule or particulate reinforcements were similar. The modulus of the composites was controlled by the volume percentage of the SiC reinforcement content, while the strength and ductility were controlled by both the reinforcement content and the matrix alloy. The feasibility of fabricating structural shapes by both wire performs and direct casting was demonstrated for Al2O3/Al composites. The feasibility of fabricating high performance composites into structural shapes by low pressure hot molding was demonstrated for B4C-coated B/Al composites.

  10. Design, Fabrication, and Testing of Composite Energy-Absorbing Keel Beams for General Aviation Type Aircraft

    NASA Technical Reports Server (NTRS)

    Kellas, Sotiris; Knight, Norman F., Jr.

    2002-01-01

    A lightweight energy-absorbing keel-beam concept was developed and retrofitted in a general aviation type aircraft to improve crashworthiness performance. The energy-absorbing beam consisted of a foam-filled cellular structure with glass fiber and hybrid glass/kevlar cell walls. Design, analysis, fabrication and testing of the keel beams prior to installation and subsequent full-scale crash testing of the aircraft are described. Factors such as material and fabrication constraints, damage tolerance, crush stress/strain response, seat-rail loading, and post crush integrity, which influenced the course of the design process are also presented. A theory similar to the one often used for ductile metal box structures was employed with appropriate modifications to estimate the sustained crush loads for the beams. This, analytical tool, coupled with dynamic finite element simulation using MSC.Dytran were the prime design and analysis tools. The validity of the theory as a reliable design tool was examined against test data from static crush tests of beam sections while the overall performance of the energy-absorbing subfloor was assessed through dynamic testing of 24 in long subfloor assemblies.

  11. Small- and medium-scale effects of high-flying aircraft exhausts on the atmospheric composition

    NASA Astrophysics Data System (ADS)

    Karol, I. L.; Ozolin, Y. E.

    1994-10-01

    Following numerous model studies of the global impacts of sub- and supersonic aircraft on the atmosphere, this paper assesses the separate aircraft engine exhaust effects of the 45°N cruise flight and at the 10- and 18-km levels of the July atmosphere. A box diffusion photochemical model in the cross-section plane of the flight trajectory is used to compute the effects of gas-phase and heterogeneous reactions on the condensation trail particles in the troposphere, and on the sulphate aerosols in the stratosphere. The enhanced horizontal dispersion of the exhaust plume is considered in the model. A significant but short term depletion of ozone is predicted, which is 99% restored in about 1 h in the wide plume with enhanced horizontal dispersion, but requires more than 24 h in the narrow plume without it. The oxidation rate of NO and NO2 into the HNO3 depends on the OH content in the exhausts and varies in all the cases. The heterogeneous photochemistry has only a small influence on the initial evolution of N2O5 and HO2 in the plume.

  12. Advanced composites structural concepts and materials technologies for primary aircraft structures. Structural response and failure analysis: ISPAN modules users manual

    NASA Technical Reports Server (NTRS)

    Hairr, John W.; Huang, Jui-Ten; Ingram, J. Edward; Shah, Bharat M.

    1992-01-01

    The ISPAN Program (Interactive Stiffened Panel Analysis) is an interactive design tool that is intended to provide a means of performing simple and self contained preliminary analysis of aircraft primary structures made of composite materials. The program combines a series of modules with the finite element code DIAL as its backbone. Four ISPAN Modules were developed and are documented. These include: (1) flat stiffened panel; (2) curved stiffened panel; (3) flat tubular panel; and (4) curved geodesic panel. Users are instructed to input geometric and material properties, load information and types of analysis (linear, bifurcation buckling, or post-buckling) interactively. The program utilizing this information will generate finite element mesh and perform analysis. The output in the form of summary tables of stress or margins of safety, contour plots of loads or stress, and deflected shape plots may be generalized and used to evaluate specific design.

  13. A domain-specific design architecture for composite material design and aircraft part redesign

    NASA Technical Reports Server (NTRS)

    Punch, W. F., III; Keller, K. J.; Bond, W.; Sticklen, J.

    1992-01-01

    Advanced composites have been targeted as a 'leapfrog' technology that would provide a unique global competitive position for U.S. industry. Composites are unique in the requirements for an integrated approach to designing, manufacturing, and marketing of products developed utilizing the new materials of construction. Numerous studies extending across the entire economic spectrum of the United States from aerospace to military to durable goods have identified composites as a 'key' technology. In general there have been two approaches to composite construction: build models of a given composite materials, then determine characteristics of the material via numerical simulation and empirical testing; and experience-directed construction of fabrication plans for building composites with given properties. The first route sets a goal to capture basic understanding of a device (the composite) by use of a rigorous mathematical model; the second attempts to capture the expertise about the process of fabricating a composite (to date) at a surface level typically expressed in a rule based system. From an AI perspective, these two research lines are attacking distinctly different problems, and both tracks have current limitations. The mathematical modeling approach has yielded a wealth of data but a large number of simplifying assumptions are needed to make numerical simulation tractable. Likewise, although surface level expertise about how to build a particular composite may yield important results, recent trends in the KBS area are towards augmenting surface level problem solving with deeper level knowledge. Many of the relative advantages of composites, e.g., the strength:weight ratio, is most prominent when the entire component is designed as a unitary piece. The bottleneck in undertaking such unitary design lies in the difficulty of the re-design task. Designing the fabrication protocols for a complex-shaped, thick section composite are currently very difficult. It is in

  14. Non-Contact Ultrasound Based Guided Lamb Waves for Composite Structure Inspection: Some Interesting Observations

    NASA Astrophysics Data System (ADS)

    Karthikeyan, P.; Ramdas, C.; Bhardwaj, Mahesh C.; Balasubramaniam, Krishnan

    2009-03-01

    Quality assurance of the composite products becomes important to avoid defects during processing since they are used for critical applications. Non- Contact Ultrasound (NCU) technique using the A0 Lamb modes is explored here with applications in the detection, imaging, and sizing of defects in both honeycomb and more importantly composite laminates. A Finite Element Model was employed to understand the interactions of the Lamb modes with defects. Mode conversions at the two ends of a delamination and the time of flight differences between these were employed for the determination of the size of the delaminations in composite laminates. This method may allow for the two dimensional sizing of the delaminations in composite laminates using a single line-scan using the Lamb modes.

  15. Developing Large-Scale Bayesian Networks by Composition: Fault Diagnosis of Electrical Power Systems in Aircraft and Spacecraft

    NASA Technical Reports Server (NTRS)

    Mengshoel, Ole Jakob; Poll, Scott; Kurtoglu, Tolga

    2009-01-01

    In this paper, we investigate the use of Bayesian networks to construct large-scale diagnostic systems. In particular, we consider the development of large-scale Bayesian networks by composition. This compositional approach reflects how (often redundant) subsystems are architected to form systems such as electrical power systems. We develop high-level specifications, Bayesian networks, clique trees, and arithmetic circuits representing 24 different electrical power systems. The largest among these 24 Bayesian networks contains over 1,000 random variables. Another BN represents the real-world electrical power system ADAPT, which is representative of electrical power systems deployed in aerospace vehicles. In addition to demonstrating the scalability of the compositional approach, we briefly report on experimental results from the diagnostic competition DXC, where the ProADAPT team, using techniques discussed here, obtained the highest scores in both Tier 1 (among 9 international competitors) and Tier 2 (among 6 international competitors) of the industrial track. While we consider diagnosis of power systems specifically, we believe this work is relevant to other system health management problems, in particular in dependable systems such as aircraft and spacecraft. (See CASI ID 20100021910 for supplemental data disk.)

  16. Characterization and manufacture of braided composites for large commercial aircraft structures

    NASA Technical Reports Server (NTRS)

    Fedro, Mark J.; Willden, Kurtis

    1992-01-01

    Braided composite materials has been recognized as a potential cost effective material form for fuselage structural elements. Consequently, there is a strong need for more knowledge in the design, manufacture, test, and analysis of textile structural composites. Advance braided composite technology is advanced towards applications to a large commercial transport fuselage. The mechanics are summarized of materials and manufacturing demonstration results which were obtained in order to acquire an understanding of how braided composites can be applied to a commercial fuselage. Textile composites consisting of 2-D, 2-D triaxial, and 3-D braid patterns with thermoplastic and two resin transfer molding resin systems were studied. The structural performance of braided composites was evaluated through an extensive mechanical test program. Analytical methods were also developed and applied to predict the following: internal fiber architecture; stiffness; fiber stresses; failure mechanisms; notch effects; and the history of failure of the braided composite specimens. The applicability of braided composites to a commercial transport fuselage was further assessed through a manufacturing demonstration.

  17. Characterization and manufacture of braided composites for large commercial aircraft structures

    NASA Technical Reports Server (NTRS)

    Fedro, Mark J.; Willden, Kurtis

    1992-01-01

    Braided composite materials, one of the advanced material forms which is under investigation in Boeing's ATCAS program, have been recognized as a potential cost-effective material form for fuselage structural elements. Consequently, there is a strong need for more knowledge in the design, manufacture, test, and analysis of textile structural composites. The overall objective of this work is to advance braided composite technology towards applications to a large commercial transport fuselage. This paper summarizes the mechanics of materials and manufacturing demonstration results which have been obtained in order to acquire an understanding of how braided composites can be applied to a commercial fuselage. Textile composites consisting of 1D, 2D triaxial, and 3D braid patterns with thermoplastic and two RTM resin systems were investigated. The structural performance of braided composites was evaluated through an extensive mechanical test program. Analytical methods were also developed and applied to predict the following: internal fiber architectures, stiffnesses, fiber stresses, failure mechanisms, notch effects, and the entire history of failure of the braided composites specimens. The applicability of braided composites to a commercial transport fuselage was further assessed through a manufacturing demonstration. Three foot fuselage circumferential hoop frames were manufactured to demonstrate the feasibility of consistently producing high quality braided/RTM composite primary structures. The manufacturing issues (tooling requirements, processing requirements, and process/quality control) addressed during the demonstration are summarized. The manufacturing demonstration in conjunction with the mechanical test results and developed analytical methods increased the confidence in the ATCAS approach to the design, manufacture, test, and analysis of braided composites.

  18. Concepts for improving the damage tolerance of composite compression panels. [aircraft structures

    NASA Technical Reports Server (NTRS)

    Rhodes, M. D.; Williams, J. G.

    1984-01-01

    The residual strength of specimens with damage and the sensitivity to damage while subjected to an applied inplane compression load were determined for flatplate specimens and blade-stiffened panels. The results suggest that matrix materials that fail by delamination have the lowest damage tolerance capability. Alternate matrix materials or laminates which are transversely reinforced suppress the delamination mode of failure and change the failure mode to transverse shear crippling which occurs at a higher strain value. Several damage-tolerant blade-stiffened panel design concepts are evaluated. Structural efficiency studies conducted show only small mass penalties may result from incorporating these damage-tolerant features in panel design. The implication of test results on the design of aircraft structures was examined with respect to FAR requirements.

  19. Impact of environmental constraints and aircraft technology on airline fleet composition

    NASA Astrophysics Data System (ADS)

    Moolchandani, Kushal A.

    This thesis models an airline's decisions about fleet evolution in order to maintain economic and regulatory viability. The aim is to analyze the fleet evolution under different scenarios of environmental policy and technology availability in order to suggest an optimal fleet under each case. An understanding of the effect of aircraft technologies, fleet size and age distribution, and operational procedures on airline performance may improve the quality of policies to achieve environmental goals. Additionally, the effect of decisions about fleet evolution on air travel is assessed as the change in market demand and profits of an abstracted, benevolent monopolist airline. Attention to the environmental impact of aviation has grown, and this has prompted several organizations such as ICAO (and, in response, NASA) to establish emissions reduction targets to reduce aviation's global climate impact. The introduction of new technology, change in operational procedures, etc. are some of the proposed means to achieve these targets. Of these, this thesis studies the efficacy of implementation of environmental policies in form of emissions constraints as a means to achieve these goals and assesses their impact on an airline's fleet evolution and technology use (along with resulting effects on air travel demand). All studies in this thesis are conducted using the Fleet-level Environmental Evaluation Tool (FLEET), a NASA sponsored simulation tool developed at Purdue University. This tool models airline operational decisions via a resource allocation problem and uses a system dynamics type approach to mimic airline economics, their decisions regarding retirement and acquisition of aircraft and evolution of market demand in response to the economic conditions. The development of an aircraft acquisition model for FLEET is a significant contribution of the author. Further, the author conducted a study of various environmental policies using FLEET. Studies introduce constraints on

  20. Bonded repair of composite aircraft structures: A review of scientific challenges and opportunities

    NASA Astrophysics Data System (ADS)

    Katnam, K. B.; Da Silva, L. F. M.; Young, T. M.

    2013-08-01

    Advanced composite materials have gained popularity in high-performance structural designs such as aerospace applications that require lightweight components with superior mechanical properties in order to perform in demanding service conditions as well as provide energy efficiency. However, one of the major challenges that the aerospace industry faces with advanced composites - because of their inherent complex damage behaviour - is structural repair. Composite materials are primarily damaged by mechanical loads and/or environmental conditions. If material damage is not extensive, structural repair is the only feasible solution as replacing the entire component is not cost-effective in many cases. Bonded composite repairs (e.g. scarf patches) are generally preferred as they provide enhanced stress transfer mechanisms, joint efficiencies and aerodynamic performance. With an increased usage of advanced composites in primary and secondary aerospace structural components, it is thus essential to have robust, reliable and repeatable structural bonded repair procedures to restore damaged composite components. But structural bonded repairs, especially with primary structures, pose several scientific challenges with the current existing repair technologies. In this regard, the area of structural bonded repair of composites is broadly reviewed - starting from damage assessment to automation - to identify current scientific challenges and future opportunities.

  1. Impact Testing and Analysis of Composites for Aircraft Engine Fan Cases

    NASA Technical Reports Server (NTRS)

    Roberts, Gary D.; Revilock, Duane M.; Binienda, Wieslaw K.; Nie, Walter Z.; Mackenzie, S. Ben; Todd, Kevin B.

    2002-01-01

    The fan case in a jet engine is a heavy structure because of its size and because of the requirement that it contain a blade released during engine operation. Composite materials offer the potential for reducing the weight of the case. Efficient design, test, and analysis methods are needed to efficiently evaluate the large number of potential composite materials and design concepts. The type of damage expected in a composite case under blade-out conditions was evaluated using a subscale test in which a glass/epoxy composite half-ring target was impacted with a wedge-shaped titanium projectile. Fiber shearing occurred near points of contact between the projectile and target. Delamination and tearing occurred on a larger scale. These damage modes were reproduced in a simpler test in which flat glass/epoxy composites were impacted with a blunt cylindrical projectile. A surface layer of ceramic eliminated fiber shear fracture but did not reduce delamination. Tests on 3D woven carbon/epoxy composites indicated that transverse reinforcement is effective in reducing delamination. A 91 cm (36 in.) diameter full-ring sub-component was proposed for larger scale testing of these and other composite concepts. Explicit, transient, finite element analyses indicated that a full-ring test is needed to simulate complete impact dynamics, but simpler tests using smaller ring sections are adequate when evaluation of initial impact damage is the primary concern.

  2. Advanced composite aileron for L-1011 transport aircraft: Design and analysis

    NASA Technical Reports Server (NTRS)

    Griffin, C. F.; Fogg, L. D.; Dunning, E. G.

    1981-01-01

    Detail design of the composite aileron has been completed. The aileron design is a multi-rib configuration with single piece upper and lower covers mechanically fastened to the substructure. Covers, front, spar and ribs are fabricated with graphite/epoxy tape or fabric composite material. The design has a weight savings of 23 percent compared to the aluminum aileron. The composite aileron has 50 percent fewer fasteners and parts than the metal aileron and is predicted to be cost competitive. Structural integrity of the composite aileron was verified by structural analysis and an extensive test program. Static, failsafe, and vibration analyses have been conducted on the composite aileron using finite element models and specialized computer programs for composite material laminates. The fundamental behavior of the composite materials used in the aileron was determined by coupon tests for a variety of environmental conditions. Critical details of the design were interrogated by static and fatigue tests on full-scale subcomponents and subassemblies of the aileron.

  3. Crack detection on HU-25 Guardian aircraft

    SciTech Connect

    Moore, D.G.; Jones, C.R.; Mihelic, J.E.; Dassler, E.; Walizer, J.

    1996-10-01

    An ultrasonic inspection method was developed at FAA`s Airworthiness Assurance NDI Validation Center (AANC) to easily and rapidly detect hidden fatigue cracks in the copilot vertical windshield post on USCG (Coast Guard) HU-25 `Guardian` aircraft. The inspection procedure locates hidden cracks as small as 3.2 mm emanating from internal fastener holes and determines their length. A test procedure was developed and a baseline assessment of the USCG fleet conducted. Inspection results on 41 aircraft revealed good correlation with results made during subsequent structural disassembly and visual inspection of selected aircraft.

  4. Fiber Bragg grating sensing in smart composite patch repairs for aging aircraft

    NASA Astrophysics Data System (ADS)

    Botsev, Y.; Gorbatov, Nahum; Tur, Moshe; Ben-Simon, U.; Kressel, I.; Green, A. K.; Ghilai, G.; Gali, S.

    2004-06-01

    A Fiber-Bragg-Grating based, advanced co-cured smart composite patch for the repair of metallic structures is proposed and demonstrated. Advantages include real time cure monitoring and long-term in-service structural integrity evaluation.

  5. A multi-inspection non-destructive testing method for quality evaluation of composite riveted structure

    NASA Astrophysics Data System (ADS)

    Wang, Weihan; He, Jingjing; Yang, Jingsong; Liu, Shengwang; Zhang, Weifang

    2015-03-01

    Carbon fiber composites have excellent mechanical properties, which are widely used in aerospace industry. However, 60% to 80% damages in composite occur in riveted structures. This research focuses on the quality evaluation of three major riveted structures used in mechanical connection: pressure riveted connection, hammer riveted connection and pull riveted connection. The non-destructive testing results show that the pull riveting technology introduces minimal damage to the composite, but the hammer riveted structure can be seriously damaged by the riveting technology. The pull riveted structure is an interference fit, which makes the composite plate firmly fixed. However, the fix is weak in the pressure riveted structure and the hammer riveted structure, due to the small gap between the rivets and plate. The results show that the pull riveted structure has a higher tensile strength compared with the pressure riveted structure and hammer riveted structure. The hammer riveted structure has a large dispersion in mechanical properties caused by the impact loading used in the hammer riveting technology.

  6. Behavior of composite/metal aircraft structural elements and components under crash type loads: What are they telling us

    NASA Technical Reports Server (NTRS)

    Carden, Huey D.; Boitnott, Richard L.; Fasanella, Edwin L.

    1990-01-01

    Failure behavior results are presented from crash dynamics research using concepts of aircraft elements and substructure not necessarily designed or optimized for energy absorption or crash loading considerations. To achieve desired new designs which incorporate improved energy absorption capabilities often requires an understanding of how more conventional designs behave under crash loadings. Experimental and analytical data are presented which indicate some general trends in the failure behavior of a class of composite structures which include individual fuselage frames, skeleton subfloors with stringers and floor beams but without skin covering, and subfloors with skin added to the frame-stringer arrangement. Although the behavior is complex, a strong similarity in the static and dynamic failure behavior among these structures is illustrated through photographs of the experimental results and through analytical data of generic composite structural models. It is believed that the similarity in behavior is giving the designer and dynamists much information about what to expect in the crash behavior of these structures and can guide designs for improving the energy absorption and crash behavior of such structures.

  7. Characterization of Delaminations and Transverse Matrix Cracks in Composite Laminates Using Multiple-Angle Ultrasonic Inspection

    NASA Technical Reports Server (NTRS)

    Johnston, Patrick H.; Appleget, Chelsea D.; Odarczenko, Michael T.

    2012-01-01

    Delaminations and transverse matrix cracks often appear concurrently in composite laminates. Normal-incidence ultrasound is excellent at detecting delaminations, but is not optimum for matrix cracks. Non-normal incidence, or polar backscattering, has been shown to optimally detect matrix cracks oriented perpendicular to the ultrasonic plane of incidence. In this work, a series of six composite laminates containing slots were loaded in tension to achieve various levels of delamination and ply cracking. Ultrasonic backscattering was measured over a range of incident polar and azimuthal angles, in order to characterize the relative degree of damage of the two types. Sweptpolar- angle measurements were taken with a curved phased array, as a step toward an array-based approach to simultaneous measurement of combined flaws.

  8. Infrared aircraft measurements of stratospheric composition over Antarctica during September 1987

    SciTech Connect

    Toon, G.C.; Farmer, C.B.; Lowes, L.L.; Schaper, P.W.; Blavier, J.F.; Norton, R.H. )

    1989-11-30

    The Jet Propulsion Laboratory Mark IV interferometer recorded high-resolution, infrared solar spectra from the NASA DC-8 aircraft during flights over Antarctica in September 1987. The atmospheric absorption features in these spectra have been analyzed to determine the burdens of O{sub 3}, NO, NO{sub 2}, HNO{sub 3}, ClNO{sub 3}, HCl, HF, CO{sub 2}, CH{sub 4}, N{sub 2}O, HCN, CO, H{sub 2}O, CFCl{sub 3}, and CF{sub 2}Cl{sub 2}. The results show a collar of high HNO{sub 3} and ClNO{sub 3} surrounding a core in which the burdens of these and of HCl and NO{sub 2} are very low. Clear increases in the burdens of HF and HNO{sub 3} were observed during the course of September in the Vortex core. HCl and NO{sub 2} exhibited smaller, less significant increases. The burdens of the tropospheric source gases, N{sub 2}O, CH{sub 4}, HCN, CFCl{sub 3}, CF{sub 2}Cl{sub 2}, CO, and H{sub 2}O, were observed to be much smaller over Antarctica than at mid-latitudes. This, together with the fact that HF over Antarctica was more than double its mid-latitude value, suggests that downwelling had occurred.

  9. Thermography inspection for detection and tracking of composite cylinder damage during load testing

    SciTech Connect

    Zalameda, J. N.; Winfree, W. P.; Johnston, P. H.; Seebo, J. P.

    2011-06-23

    Two thermography techniques, passive and active, are used to detect damage initiation and progression in a cyclically loaded composite cylinder. The passive thermography tracks damage progression in real time during cyclic loading. Active flash thermography, using a flash tube enclosed within the cylinder, images delaminations. A differential thermography processing technique eliminates normal material variations and improves sensitivity to and sizing of delaminations. The thermography results were compared to non-immersion ultrasonic results.

  10. Thermography Inspection for Detection and Tracking of Composite Cylinder Damage During Load Testing

    NASA Technical Reports Server (NTRS)

    Zalameda, J. N.; Winfree, W. P.; Seebo, J. P.; Johnston, P. H.

    2010-01-01

    Two thermography techniques, passive and active, are used to detect damage initiation and progression in a cyclically loaded composite cylinder. The passive thermography tracks damage progression in real time during cyclic loading. Active flash thermography, using a flash tube enclosed within the cylinder, images delaminations in a cylinder under different loads. A differential thermography processing technique eliminates normal material variations and improves sensitivity to and sizing of delaminations. The thermography results were compared to nonimmersion ultrasonic results.

  11. Impact resistance of fiber composite blades used in aircraft turbine engines

    NASA Technical Reports Server (NTRS)

    Friedrich, L. A.; Preston, J. L., Jr.

    1973-01-01

    Resistance of advanced fiber reinforced epoxy matrix composite materials to ballistic impact was investigated as a function of impacting projectile characteristics, and composite material properties. Ballistic impact damage due to normal impacts, was classified as transverse (stress wave delamination and splitting), penetrative, or structural (gross failure). Steel projectiles were found to be gelatin ice projectiles in causing penetrative damage leading to reduced tensile strength. Gelatin and ice projectiles caused either transverse or structural damage, depending upon projectile mass and velocity. Improved composite transverse tensile strength, use of dispersed ply lay-ups, and inclusion of PRD-49-1 or S-glass fibers correlated with improved resistance of composite materials to transverse damage. In non-normal impacts against simulated blade shapes, the normal velocity component of the impact was used to correlate damage results with normal impact results. Stiffening the leading edge of simulated blade specimens led to reduced ballistic damage, while addition of a metallic leading edge provided nearly complete protection against 0.64 cm diameter steel, and 1.27 cm diameter ice and gelatin projectiles, and partial protection against 2.54 cm diameter projectiles of ice and gelatin.

  12. X-ray imaging inspection of fiberglass reinforced by epoxy composite

    NASA Astrophysics Data System (ADS)

    Rique, A. M.; Machado, A. C.; Oliveira, D. F.; Lopes, R. T.; Lima, I.

    2015-04-01

    The goal of this work was to study the voids presented in bonded joints in order to minimize failures due to low adhesion of the joints in the industry field. One of the main parameters to be characterized is the porosity of the glue, since these pores are formed by several reasons in the moment of its adhesion, which are formed by composite of epoxy resin reinforced by fiberglass. For such purpose, it was used high energy X-ray microtomography and the results show its potential effective in recognizing and quantifying directly in 3D all the occlusions regions presented at glass fiber-epoxy adhesive joints.

  13. MUSIC imaging method for electromagnetic inspection of composite multi-layers

    NASA Astrophysics Data System (ADS)

    Rodeghiero, Giacomo; Ding, Ping-Ping; Zhong, Yu; Lambert, Marc; Lesselier, Dominique

    2015-03-01

    A first-order asymptotic formulation of the electric field scattered by a small inclusion (with respect to the wavelength in dielectric regime or to the skin depth in conductive regime) embedded in composite material is given. It is validated by comparison with results obtained using a Method of Moments (MoM). A non-iterative MUltiple SIgnal Classification (MUSIC) imaging method is utilized in the same configuration to locate the position of small defects. The effectiveness of the imaging algorithm is illustrated through some numerical examples.

  14. Novel Epoxy Particulate Composites for Mitigation of Insect Residue Adhesion on Future Aircraft Surfaces

    NASA Technical Reports Server (NTRS)

    Wohl, Christopher J.; Smith, Joseph G., Jr.; Gardner, John M.; Penner, Ronald K.; Connell, John W.; Siochi, Emilie J.

    2014-01-01

    Drag is reduced significantly for airflow over surfaces when laminar flow can be maintained over greater chord lengths, the distance from the leading edge of an airfoil.1 However, surface imperfections, such as chipped paint, scratches, and events that change topography on a microscopic scale can introduce airflow instabilities resulting in premature transition to turbulent flow.1 Although many of these surface imperfections can be avoided with proper maintenance, advanced materials, and advanced manufacturing practices, topographical surface anomalies arising during flight from insect impacts cannot be controlled and can influence laminar flow stability. Practical solutions to this operational challenge need to be developed for future aircraft to have full advantage of laminar flow designs that improve fuel efficiency.2 Researchers have investigated various methods to mitigate insect residue adhesion for decades.3 Although several techniques have demonstrated efficacy including mechanical scrapers, active liquid discharge systems, and sacrificial paper coatings, they have not been commercially implemented due to increased manufacturing and operational complexity, environmental impact, and weight penalties. Coatings offer a simple route for passive insect residue adhesion prevention without many of the challenges associated with maintenance of laminar flow.4 In our previous work, we determined that most commercially available materials were not effective at insect residue adhesion.5 We also identified improvements when both surface energy could be controlled by surface modifying agents and the topography could be altered through the use of micron-sized and nanometer-sized filler materials.6 In this work, these general principles were applied to an epoxy system to evaluate the behavior of the surface modifying agent, a fluorinated alkyl ether oligomer, on surface energy and insect residue adhesion properties.

  15. Composites applications - The future is now

    SciTech Connect

    Drozda, T.J.

    1989-01-01

    The present volume on the development status of advanced composites discusses resin-, ceramic- and metal-matrix composites, as well as tooling practices, testing and inspection methods, and novel applications. Attention is given to interface considerations in ceramic-matrix composites, applications of metal-matrix composites to military aircraft, advanced thermoplastic preforms, tooling for filament-winding processes, trapped-rubber molding methods, pultrusion for automotive applications, and composite-production tooling using CAD/CAM. Also discussed are expert systems for composites inspection and repair, acoustographic high-speed NDE for composites, the design and production of a composite landing gear-retracting beam, braided composite structures, and the uses of composites in orthopedics.

  16. Advanced composite rudders for DC-10 aircraft: Design, manufacturing, and ground tests

    NASA Technical Reports Server (NTRS)

    Lehman, G. M.; Purdy, D. M.; Cominsky, A.; Hawley, A. V.; Amason, M. P.; Kung, J. T.; Palmer, R. J.; Purves, N. B.; Marra, P. J.; Hancock, G. R.

    1976-01-01

    Design synthesis, tooling and process development, manufacturing, and ground testing of a graphite epoxy rudder for the DC-10 commercial transport are discussed. The composite structure was fabricated using a unique processing method in which the thermal expansion characteristics of rubber tooling mandrels were used to generate curing pressures during an oven cure cycle. The ground test program resulted in certification of the rudder for passenger-carrying flights. Results of the structural and environmental tests are interpreted and detailed development of the rubber tooling and manufacturing process is described. Processing, tooling, and manufacturing problems encountered during fabrication of four development rudders and ten flight-service rudders are discussed and the results of corrective actions are described. Non-recurring and recurring manufacturing labor man-hours are tabulated at the detailed operation level. A weight reduction of 13.58 kg (33 percent) was attained in the composite rudder.

  17. Separation of conductivity and distance measurements for eddy current nondestructive inspection of graphite composite materials

    NASA Astrophysics Data System (ADS)

    Dufour, Isabelle; Placko, Dominique

    1993-06-01

    This article deals with the study of a process based on the principle of eddy current sensors for the nondestructive evaluation of graphite composite plates. This research has been carried out in the Laboratoire d'Electricitd Signaux et Robotique by the team working on datacollecting sensors for robotics in collaboration with Aerospatiale. Eddy current sensors are characterized by their impedance, which varies when a conducting material is approached in their sensitive area. For a given sensor, the output signal depends directly on the electrical and geometrical properties of the object. In the case discussed here, the interesting data are the distance between the sensor and the object, and its local conductivity. In order to invert the relationships between the sensor signal and the properties of the material, an external parametrical model has been developed. A scanning of the surface with a sensor designed for good spatial resolution measurements gives two accurate maps of the useful data.

  18. Use Of Video In Microscopic And Ultrasonic Inspection

    NASA Technical Reports Server (NTRS)

    Generazio, Edward R.; Roth, Don J.

    1994-01-01

    Two combinations of video and image-data-processing techniques, tone-pulse encoding and precision acoustic imaging, yield grain- and pore-size distributions. Knowledge of such and of fiber orientation important because these characteristics directly related to tensile strength, hardness, fracture toughness, fracture stress, and resistance to impact. One of these combinations of techniques used in nondestructive evaluation of composite parts; both play important roles in development of lightweight composites for use at high temperatures in advanced engines and aircraft. Video system provides easy access to information on diffraction and refraction like that described in article, "Ultrasonic Inspection With Angular-Power-Spectrum Scanning" (LEW-15386).

  19. High Temperature Lightweight Self-Healing Ceramic Composites for Aircraft Engine Applications

    NASA Technical Reports Server (NTRS)

    Raj, Sai V.; Singh, Mrityunjay; Bhatt, Ramakrishna T.

    2014-01-01

    The present research effort was undertaken to develop a new generation of SiC fiber- reinforced engineered matrix composites (EMCs) with sufficient high temperature plasticity to reduce crack propagation and self-healing capabilities to fill surface-connected cracks to prevent the oxygen ingress to the fibers. A matrix engineered with these capabilities is expected to increase the load bearing capabilities of SiCSiC CMCs at high temperatures. Several matrix compositions were designed to match the coefficient of thermal expansion (CTE) of the SiC fibers using a rule of mixture (ROM) approach. The CTE values of these matrices were determined and it was demonstrated that they were generally in good agreement with that of monolithic SiC between room temperature and 1525 K. The parameters to hot press the powders were optimized, and specimens were fabricated for determining bend strength, CTE, oxidation and microstructural characteristics of the engineered matrices. The oxidation tests revealed that some of the matrices exhibited catastrophic oxidation, and therefore, these were eliminated from further consideration. Two promising compositions were down selected based on these results for further development. Four-point bend tests were conducted on these two promising matrices between room temperature and 1698 K. Although theses matrices were brittle and failed at low stresses at room temperature, they exhibited high temperature ductility and higher stresses at the higher temperatures. The effects of different additives on the self-healing capabilities of these matrices were investigated. The results of preliminary studies conducted to slurry and melt infiltration trials with CrSi2 are described.

  20. Elastomer toughened polyimide adhesives. [bonding metal and composite material structures for aircraft and spacecraft

    NASA Technical Reports Server (NTRS)

    St.clair, A. K.; St.clair, T. L. (Inventor)

    1985-01-01

    A rubber-toughened, addition-type polyimide composition is disclosed which has excellent high temperature bonding characteristics in the fully cured state and improved peel strength and adhesive fracture resistance physical property characteristics. The process for making the improved adhesive involves preparing the rubber-containing amic acid prepolymer by chemically reacting an amine-terminated elastomer and an aromatic diamine with an aromatic dianhydride with which a reactive chain stopper anhydride has been mixed, and utilizing solvent or mixture of solvents for the reaction.

  1. Ceramic composite protection for turbine disc bursts. [for the A-300 aircraft

    NASA Technical Reports Server (NTRS)

    Gardner, P. B.

    1977-01-01

    Ceramic composite turbine disc protection panels for the A300B were developed using armor technology. Analytical predictions for modifying the ballistic projectile armor system were verified by a test program conducted to qualify the rotor containment system. With only a slight change in the areal density of the armor system a more than two-fold increase in kinetic energy protection level was achieved. Thickness of the fiberglass reinforced plastic backing material was increased to achieve an optimum ratio of ceramic thickness to backing thickness for the different ballistic defeat condition.

  2. Advanced composite structural concepts and materials technologies for primary aircraft structures: Advanced material concepts

    NASA Technical Reports Server (NTRS)

    Lau, Kreisler S. Y.; Landis, Abraham L.; Chow, Andrea W.; Hamlin, Richard D.

    1993-01-01

    To achieve acceptable performance and long-term durability at elevated temperatures (350 to 600 F) for high-speed transport systems, further improvements of the high-performance matrix materials will be necessary to achieve very long-term (60,000-120,000 service hours) retention of mechanical properties and damage tolerance. This report emphasizes isoimide modification as a complementary technique to semi-interpenetrating polymer networks (SIPN's) to achieve greater processibility, better curing dynamics, and possibly enhanced thermo-mechanical properties in composites. A key result is the demonstration of enhanced processibility of isoimide-modified linear and thermo-setting polyimide systems.

  3. Multilevel probabilistic approach to evaluate manufacturing defect in composite aircraft structures

    SciTech Connect

    Caracciolo, Paola

    2014-05-15

    In this work it is developed a reliable approach and its feasibility to the design and analysis of a composite structures. The metric is compared the robustness and reliability designs versus the traditional design, to demonstrate the gain that can be achieved with a probabilistic approach. The use of the stochastic approach of the uncertain parameteters in combination with the multi-scale levels analysis is the main objective of this paper. The work is dedicated to analyze the uncertainties in the design, tests, manufacturing process, and key gates such as materials characteristic.

  4. Innovative fabrication processing of advanced composite materials concepts for primary aircraft structures

    NASA Technical Reports Server (NTRS)

    Kassapoglou, Christos; Dinicola, Al J.; Chou, Jack C.

    1992-01-01

    The autoclave based THERM-X(sub R) process was evaluated by cocuring complex curved panels with frames and stiffeners. The process was shown to result in composite parts of high quality with good compaction at sharp radius regions and corners of intersecting parts. The structural properties of the postbuckled panels fabricated were found to be equivalent to those of conventionally tooled hand laid-up parts. Significant savings in bagging time over conventional tooling were documented. Structural details such as cocured shear ties and embedded stiffener flanges in the skin were found to suppress failure modes such as failure at corners of intersecting members and skin stiffeners separation.

  5. Novel approaches for alleviation of electrical hazards of graphite-fiber composites. [aircraft safety

    NASA Technical Reports Server (NTRS)

    Ramohalli, K.

    1979-01-01

    Four basically different approaches were considered: gasification of fibers, retention in the matrix, clumping to prevent entrainment, and electrical insulation of fibers. The techniques used to achieve them are described in some detail. These involved surface treatment of fibers to improve the wettability of fibers and coating the fibers with the selected substances before laying them up for composite fabrication. Thermogravimetric analyses were performed on the plain and treated fibers in inert (nitrogen, argon) and reactive (air) atmospheres. The treated fibers embedded in epoxy were ignited in a Bunsen flame to determine the efficiency of these treatments. A simple apparatus was assembled to detect the time for the first short circuit (in a typical electrical circuit) when exposed to the combustion products from a graphite fiber composite fire. The state-of-the-art and treated fibers cast in typical epoxy were burned and ranked for potential success. It was inferred that the gasification schemes appear promising when reduction or oxidation is tried. It was also found that some very promising candidates were available for the clumping and for the electrical insulation of fibers.

  6. Design and demonstration of automated data analysis algorithms for ultrasonic inspection of complex composite panels with bonds

    NASA Astrophysics Data System (ADS)

    Aldrin, John C.; Forsyth, David S.; Welter, John T.

    2016-02-01

    To address the data review burden and improve the reliability of the ultrasonic inspection of large composite structures, automated data analysis (ADA) algorithms have been developed to make calls on indications that satisfy the detection criteria and minimize false calls. The original design followed standard procedures for analyzing signals for time-of-flight indications and backwall amplitude dropout. However, certain complex panels with varying shape, ply drops and the presence of bonds can complicate this interpretation process. In this paper, enhancements to the automated data analysis algorithms are introduced to address these challenges. To estimate the thickness of the part and presence of bonds without prior information, an algorithm tracks potential backwall or bond-line signals, and evaluates a combination of spatial, amplitude, and time-of-flight metrics to identify bonded sections. Once part boundaries, thickness transitions and bonded regions are identified, feature extraction algorithms are applied to multiple sets of through-thickness and backwall C-scan images, for evaluation of both first layer through thickness and layers under bonds. ADA processing results are presented for a variety of complex test specimens with inserted materials and other test discontinuities. Lastly, enhancements to the ADA software interface are presented, which improve the software usability for final data review by the inspectors and support the certification process.

  7. Nondestructive testing potential evaluation of a terahertz frequency-modulated continuous-wave imager for composite materials inspection

    NASA Astrophysics Data System (ADS)

    Cristofani, Edison; Friederich, Fabian; Wohnsiedler, Sabine; Matheis, Carsten; Jonuscheit, Joachim; Vandewal, Marijke; Beigang, René

    2014-03-01

    The sub-terahertz (THz) frequency band has proved to be a noteworthy option for nondestructive testing (NDT) of nonmetal aeronautics materials. Composite structures or laminates can be inspected for foreign objects (water or debris), delaminations, debonds, etc., using sub-THz sensors during the manufacturing process or maintenance. Given the harmless radiation to the human body of this frequency band, no special security measures are needed for operation. Moreover, the frequency-modulated continuous-wave sensor used in this study offers a very light, compact, inexpensive, and high-performing solution. An automated two-dimensional scanner carrying three sensors partially covering the 70- to 320-GHz band is operated, using two complementary measurement approaches: conventional focused imaging, where focusing lenses are used; and synthetic aperture (SA) or unfocused wide-beam imaging, for which lenses are no longer needed. Conventional focused imagery offers finer spatial resolutions but imagery is depth-limited due to the beam waist effect, whereas SA measurements allow imaging of thicker samples with depth-independent but coarser spatial resolutions. The present work is a compendium of a much larger study and describes the key technical aspects of the proposed imaging techniques and reports on results obtained from human-made samples (A-sandwich, C-sandwich, solid laminates) which include diverse defects and damages typically encountered in aeronautics multilayered structures. We conclude with a grading of the achieved results in comparison with measurements performed by other NDT techniques on the same samples.

  8. Design and Optimization of a Composite Canard Control Surface of an Advanced Fighter Aircraft under Static Loading

    NASA Astrophysics Data System (ADS)

    Shrivastava, Sachin; Mohite, P. M.

    2015-01-01

    The minimization of weight and maximization of payload is an ever challenging design procedure for air vehicles. The present study has been carried out with an objective to redesign control surface of an advanced all-metallic fighter aircraft. In this study, the structure made up of high strength aluminum, titanium and ferrous alloys has been attempted to replace by carbon fiber composite (CFC) skin, ribs and stiffeners. This study presents an approach towards development of a methodology for optimization of first-ply failure index (FI) in unidirectional fibrous laminates using Genetic-Algorithms (GA) under quasi-static loading. The GAs, by the application of its operators like reproduction, cross-over, mutation and elitist strategy, optimize the ply-orientations in laminates so as to have minimum FI of Tsai-Wu first-ply failure criterion. The GA optimization procedure has been implemented in MATLAB and interfaced with commercial software ABAQUS using python scripting. FI calculations have been carried out in ABAQUS with user material subroutine (UMAT). The GA's application gave reasonably well-optimized ply-orientations combination at a faster convergence rate. However, the final optimized sequence of ply-orientations is obtained by tweaking the sequences given by GA's based on industrial practices and experience, whenever needed. The present study of conversion of an all metallic structure to partial CFC structure has led to 12% of weight reduction. Therefore, the approach proposed here motivates designer to use CFC with a confidence.

  9. General Motors Corporation and Pacific Northwest Laboratory staff exchange: Inspection of case hardened steels and metal-matrix composites

    SciTech Connect

    Good, M.S.; Rogers, D.D.

    1993-10-01

    Staff exchanges, such as the one described in this report, are intended to facilitate communication and collaboration among scientists and engineers at Department of Energy (DOE) laboratories, in US industry, and academia. Funding support for these exchanges is provided by the DOE, Office of Energy Research, Laboratory Technology Transfer Program. The exchanges offer the opportunity for the laboratories to transfer technology and expertise to industry, gain a perspective on industry`s problems, and develop the basis for further cooperative efforts through Cooperative Research and Development Agreements (CRADAs) or other mechanisms. The objectives of this report were as follows: for Pacific Northwest Laboratory (PNL) staff to present technology to General Motors (GM) staff on nondestructive measurement of hardened steel components and uniformity of particle dispersion in metal-matrix composites for evaluation for possible application in GM`s manufacturing processes; for GM staff to discuss with PNL staff common manufacturing processes, metallurgy, and flaw criteria for hardening of various components and manufacturing of metal-matrix composites; to provide an initial step in building a long-term collaborative relationship between PNL and GM. Information in this report on the staff exchange of PNL staff with GM Corporation includes the purpose and objectives, a summary of activities, significant accomplishments, significant problems, industry benefits realized, recommended follow-on work and potential benefits from that work, and three appendixes. Appendix A is a description of ultrasonic backscatter technology and its applications to the two nondestructive inspection interests defined by GM. Appendix B is a list of key contacts and the schedule of activities pertaining to the staff exchange. Appendix C is an article from American Society for Metals News relating to sensor needs.

  10. Time-temperature-stress capabilities of composites for supersonic cruise aircraft applications

    NASA Technical Reports Server (NTRS)

    Haskins, J. F.; Kerr, J. R.; Stein, B. A.

    1976-01-01

    A range of baseline properties was determined for representatives of 5 composite materials systems: B/Ep, Gr/Ep, B/PI, Gr/PI, and B/Al. Long-term exposures are underway in static thermal environments and in ones which simultaneously combine programmed thermal histories and mechanical loading histories. Selected results from the environmental exposure studies with emphasis placed on the 10,000-hour thermal aging data are presented. Results of residual strength determinations and changes in physcial and chemical properties during high temperature aging are discussed and illustrated using metallographic, fractographic and thermomechanical analyses. Some initial results of the long-term flight simulation tests are also included.

  11. Experimental and numerical analysis of defects in composite panels used in business aircrafts interior

    NASA Astrophysics Data System (ADS)

    Ruiz, Edu; Courteau-Godmaire, H.; Fotsing, R.; Billotte, C.; Levesque, M.

    2016-05-01

    This paper provides an optical characterization and numerical prediction of local deformations appearing on the visible side of composite sandwich panels used for interior furniture of business airplanes. During manufacturing of furniture panels, metallic inserts are bonded inside the sandwich panel using an epoxy adhesive. Surface defects appear on the visible side of the panels due to curing of the adhesive, but also because of temperature gradients and humidity during manufacturing and in service. This paper presents an optical characterization based on deflectometry principle, that allows qualitative and quantitative analyses of the surface deformations in 3-dimensions. In addition, this paper presents a parametric model based on finite elements to predict the formation of surface defects using ABAQUS. A comparison is presented between the experimental observations and numerical predictions with good agreement between them.

  12. Challenges and payoff of composites in transport aircraft: 777 empennage and future applications

    NASA Technical Reports Server (NTRS)

    Quinlivan, John

    1993-01-01

    The Boeing 777 is the first of a new family of wide body airplanes. The new large twin is sized to accommodate 360 to 390 passengers in typical two-class configurations and planned growth beyond that. The 777 offers airlines three engine options, extremely attractive operating costs, and compatibility with existing airport gates and taxiways. The 777 has a wingspan of nearly 197 feet and is offered with a wing-tip folding mechanism that will reduce the span to 156 feet. Extensive use of advance composite is included in the 777. The application range from fiberglass fairing to primary structures. The 777 empennage includes vertical fin and a horizontal stabilizer. The material used for the empennage is a new, toughened epoxy materials. The material provides outstanding resistance to impact damage.

  13. Aging Aircraft NDI Development and Demonstration Center (AANC): An overview

    SciTech Connect

    Walter, P.L.

    1991-01-01

    A major center with emphasis on validation of nondestructive inspection techniques for aging aircraft, the Aging Aircraft NDI Development and Demonstration Center (AANC), has been funded by the FAA at Sandia National Laboratories. The Center has been assigned specific tasks in developing techniques for the nondestructive inspection of static engine parts, assessing inspection reliability (POD experiments), developing test beds for nondestructive inspection validation, maintaining a FAA library of characterized aircraft structural test specimens, and leasing a hangar to house a high flight cycle transport aircraft for use as a full scale test bed. 3 refs.

  14. Development of structural health monitoring systems for composite bonded repairs on aircraft structures

    NASA Astrophysics Data System (ADS)

    Galea, Stephen C.; Powlesland, Ian G.; Moss, Scott D.; Konak, Michael J.; van der Velden, Stephen P.; Stade, Bryan; Baker, Alan A.

    2001-08-01

    The application of bonded composite patches to repair or reinforce defective metallic structures is becoming recognized as a very effective versatile repair procedure for many types of problems. Immediate applications of bonded patches are in the fields of repair of cracking, localized reinforcement after removal of corrosion damage and for reduction of fatigue strain. However, bonded repairs to critical components are generally limited due to certification concerns. For certification and management of repairs to critical structure, the Smart Patch approach may be an acceptable solution from the airworthiness prospective and be cost effective for the operator and may even allow some relaxation of the certification requirements. In the most basic form of the Smart Patch in-situ sensors can be used as the nerve system to monitor in service the structural condition (health or well-being) of the patch system and the status of the remaining damage in the parent structure. This application would also allow the operator to move away from current costly time-based maintenance procedures toward real-time health condition monitoring of the bonded repair and the repaired structure. TO this end a stand-alone data logger device, for the real-time health monitoring of bonded repaired systems, which is in close proximity to sensors on a repair is being developed. The instrumentation will measure, process and store sensor measurements during flight and then allow this data to be up-loaded, after the flight, onto a PC, via remote (wireless) data access. This paper describes two in-situ health monitoring systems which will be used on a composite bonded patch applied to an F/A-18. The two systems being developed consists of a piezoelectric (PVDF) film-based and a conventional electrical-resistance foil strain gauge-based sensing system. The latter system uses a primary cell (Lithium- based battery) as the power source, which should enable an operating life of 1-2 years. The patch

  15. Evaluation of Ceramic Matrix Composite Technology for Aircraft Turbine Engine Applications

    NASA Technical Reports Server (NTRS)

    Halbig, Michael C.; Jaskowiak, Martha H.; Kiser, James D.; Zhu, Dongming

    2013-01-01

    The goals of the NASA Environmentally Responsible Aviation (ERA) Project are to reduce the NO(x) emissions, fuel burn, and noise from turbine engines. In order to help meet these goals, commercially-produced ceramic matrix composite (CMC) components and environmental barrier coatings (EBCs) are being evaluated as parts and panels. The components include a CMC combustor liner, a CMC high pressure turbine vane, and a CMC exhaust nozzle as well as advanced EBCs that are tailored to the operating conditions of the CMC combustor and vane. The CMC combustor (w/EBC) could provide 2700 F temperature capability with less component cooling requirements to allow for more efficient combustion and reductions in NOx emissions. The CMC vane (w/EBC) will also have temperature capability up to 2700 F and allow for reduced fuel burn. The CMC mixer nozzle will offer reduced weight and improved mixing efficiency to provide reduced fuel burn. The main objectives are to evaluate the manufacturability of the complex-shaped components and to evaluate their performance under simulated engine operating conditions. Progress in CMC component fabrication, evaluation, and testing is presented in which the goal is to advance from the proof of concept validation (TRL 3) to a system/subsystem or prototype demonstration in a relevant environment (TRL 6).

  16. Modelling Strategies for Predicting the Residual Strength of Impacted Composite Aircraft Fuselages

    NASA Astrophysics Data System (ADS)

    Lachaud, Frederic; Espinosa, Christine; Michel, Laurent; Rahme, Pierre; Piquet, Robert

    2015-12-01

    Aeronautic Certification rules established for the metallic materials are not convenient for the composite structures concerning the resistance against impact. The computer-based design is a new methodology that is thought about to replace the experimental tests. It becomes necessary for numerical methods to be robust and predictive for impact. Three questions are addressed in this study: (i) can a numerical model be "mechanically intrinsic" to predict damage after impact, (ii) can this model be the same for a lab sample and a large structure, and (iii) can the numerical model be predictive enough to predict the Compression After Impact (CAI)? Three different computational strategies are used and compared: a Cohesive Model (CM), a Continuous Damage Model (CDM) coupling failure modes and damage, and a Mixed Methodology (MM) using the CDM for delamination initiation and the CM for cracks propagation. The first attempts to use the Smooth Particle Hydrodynamics method are presented. Finally, impact on a fuselage is modelled and a numerical two-stage strategy is developed to predict the CAI.

  17. Acoustic-sensor-based detection of damage in composite aircraft structures

    NASA Astrophysics Data System (ADS)

    Foote, Peter; Martin, Tony; Read, Ian

    2004-03-01

    Acoustic emission detection is a well-established method of locating and monitoring crack development in metal structures. The technique has been adapted to test facilities for non-destructive testing applications. Deployment as an operational or on-line automated damage detection technology in vehicles is posing greater challenges. A clear requirement of potential end-users of such systems is a level of automation capable of delivering low-level diagnosis information. The output from the system is in the form of "go", "no-go" indications of structural integrity or immediate maintenance actions. This level of automation requires significant data reduction and processing. This paper describes recent trials of acoustic emission detection technology for the diagnosis of damage in composite aerospace structures. The technology comprises low profile detection sensors using piezo electric wafers encapsulated in polymer film ad optical sensors. Sensors are bonded to the structure"s surface and enable acoustic events from the loaded structure to be located by triangulation. Instrumentation has been enveloped to capture and parameterise the sensor data in a form suitable for low-bandwidth storage and transmission.

  18. Advanced composites structural concepts and materials technologies for primary aircraft structures: Structural response and failure analysis

    NASA Technical Reports Server (NTRS)

    Dorris, William J.; Hairr, John W.; Huang, Jui-Tien; Ingram, J. Edward; Shah, Bharat M.

    1992-01-01

    Non-linear analysis methods were adapted and incorporated in a finite element based DIAL code. These methods are necessary to evaluate the global response of a stiffened structure under combined in-plane and out-of-plane loading. These methods include the Arc Length method and target point analysis procedure. A new interface material model was implemented that can model elastic-plastic behavior of the bond adhesive. Direct application of this method is in skin/stiffener interface failure assessment. Addition of the AML (angle minus longitudinal or load) failure procedure and Hasin's failure criteria provides added capability in the failure predictions. Interactive Stiffened Panel Analysis modules were developed as interactive pre-and post-processors. Each module provides the means of performing self-initiated finite elements based analysis of primary structures such as a flat or curved stiffened panel; a corrugated flat sandwich panel; and a curved geodesic fuselage panel. This module brings finite element analysis into the design of composite structures without the requirement for the user to know much about the techniques and procedures needed to actually perform a finite element analysis from scratch. An interactive finite element code was developed to predict bolted joint strength considering material and geometrical non-linearity. The developed method conducts an ultimate strength failure analysis using a set of material degradation models.

  19. Effects of simulated lightning on composite and metallic joints

    NASA Technical Reports Server (NTRS)

    Howell, W. E.; Plumer, J. A.

    1982-01-01

    The effects of simulated lightning strikes and currents on aircraft bonded joints and access/inspection panels were investigated. Both metallic and composite specimens were tested. Tests on metal fuel feed through elbows in graphite/epoxy structures were evaluated. Sparking threshold and residual strength of single lap bonded joints and sparking threshold of access/inspection panels and metal fuel feed through elbows are reported.

  20. Mission management aircraft operations manual

    NASA Technical Reports Server (NTRS)

    1992-01-01

    This manual prescribes the NASA mission management aircraft program and provides policies and criteria for the safe and economical operation, maintenance, and inspection of NASA mission management aircraft. The operation of NASA mission management aircraft is based on the concept that safety has the highest priority. Operations involving unwarranted risks will not be tolerated. NASA mission management aircraft will be designated by the Associate Administrator for Management Systems and Facilities. NASA mission management aircraft are public aircraft as defined by the Federal Aviation Act of 1958. Maintenance standards, as a minimum, will meet those required for retention of Federal Aviation Administration (FAA) airworthiness certification. Federal Aviation Regulation Part 91, Subparts A and B, will apply except when requirements of this manual are more restrictive.

  1. Pulsed eddy current inspection of CF-188 inner wing spar

    NASA Astrophysics Data System (ADS)

    Horan, Peter Francis

    Royal Canadian Air Force (RCAF) CF-188 Hornet aircraft engineering authorities have stated a requirement for a Non-Destructive Evaluation (NDE) technique to detect Stress Corrosion Cracking (SCC) in the inner wing spars without fastener or composite wing skin removal. Current radiographic inspections involve significant aircraft downtime, and Pulsed Eddy Current (PEC) inspection is proposed as a solution. The aluminum inner wing spars of CF-188 Hornet aircraft may undergo stress corrosion cracking (SCC) along the spar between the fasteners that secure carbon-fiber/ epoxy composite skin to the wing. Inspection of the spar through the wing skin is required to avoid wing disassembly. The thickness of the wing skin varies between 8 and 20 mm (0.3 to 0.8 inch) and fasteners may be either titanium or ferrous. PEC generated by a probe centered over a fastener, demonstrates capability of detecting simulated cracks within spars with the wing skin present. Comparison of signals from separate sensors, mounted to either side of the excitation coil, is used to detect differences in induced eddy current fields, which arise in the presence of cracks. To overcome variability in PEC signal response due to variation in 1) skin thickness, 2) fastener material and size, and 3) centering over fasteners, a large calibration data set is acquired. Multi-dimensional scores from a Modified Principal Components Analysis (PCA) of the data are reduced to one dimension (1D) using a Discriminant Analysis method. Under inspection conditions, calibrated PCA scores combined with discriminant analysis permit rapid real time go/no-go PEC detection of cracks in CF-188 inner wing spar. Probe designs using both pickup coils and Giant Magnetoresistive (GMR) sensors were tested on samples with the same ferrous and titanium fasteners found on the CF-188. Flaws were correctly detected at lift-offs of up to 21mm utilizing a variety of insulating skin materials simulating the carbon-fibre reinforced polymer

  2. Structural health monitoring and impact detection for primary aircraft structures

    NASA Astrophysics Data System (ADS)

    Kosters, Eric; van Els, Thomas J.

    2010-04-01

    The increasing use of thermoplastic carbon fiber-reinforced plastic (CFRP) materials in the aerospace industry for primary aircraft structures, such as wing leading-edge surfaces and fuselage sections, has led to rapid growth in the field of structural health monitoring (SHM). Impact, vibration, and load can all cause failure, such as delamination and matrix cracking, in composite materials. Moreover, the internal material damage can occur without being visible to the human eye, making inspection of and clear insight into structural integrity difficult using currently available evaluation methods. Here, we describe the detection of impact and its localization in materials and structures by high-speed interrogation of multiple-fiber Bragg grating (FBG) sensors mounted on a composite aircraft component.

  3. A hybrid UTD-MM analysis of the radiation from a composite slot-blade cavity-backed antenna on realistic aircraft configurations

    NASA Astrophysics Data System (ADS)

    Tseng, Huan-Wan; Pathak, Prabhakar H.

    1999-05-01

    A hybrid method which combines the uniform geometrical theory of diffraction (UTD) with a numerical moment method (MM) technique is presented for the analysis of the radiation from a composite slot-blade cavity-backed antenna located on realistic aircraft configurations. The excitation of the antenna is due to a delta gap generator in a thin-wire probe feed that is placed inside a rectangular cavity. The MM procedure is used to solve coupled integral equations that are formulated for the unknown equivalent electric current distribution on the blade and the unknown equivalent magnetic current distribution over the slot, when this slot-blade antenna configuration resides on an infinite ground plane. The UTD is next used to efficiently and accurately calculate the radiation from these equivalent current distributions for the slot-blade antenna combination when the latter are now located on realistic aircraft geometries instead of a fiat ground plane. Calculated radiation patterns of the composite slot-blade cavity-backed antennas placed on a Boeing 737 commercial airplane and an F-16 fighter aircraft are presented to illustrate the utility of this hybrid approach.

  4. CFRP sandwiched facesheets inspected by pulsed thermography

    NASA Astrophysics Data System (ADS)

    Li, Huijuan; Huo, Yan; Cai, Liangxu; Huang, Zhenhua

    2010-10-01

    Carbon fiber reinforced polymer (CFRP) has been always used in aerospace, Sandwiched structures composed by a honeycomb core between two multi-layer CFRP facesheets are very common on aerospace parts. As to the application of the CFRP sandwiched facesheets is extended, The demand for quality control of CFRP sandwiched composites is increasing, Infrared thermography is one of several non-destructive testing techniques which can be used for defect detection in aircraft materials such as carbon-fibre-reinforced composites. Infrared thermography can be potentially useful, as it is quick, real time, non-contact and can examine over a relatively large area in one inspection procedure. The technique is based on heating the sample surface with different heat sources and monitoring the surface temperature of the sample with an IR camera, any abnormal behavior of the surface temperature distribution indicates the subsurface defect. This kind of structure is normally affected by anomalies such as delaminations, disbonding, water ingressing to the core. in this paper, several different kinds of defects which are of various size and depth below the test surface are planted in the CFRP composites, the Teflon inserts between the plies in the facesheet represents the delaminations, the Teflon inserts between the inner facesheet and adhensive or between adhensive and core are simulated disbonding in the composites, they are all tested by pulsed thermography, meanwhile, these samples are also inspected by ultrasonic testing, compare with each characteristic and the results got by these two different methods, it shows that pulsed thermography is an effective nondestructive technique for inspecting CFRP composites.

  5. 14 CFR 33.55 - Teardown inspection.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... STANDARDS: AIRCRAFT ENGINES Block Tests; Reciprocating Aircraft Engines § 33.55 Teardown inspection. After completing the endurance test— (a) Each engine must be completely disassembled; (b) Each component having an... established and recorded at the beginning of the test; and (c) Each engine component must conform to the...

  6. 14 CFR 33.55 - Teardown inspection.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... STANDARDS: AIRCRAFT ENGINES Block Tests; Reciprocating Aircraft Engines § 33.55 Teardown inspection. After completing the endurance test— (a) Each engine must be completely disassembled; (b) Each component having an... established and recorded at the beginning of the test; and (c) Each engine component must conform to the...

  7. 14 CFR 33.55 - Teardown inspection.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... STANDARDS: AIRCRAFT ENGINES Block Tests; Reciprocating Aircraft Engines § 33.55 Teardown inspection. After completing the endurance test— (a) Each engine must be completely disassembled; (b) Each component having an... established and recorded at the beginning of the test; and (c) Each engine component must conform to the...

  8. 14 CFR 33.55 - Teardown inspection.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... STANDARDS: AIRCRAFT ENGINES Block Tests; Reciprocating Aircraft Engines § 33.55 Teardown inspection. After completing the endurance test— (a) Each engine must be completely disassembled; (b) Each component having an... established and recorded at the beginning of the test; and (c) Each engine component must conform to the...

  9. 14 CFR 33.55 - Teardown inspection.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... STANDARDS: AIRCRAFT ENGINES Block Tests; Reciprocating Aircraft Engines § 33.55 Teardown inspection. After completing the endurance test— (a) Each engine must be completely disassembled; (b) Each component having an... established and recorded at the beginning of the test; and (c) Each engine component must conform to the...

  10. 14 CFR 33.93 - Teardown inspection.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... STANDARDS: AIRCRAFT ENGINES Block Tests; Turbine Aircraft Engines § 33.93 Teardown inspection. (a) After completing the endurance testing of § 33.87 (b), (c), (d), (e), or (g) of this part, each engine must be...) After completing the endurance testing of § 33.87(f), each engine must be completely disassembled,...

  11. 42 CFR 71.44 - Disinsection of aircraft.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 1 2012-10-01 2012-10-01 false Disinsection of aircraft. 71.44 Section 71.44 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES QUARANTINE, INSPECTION, LICENSING FOREIGN QUARANTINE Requirements Upon Arrival at U.S. Ports: Sanitary Inspection § 71.44 Disinsection of aircraft. (a) The Director may...

  12. Program for establishing long-time flight service performance of composite materials in the center wing structure of C-130 aircraft. Phase 3: Fabrication

    NASA Technical Reports Server (NTRS)

    Harvill, W. E.; Kays, A. O.

    1974-01-01

    The manufacturing plan for three C-130 aircraft center wing box test articles, selectively reinforced with boron-epoxy composites, is outlined for the following tasks: (1) tooling; (2) metal parts fabrication: (3) reinforcing laminate fabrication; (4) laminate-to-metal parts bonding; and (5) wing box assembly. The criteria used for reliability and quality assurance are discussed, and several solutions to specific manufacturing problems encountered during fabrication are given. For Vol. 1, see N73-13011; for Vol. 2, see N73-22929.

  13. 14 CFR 31.41 - Inspection provisions.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Inspection provisions. 31.41 Section 31.41 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: MANNED FREE BALLOONS Design Construction § 31.41 Inspection provisions. There must be a means...

  14. Emerging NDE Technology for aging aircraft

    SciTech Connect

    Moore, D.G.; Perry, R.L.

    1998-03-01

    This paper presents an overview of several emerging nondestructive evaluation technologies that are being employed or considered for use to inspect commercial transport, commuter aircraft and military aircraft. An overview of the Federal Aviation Administration (FAA) Airworthiness Assurance NDI Validation Center (AANC) is described and how AANC teams with industry, universities, and other federal entities to assess these technologies.

  15. Aging aircraft NDI Development and Demonstration Center (AANC): An overview

    NASA Astrophysics Data System (ADS)

    Walter, Patrick L.

    1992-07-01

    A major center with emphasis on validation of nondestructive inspection (NDI) techniques for aging aircraft, the Aging Aircraft NDI Development and Demonstration Center (AANC), has been funded by the FAA at Sandia National Laboratories. The Center has been assigned specific tasks in developing techniques for the nondestructive inspection of static engine parts, assessing inspection reliability (POD experiments), developing testbeds for NDI validation, maintaining a FAA library of characterized aircraft structural test specimens, and leasing a hangar to house a high flight cycle transport aircraft for use as a full scale test bed.

  16. 14 CFR 33.90 - Initial maintenance inspection test.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Initial maintenance inspection test. 33.90 Section 33.90 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: AIRCRAFT ENGINES Block Tests; Turbine Aircraft Engines § 33.90 Initial...

  17. 14 CFR 33.90 - Initial maintenance inspection test.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Initial maintenance inspection test. 33.90 Section 33.90 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: AIRCRAFT ENGINES Block Tests; Turbine Aircraft Engines § 33.90 Initial...

  18. 14 CFR 33.90 - Initial maintenance inspection test.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Initial maintenance inspection test. 33.90 Section 33.90 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: AIRCRAFT ENGINES Block Tests; Turbine Aircraft Engines § 33.90 Initial...

  19. Development, manufacturing, and test of graphite-epoxy composite spoilers for flight service on 737 transport aircraft

    NASA Technical Reports Server (NTRS)

    Stoecklin, R. L.

    1976-01-01

    A total of 114 spoiler units were fabricated in a production shop environment, utilizing three graphite epoxy material systems. Production planning paper was generated for each spoiler unit to completely document each production step of each spoiler unit. The graphite epoxy skins were laid up on production tooling using both mechanical and hand layup techniques. Inspection techniques utilized MRB type assessment in the abscence of quality requirements. Each completed spoiler was subjected to ultrasonic inspection utilizing a multicolor recording system that documented each inspection result. In addition, one static test spoiler was sectioned after the test to examine the adhesive filleting to the honeycomb core. Visual examination of the cured adhesives showed excellent results.

  20. ACEE Composite Structures Technology: Review of selected NASA research on composite materials and structures

    NASA Technical Reports Server (NTRS)

    1984-01-01

    The NASA Aircraft Energy Efficiency (ACEE) Composite Primary Aircraft Structures Program was designed to develop technology for advanced composites in commercial aircraft. Research on composite materials, aircraft structures, and aircraft design is presented herein. The following parameters of composite materials were addressed: residual strength, damage tolerance, toughness, tensile strength, impact resistance, buckling, and noise transmission within composite materials structures.

  1. 49 CFR 1540.107 - Submission to screening and inspection.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 9 2010-10-01 2010-10-01 false Submission to screening and inspection. 1540.107... screening and inspection. (a) No individual may enter a sterile area or board an aircraft without submitting to the screening and inspection of his or her person and accessible property in accordance with...

  2. An Overview of the NASA Spring/Summer 2008 Arctic Campaign - ARCTAS (Arctic Research of the Composition of the Troposphere from Aircraft and Satellites)

    NASA Technical Reports Server (NTRS)

    Jacob, Daniel J.; Clarke, Antony; Crawford, James H.; Dibbs, Jack; Ferrare, Richard A.; Hostetler, Chris A.; Maring, Hal; Russell, Philip B.; Singh, Hanwant B.

    2008-01-01

    ARCTAS (Arctic Research of the Composition of the Troposphere from Aircraft and Satellites) is a major NASA led airborne field campaign being performed in the spring and summer of 2008 at high latitudes (http://cloud1.arc.nasa.gov/arctas/). ARCTAS is a part of the International Polar Year program and its activities are closely coordinated with multiple U. S. (NOAA, DOE), Canadian, and European partners. Observational data from an ensemble of aircraft, surface, and satellite sensors are closely integrated with models of atmospheric chemistry and transport in this experiment. Principal NASA airborne platforms include a DC-8 for detailed atmospheric composition studies, a P-3 that focuses on aerosols and radiation, and a B-200 that is dedicated to remote sensing of aerosols. Satellite validation is a central activity in all these platforms and is mainly focused on CALIPSO, Aura, and Aqua satellites. Major ARCTAS themes are: (1) Long-range transport of pollution to the Arctic including arctic haze, tropospheric ozone, and persistent pollutants such as mercury; (2) Boreal forest fires and their implications for atmospheric composition and climate; (3) Aerosol radiative forcing from arctic haze, boreal fires, surface-deposited black carbon, and other perturbations; and (4) Chemical processes with focus on ozone, aerosols, mercury, and halogens. The spring deployment (April) is presently underway and is targeting plumes of anthropogenic and biomass burning pollution and dust from Asia and North America, arctic haze, stratosphere-troposphere exchange, and ozone photochemistry involving HOx and halogen radicals. The summer deployment (July) will target boreal forest fires and summertime photochemistry. The ARCTAS mission is providing a critical link to enhance the value of NASA satellite observations for Earth science. In this talk we will discuss the implementation of this campaign and some preliminary results.

  3. Analytical and experimental investigation of aircraft metal structures reinforced with filamentary composites. Phase 2: Structural fatigue, thermal cycling, creep, and residual strength

    NASA Technical Reports Server (NTRS)

    Blichfeldt, B.; Mccarty, J. E.

    1972-01-01

    Specimens representative of metal aircraft structural components reinforced with boron filamentary composites were manufactured and tested under cyclic loading, cyclic temperature, or continuously applied loading to evaluate some of the factors that affect structural integrity under cyclic conditions. Bonded, stepped joints were used throughout to provide composite-to-metal transition regions at load introduction points. Honeycomb panels with titanium or aluminum faces reinforced with unidirectional boron composite were fatigue tested at constant amplitude under completely reversed loading. Results indicated that the matrix material was the most fatigue-sensitive part of the design, with debonding initiating in the stepped joints. However, comparisons with equal weight all-metal specimens show a 10 to 50 times improved fatigue life. Fatigue crack propagation and residual strength were studied for several different stiffened panel concepts, and were found to vary considerably depending on the configuration. Composite-reinforced metal specimens were also subjected to creep and thermal cycling tests. Thermal cycling of stepped joint tensile specimens resulted in a ten percent decrease in residual strength after 4000 cycles.

  4. In-Flight Chemical Composition Observations of Aircraft Emissions using a High-Resolution Time-of-Flight Aerosol Mass Spectrometer

    NASA Astrophysics Data System (ADS)

    Ziemba, L. D.; Martin, R.; Moore, R.; Shook, M.; Thornhill, K. L., II; Winstead, E.; Anderson, B. E.

    2015-12-01

    Commercial aircraft are an important source of aerosols to the upper troposphere. The microphysical and chemical properties of these emitted aerosols govern their ability to act as ice nuclei, both in near-field contrails and for cirrus formation downstream. During the ACCESS-II (Alternative Fuel Effects on Contrails and Cruise Emissions) campaign, NASA DC-8 CFM56-2-C1 engine emissions were sampled systematically at a range of cruise-relevant thrust levels and at several altitudes. Sampling was done aboard the NASA HU-25 Falcon aircraft, which was equipped with a suite of aerosol and gas-phase instruments focused on assessing the effects of burning different fuel mixtures on aerosol properties and their associated contrails. Here we present in-flight measurements of particle chemical composition made by a High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS). The AMS was able to sufficiently resolve near-field (within 100m) aircraft emissions plumes. Low-sulfur HEFA (hydro-processed esters and fatty-acids) and JetA fuels yielded particles that contained 11 and 8% sulfate, respectively, compared to 30% sulfate contribution for traditional JetA fuel. Each of the fuels produced organic aerosol with similarly low oxygen content. Lubrication oils, which are not a combustion product but result from leaks in the engine, were likely a dominant fraction of the measured organic mass based on mass-spectral marker analysis. These results are compared to similar engine conditions from ground-based testing.

  5. 19 CFR 122.51 - Aircraft of domestic origin registered in the U.S.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... Aircraft of domestic origin registered in the U.S. After Customs inspection of the aircraft, passengers, baggage and merchandise at the entry airport, commercial aircraft of domestic origin registered in the U.S... 19 Customs Duties 1 2013-04-01 2013-04-01 false Aircraft of domestic origin registered in the...

  6. 19 CFR 122.51 - Aircraft of domestic origin registered in the U.S.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... Aircraft of domestic origin registered in the U.S. After Customs inspection of the aircraft, passengers, baggage and merchandise at the entry airport, commercial aircraft of domestic origin registered in the U.S... 19 Customs Duties 1 2012-04-01 2012-04-01 false Aircraft of domestic origin registered in the...

  7. 19 CFR 122.51 - Aircraft of domestic origin registered in the U.S.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... Aircraft of domestic origin registered in the U.S. After Customs inspection of the aircraft, passengers, baggage and merchandise at the entry airport, commercial aircraft of domestic origin registered in the U.S... 19 Customs Duties 1 2014-04-01 2014-04-01 false Aircraft of domestic origin registered in the...

  8. 19 CFR 122.51 - Aircraft of domestic origin registered in the U.S.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... Aircraft of domestic origin registered in the U.S. After Customs inspection of the aircraft, passengers, baggage and merchandise at the entry airport, commercial aircraft of domestic origin registered in the U.S... 19 Customs Duties 1 2011-04-01 2011-04-01 false Aircraft of domestic origin registered in the...

  9. Robots for Aircraft Maintenance

    NASA Technical Reports Server (NTRS)

    1993-01-01

    Marshall Space Flight Center charged USBI (now Pratt & Whitney) with the task of developing an advanced stripping system based on hydroblasting to strip paint and thermal protection material from Space Shuttle solid rocket boosters. A robot, mounted on a transportable platform, controls the waterjet angle, water pressure and flow rate. This technology, now known as ARMS, has found commercial applications in the removal of coatings from jet engine components. The system is significantly faster than manual procedures and uses only minimal labor. Because the amount of "substrate" lost is minimal, the life of the component is extended. The need for toxic chemicals is reduced, as is waste disposal and human protection equipment. Users of the ARMS work cell include Delta Air Lines and the Air Force, which later contracted with USBI for development of a Large Aircraft Paint Stripping system (LARPS). LARPS' advantages are similar to ARMS, and it has enormous potential in military and civil aircraft maintenance. The technology may also be adapted to aircraft painting, aircraft inspection techniques and paint stripping of large objects like ships and railcars.

  10. Structural integrity in aircraft.

    NASA Technical Reports Server (NTRS)

    Hardrath, H. F.

    1973-01-01

    The paper reviews briefly the current design philosophies for achieving long, efficient, and reliable service in aircraft structures. The strengths and weaknesses of these design philosophies and their demonstrated records of success are discussed. The state of the art has not been developed to the point where designing can be done without major test inspection and maintenance programs. A broad program of research is proposed through which a viable computerized design scheme will be provided during the next decade. The program will organize and correlate existing knowledge on fatigue and fracture behavior, identify gaps in this knowledge, and guide specific research to upgrade design capabilities.

  11. Assessment of NDE needs for aging corporate and private aircraft

    NASA Astrophysics Data System (ADS)

    Reinhart, Eugene R.

    1998-03-01

    Considerable attention has been focused on the life extension of ageing military and commercial aircraft by the government and major aircraft fabricators. A vital, but often neglected segment of the aircraft industry is the are of inspecting ageing fleets of corporate and privately-owned aircraft. Many of these aircraft are inspected and maintained by the various FAA-approved repair stations located around the country. Nondestructive inspection (NDI) methods, equipment, and trained inspectors are a key aspect of maintaining these aircraft; however, there are currently several issues that need to be addressed by the private sector NDI community. Personnel training and certification to an accepted standard is critically needed in this industry since experience and capability in NDI can vary considerably between FAA stations and inspectors. Also, the updating of NDI methods are standards is needed. A review of these issues and suggestions for improvement are presented.

  12. Composition and Trends of Short-Lived Trace Gases in the UT/LS over Europe Observed by the CARIBIC Aircraft

    NASA Astrophysics Data System (ADS)

    Baker, A. K.; Brenninkmeijer, C. A.; Oram, D. E.; O'Sullivan, D. A.; Slemr, F.; Schuck, T. J.

    2009-12-01

    The CARIBIC project (Civil Aircraft for the Regular Investigation of the atmosphere Based on an Instrument Container) involves the monthly deployment of an instrument container equipped to make atmospheric measurements from aboard a commercial airliner, and has operated since 2005 from aboard a Lufthansa Airbus 340-600 . Measurements from the container include in-situ trace gas and aerosol analyses and the collection of aerosol and whole air samples for post-flight laboratory analysis. Measurements made from the sampling flasks include greenhouse gas (GHG), halocarbon and nonmethane hydrocarbon (NMHC) analysis. CARIBIC flights originate in Frankfurt, Germany with routes to India, East Asia, South America, North America and Africa, and typical aircraft cruising altitudes of 10-12km allow for the monitoring of the upper troposphere/lower stratosphere (UT/LS) along these routes. Data collected during the aircraft’s departure from and return to Frankfurt provide a 4 year time series of near-monthly measurements of the composition of the UT/LS above Europe. Here we present a discussion of the composition of short-lived trace gases in the whole air samples collected above Europe during CARIBIC flights. Over 150 air samples were collected between May 2005 and July 2009, or about 4 samples per month. Of the whole air samples collected, about 45% showed influence by stratospheric air (i.e. very low values of GHG, NMHC and halocarbons, elevated O3, high potential vorticity). The remaining samples were representative of the upper troposphere; back trajectories for these samples indicate that a little over half were collected in air masses that had been in the boundary layer within the previous 8 days. The predominant source regions for these samples were the Gulf of Mexico and continental North America. Owing to their wide range of chemical lifetimes and the varying composition of emissions, short-lived trace gases transported to the UT/LS can be useful indicators of source

  13. Online inspection

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An online line-scan imaging system capable of both hyperspectral and multispectral visible/near-infrared reflectance imaging was developed to inspect freshly slaughtered chickens on a processing line for wholesomeness. In-plant testing results indicated that the imaging inspection system achieved o...

  14. Aircraft Design

    NASA Technical Reports Server (NTRS)

    Bowers, Albion H. (Inventor); Uden, Edward (Inventor)

    2016-01-01

    The present invention is an aircraft wing design that creates a bell shaped span load, which results in a negative induced drag (induced thrust) on the outer portion of the wing; such a design obviates the need for rudder control of an aircraft.

  15. Aircraft Noise

    NASA Astrophysics Data System (ADS)

    Michel, Ulf; Dobrzynski, Werner; Splettstoesser, Wolf; Delfs, Jan; Isermann, Ullrich; Obermeier, Frank

    Aircraft industry is exposed to increasing public pressure aiming at a continuing reduction of aircraft noise levels. This is necessary to both compensate for the detrimental effect on noise of the expected increase in air traffic and improve the quality of living in residential areas around airports.

  16. The NASA Aircraft Energy Efficiency program

    NASA Technical Reports Server (NTRS)

    Klineberg, J. M.

    1979-01-01

    A review is provided of the goals, objectives, and recent progress in each of six aircraft energy efficiency programs aimed at improved propulsive, aerodynamic and structural efficiency for future transport aircraft. Attention is given to engine component improvement, an energy efficient turbofan engine, advanced turboprops, revolutionary gains in aerodynamic efficiency for aircraft of the late 1990s, laminar flow control, and composite primary aircraft structures.

  17. Assessing the Ability of Instantaneous Aircraft and Sonde Measurements to Characterize Climatological Means and Long-Term Trends in Tropospheric Composition

    NASA Technical Reports Server (NTRS)

    Murray, Lee T.; Fiore, Arlene M.

    2014-01-01

    Over four decades of measurements exist that sample the 3-D composition of reactive trace gases in the troposphere from approximately weekly ozone sondes, instrumentation on civil aircraft, and individual comprehensive aircraft field campaigns. An obstacle to using these data to evaluate coupled chemistry-climate models (CCMs)the models used to project future changes in atmospheric composition and climateis that exact space-time matching between model fields and observations cannot be done, as CCMs generate their own meteorology. Evaluation typically involves averaging over large spatiotemporal regions, which may not reflect a true average due to limited or biased sampling. This averaging approach generally loses information regarding specific processes. Here we aim to identify where discrete sampling may be indicative of long-term mean conditions, using the GEOS-Chem global chemical-transport model (CTM) driven by the MERRA reanalysis to reflect historical meteorology from 2003 to 2012 at 2o by 2.5o resolution. The model has been sampled at the time and location of every ozone sonde profile available from the Would Ozone and Ultraviolet Radiation Data Centre (WOUDC), along the flight tracks of the IAGOSMOZAICCARABIC civil aircraft campaigns, as well as those from over 20 individual field campaigns performed by NASA, NOAA, DOE, NSF, NERC (UK), and DLR (Germany) during the simulation period. Focusing on ozone, carbon monoxide and reactive nitrogen species, we assess where aggregates of the in situ data are representative of the decadal mean vertical, spatial and temporal distributions that would be appropriate for evaluating CCMs. Next, we identically sample a series of parallel sensitivity simulations in which individual emission sources (e.g., lightning, biogenic VOCs, wildfires, US anthropogenic) have been removed one by one, to assess where and when the aggregated observations may offer constraints on these processes within CCMs. Lastly, we show results of an

  18. Energy absorption capability of foam-based composite materials and their applications as seat cushions in aircraft crashworthiness

    NASA Astrophysics Data System (ADS)

    Kh. Beheshti, Hamid

    This study is focusing on the application of foam materials in aviation. These materials are being used for acoustic purposes, as padding in the finished interior panels of the aircraft, and as seat cushions. Foams are mostly used in seating applications. Since seat cushion is directly interacting with the body of occupant, it has to be ergonomically comfortable beside of absorbing the energy during the impact. All the seats and seat cushions have to pass regulations defined by Federal Aviation Administration (FAA). In fact, all airplane companies are required to certify the subcomponents of aircrafts before installing them on the main structure, fuselage. Current Federal Aviation Administration Regulations require a dynamic sled test of the entire seat system for certifying the seat cushions. This dynamic testing is required also for replacing the deteriorated cushions with new cushions. This involves a costly and time-consuming certification process. AGATE group has suggested a procedure based on quasi-static testing in order to certify new seat cushions without conducting full-scale dynamic sled testing. AGATE subcomponent methodology involves static tests of the energy-absorbing foam cushions and design validation by conducting a full-scale dynamic seat test. Microscopic and macroscopic studies are necessary to provide a complete understanding about performance of foams during the crash. Much investigation has been done by different sources to obtain the reliable modeling in terms of demonstration of mechanical behavior of foams. However, rate sensitivity of foams needs more attention. A mathematical hybrid dynamic model for the cushion underneath of the human body will be taken into consideration in this research. Analytical and finite element codes such as MADYMO and LS-DYNA codes have the potential to greatly speed up the crashworthy design process, to help certify seats and aircraft to dynamic crash loads, to predict seat and occupant response to impact

  19. Structural Framework for Flight: NASA's Role in Development of Advanced Composite Materials for Aircraft and Space Structures

    NASA Technical Reports Server (NTRS)

    Tenney, Darrel R.; Davis, John G., Jr.; Johnston, Norman J.; Pipes, R. Byron; McGuire, Jack F.

    2011-01-01

    This serves as a source of collated information on Composite Research over the past four decades at NASA Langley Research Center, and is a key reference for readers wishing to grasp the underlying principles and challenges associated with developing and applying advanced composite materials to new aerospace vehicle concepts. Second, it identifies the major obstacles encountered in developing and applying composites on advanced flight vehicles, as well as lessons learned in overcoming these obstacles. Third, it points out current barriers and challenges to further application of composites on future vehicles. This is extremely valuable for steering research in the future, when new breakthroughs in materials or processing science may eliminate/minimize some of the barriers that have traditionally blocked the expanded application of composite to new structural or revolutionary vehicle concepts. Finally, a review of past work and identification of future challenges will hopefully inspire new research opportunities and development of revolutionary materials and structural concepts to revolutionize future flight vehicles.

  20. Aircraft surface coatings

    NASA Technical Reports Server (NTRS)

    1982-01-01

    Liquid, spray on elastomeric polyurethanes are selected and investigated as best candidates for aircraft external protective coatings. Flight tests are conducted to measure drag effects of these coatings compared to paints and a bare metal surface. The durability of two elastometric polyurethanes are assessed in airline flight service evaluations. Laboratory tests are performed to determine corrosion protection properties, compatibility with aircraft thermal anti-icing systems, the effect of coating thickness on erosion durability, and the erosion characteristics of composite leading edges-bare and coated. A cost and benefits assessment is made to determine the economic value of various coating configurations to the airlines.

  1. Ultrasonic Inspection Of Thick Sections

    NASA Technical Reports Server (NTRS)

    Friant, C. L.; Djordjevic, B. B.; O'Keefe, C. V.; Ferrell, W.; Klutz, T.

    1993-01-01

    Ultrasonics used to inspect large, relatively thick vessels for hidden defects. Report based on experiments in through-the-thickness transmission of ultrasonic waves in both steel and filament-wound composite cases of solid-fuel rocket motors.

  2. Structural FEM analysis of the strut-to-fuselage joint of a two-seat composite aircraft

    SciTech Connect

    Vargas-Rojas, Erik Camarena-Arellano, Diego Hernández-Moreno, Hilario

    2014-05-15

    An analysis of a strut-to-fuselage joint is realized in order to evaluate the zones with a high probability of failure by means of a safety factor. The whole section is analyzed using the Finite Element Method (FEM) so as to estimate static resistance behavior, therefore it is necessary a numerical mock-up of the section, the mechanical properties of the Carbon-Epoxy (C-Ep) material, and to evaluate the applied loads. Results of the analysis show that the zones with higher probability of failure are found around the wing strut and the fuselage joint, with a safety factor lower than expected in comparison with the average safety factor used on aircrafts built mostly with metals.

  3. An investigation into the use of surface waves for the real-time inspection of polymer composites during fabrication

    NASA Astrophysics Data System (ADS)

    Linstrom, Elizabeth Jane

    A new approach to the nondestructive evaluation of polymer matrix/graphite fiber composites is presented. This technique permits the determination of the top ply bond strength of a laminate based on the results of ultrasonic testing. This technique is designed to be used for the real-time, nondestructive evaluation of composites during tape laying. By separately bonding the top ply of thermoset and thermoplastic polymer composite laminates, a poor ply bond was achieved solely at the interface of the top ply and the rest of the laminate. Using angled incidence, a 5 MHz, 4 musecond ultrasonic pulse was induced into the composite samples. This created waves traveling along the surface of the composite samples that were picked up by a receiving transducer. The received signal was cross-correlated with an artificially constructed replica of the input signal. The maximum amplitude of the cross-correlated signal was recorded. The cross-correlated signal was then converted to the frequency spectra using a fast Fourier transform. The maximum amplitude of the frequency spectra was then recorded. These measurements were repeated at 18 to 30 different locations on each composite sample. The resulting collection of maximum amplitudes of cross-correlated signals and frequency spectra were fit to two parameter Weibull distributions. The composite samples were destructively evaluated using a flat-wise tensile test. The B-basis values of the ultrasonic data Weibull distributions were compared to the B-basis values of the Weibull distribution of the strength data. A good correlation was found.

  4. Thermographic Inspection of Aerospace Tankage

    NASA Technical Reports Server (NTRS)

    Bouvier, Carl; Russell, Samuel; Walker, James; Wilkerson, Chuck

    2003-01-01

    Thermography has been shown to be the ideal technical and economic inspection method for two applications - post-machining evaluations and for field inspections of damage and repair. For most manufacturing applications ultrasonic inspections are already available and established. There is no question about the detectability or cost when inspecting hardware out of the autoclave. But when the part is too large to bring to the scanning inspection system or you do not want to remove the hardware from its current setup then a more portable or field applicable inspection is required. This paper will describe two applications of thermography on composite inspections. The NASA NDE Team and Lockheed Martin conducted the work at NASA s George C. Marshall Space Flight Center (MSFC). The first application was inspecting machined hardware. The technique and example data will be presented along with the advantages of thermography. Examples of drilling holes and trimming the edges will be discussed. The second application will be the evaluation of damage in a composite part and the subsequent repair of the region will be presented. The technique, data, and benefits of this application will also be presented along with the follow-up inspection of the post- repaired hardware.

  5. SHM system using rectangular versus circular piezoceramic for the inspection within the bond of a composite bonded joint

    NASA Astrophysics Data System (ADS)

    Quaegebeur, Nicolas; Micheau, Philippe; Masson, Patrice; Castaings, Michel

    2012-04-01

    A bonded joint between an aluminum plate and CFRP plate (7 plies) is considered using a titanium spar. The bonding is ensured by double sided adhesive that is prone to degradation with aging structures. The problem is to detect the disbond occurring at the CFRP plate/titanium spar interface using guided waves generated by piezoceramic transducers (PZT) bonded on the CFRP plate. The objective of the present work is to optimize the SHM configuration (PZT location, Lamb wave mode, size and shape of the PZT) for pitch and catch measurements within the bond. 1D, 2D and 3D numerical simulations of the instrumented structure were performed to optimize the SHM configuration. It appears that the rectangular shape can ensure a plane wave front within the bond, since the circular shape generates complex wave fronts. For experimental investigation, coupon structure was manufactured with synthetic damages inserted using two hemispherical Teflon tapes between adhesive and titanium spar. The structure was instrumented for inspection within the bond by using rectangular PZT. Experimental validation of propagation characteristics and damage sensitivity are performed using LDV measurement within the bond line. Damage detectability using rectangular piezoceramics in pitch-catch configuration within the bond is validated.

  6. Laser-based ultrasonic inspection with a fiber-coupled scanning Cassegrain system.

    PubMed

    McKie, Andrew D W; Addison, Robert C

    2002-12-01

    State-of-the-art integrally stiffened composite materials, manufactured for use in the next generation of commercial and military aircraft, are increasingly being used for structural components such as wings and fuselages. However, the complexity of the manufacturing processes can produce small variations in the shape of integrally stiffened composite structures. Thus, a priori knowledge of the nominal part shape often does not provide sufficient accuracy to allow an automated conventional ultrasonic inspection. In contrast, automated inspections of integrally stiffened structures can be performed using laser-based ultrasound techniques since a priori knowledge of the nominal part shape is adequate to scan the laser beams over the structure. This paper addresses the issues associated with the extension of laser-based ultrasonics to inspections in remote and limited access areas, and describes the implementation of a fiber-based remote and limited access LBU inspection system based upon a Cassegrain scanning and optical collection system. The ability to quickly and directly manipulate flexible low mass optical fibers equipped with specialized endoscopic scanning optics make fiber systems an attractive method for the development of limited and remote access inspection systems. The Cassegrain optical system is described in detail and both numerical and experimental validation of the system operational characteristics are presented. PMID:12441180

  7. Stress Corrosion Crack Detection on HU-25 Guardian Aircraft

    SciTech Connect

    Blackmon, R.; Huffman, J.; Mello, C.W.; Moore, D.G.; Walkington, P.D.

    1999-02-17

    Several ultrasonic inspection methods were developed at the Federal Aviation Administration's Airworthiness Assurance NDI Validation Center (AANC) to easily and rapidly detect hidden stress corrosion cracks in all vertical windshield posts on the US Coast Guard (USCG) HU-25 Guardian aircraft. The inspection procedure locates cracks as small as 2.0 millimeters emanating from internal fastener holes and determines their length. A test procedure was developed and a baseline assessment of the USCG fleet was conducted. Inspection results on twenty-five aircraft revealed a good correlation with results made during subsequent structural disassembly and visual inspection.

  8. DOD Recovery personnel and NASA technicians inspect Friendship 7 spacecraft

    NASA Technical Reports Server (NTRS)

    1964-01-01

    Department of Defense Recovery personnel and spacecraft technicians from NASA adn McDonnell Aircraft Corp., inspect Astronaut John Glenn's Mercury spacecraft, Friendship 7, following its return to Cape Canaveral after recovery in the Atlantic Ocean.

  9. Effects of compositional changes on the performance of a thermal barrier coating system. [for aircraft gas turbine engines

    NASA Technical Reports Server (NTRS)

    Stecura, S.

    1979-01-01

    Systems consisting of Ni-base bond coatings containing about 16Cr, 6Al, and from 0.15 to 1.08Y (all in wt %) and zirconium oxide layers containing from 4.0 to 24.4Y2O3 were evaluated for suitability as thermal barrier systems for advanced aircraft gas turbine engine components. The evaluations were performed in a cyclic furnace between 990 and 280 C as well as between 1095 and 280 C on solid specimens; in a natural gas-oxygen torch rig between about 1200 and 100 C on solid specimens and up to 1580 C surface temperatures on air-cooled blades; and in a Mach 1.0 burner rig up to 1570 C surface temperatures on air-cooled blades. The data indicate that the best systems consist of combinations involving the Ni-16.4Cr-5.1Al-0.15Y and Ni-17.0Cr-5.4Al-0.35Y bond coatings and the 6.2Y2O3- and 7.9Y2O3- (all in wt %) stabilized zirconium oxide layers.

  10. Advanced manufacturing development of a composite empennage component for L-1011 aircraft. Phase 4: Full scale ground test

    NASA Technical Reports Server (NTRS)

    Jackson, A. C.; Dorwald, F.

    1982-01-01

    The ground tests conducted on the advanced composite vertical fin (ACVF) program are described. The design and fabrication of the test fixture and the transition structure, static test of Ground Test Article (GTA) No. 1, rework of GTA No. 2, and static, damage tolerance, fail-safe and residual strength tests of GTA No. 2 are described.

  11. Nondestructive Evaluation of Aircraft and Spacecraft Wiring

    NASA Technical Reports Server (NTRS)

    White, John E.; Tucholski, Edward J.; Green, Robert E., Jr.

    2004-01-01

    Spacecraft, and especially aircraft, often fry well past their original design lives and, therefore, the need to develop nondestructive evaluation procedures for inspection of vital structures in these craft is extremely important. One of the more recent problems is the degradation of wiring and wiring insulation. The present paper describes several nondestructive characterization methods which afford the possibility to detect wiring and insulation degradation in-situ prior to major problems with the safety of aircraft and spacecraft.

  12. Composites

    NASA Astrophysics Data System (ADS)

    Taylor, John G.

    The Composites market is arguably the most challenging and profitable market for phenolic resins aside from electronics. The variety of products and processes encountered creates the challenges, and the demand for high performance in critical operations brings value. Phenolic composite materials are rendered into a wide range of components to supply a diverse and fragmented commercial base that includes customers in aerospace (Space Shuttle), aircraft (interiors and brakes), mass transit (interiors), defense (blast protection), marine, mine ducting, off-shore (ducts and grating) and infrastructure (architectural) to name a few. For example, phenolic resin is a critical adhesive in the manufacture of honeycomb sandwich panels. Various solvent and water based resins are described along with resin characteristics and the role of metal ions for enhanced thermal stability of the resin used to coat the honeycomb. Featured new developments include pultrusion of phenolic grating, success in RTM/VARTM fabricated parts, new ballistic developments for military vehicles and high char yield carbon-carbon composites along with many others. Additionally, global regional market resin volumes and sales are presented and compared with other thermosetting resin systems.

  13. Space shuttle recommendations based on aircraft maintenance experience

    NASA Technical Reports Server (NTRS)

    Spears, J. M.; Fox, C. L.

    1972-01-01

    Space shuttle design recommendations based on aircraft maintenance experience are developed. The recommendations are specifically applied to the landing gear system, nondestructive inspection techniques, hydraulic system design, materials and processes, and program support.

  14. Pathfinder Aircraft in Flight

    NASA Technical Reports Server (NTRS)

    1995-01-01

    The Pathfinder research aircraft's wing structure was clearly defined as it soared under a clear blue sky during a test flight July 27, 1995, from Dryden Flight Research Center, Edwards, California. The center section and outer wing panels of the aircraft had ribs constructed of thin plastic foam, while the ribs in the inner wing panels are fabricated from lightweight composite material. Developed by AeroVironment, Inc., the Pathfinder was one of several unmanned aircraft being evaluated under NASA's Environmental Research Aircraft and Sensor Technology (ERAST) program. Pathfinder was a lightweight, solar-powered, remotely piloted flying wing aircraft used to demonstrate the use of solar power for long- duration, high-altitude flight. Its name denotes its mission as the 'Pathfinder' or first in a series of solar-powered aircraft that will be able to remain airborne for weeks or months on scientific sampling and imaging missions. Solar arrays covered most of the upper wing surface of the Pathfinder aircraft. These arrays provided up to 8,000 watts of power at high noon on a clear summer day. That power fed the aircraft's six electric motors as well as its avionics, communications, and other electrical systems. Pathfinder also had a backup battery system that could provide power for two to five hours, allowing for limited-duration flight after dark. Pathfinder flew at airspeeds of only 15 to 20 mph. Pitch control was maintained by using tiny elevators on the trailing edge of the wing while turns and yaw control were accomplished by slowing down or speeding up the motors on the outboard sections of the wing. On September 11, 1995, Pathfinder set a new altitude record for solar- powered aircraft of 50,567 feet above Edwards Air Force Base, California, on a 12-hour flight. On July 7, 1997, it set another, unofficial record of 71,500 feet at the Pacific Missile Range Facility, Kauai, Hawaii. In 1998, Pathfinder was modified into the longer-winged Pathfinder Plus

  15. Pathfinder aircraft in flight

    NASA Technical Reports Server (NTRS)

    1995-01-01

    The Pathfinder research aircraft's wing structure was clearly defined as it soared under a clear blue sky during a test flight July 27, 1995, from Dryden Flight Research Center, Edwards, California. The center section and outer wing panels of the aircraft had ribs constructed of thin plastic foam, while the ribs in the inner wing panels are fabricated from lightweight composite material. Developed by AeroVironment, Inc., the Pathfinder was one of several unmanned aircraft being evaluated under NASA's Environmental Research Aircraft and Sensor Technology (ERAST) program. Pathfinder was a lightweight, solar-powered, remotely piloted flying wing aircraft used to demonstrate the use of solar power for long-duration, high-altitude flight. Its name denotes its mission as the 'Pathfinder' or first in a series of solar-powered aircraft that will be able to remain airborne for weeks or months on scientific sampling and imaging missions. Solar arrays covered most of the upper wing surface of the Pathfinder aircraft. These arrays provided up to 8,000 watts of power at high noon on a clear summer day. That power fed the aircraft's six electric motors as well as its avionics, communications, and other electrical systems. Pathfinder also had a backup battery system that could provide power for two to five hours, allowing for limited-duration flight after dark. Pathfinder flew at airspeeds of only 15 to 20 mph. Pitch control was maintained by using tiny elevators on the trailing edge of the wing while turns and yaw control were accomplished by slowing down or speeding up the motors on the outboard sections of the wing. On September 11, 1995, Pathfinder set a new altitude record for solar-powered aircraft of 50,567 feet above Edwards Air Force Base, California, on a 12-hour flight. On July 7, 1997, it set another, unofficial record of 71,500 feet at the Pacific Missile Range Facility, Kauai, Hawaii. In 1998, Pathfinder was modified into the longer-winged Pathfinder Plus

  16. Advanced manufacturing development of a composite empennage component for L-1011 aircraft. Phase 2: Design and analysis

    NASA Technical Reports Server (NTRS)

    Jackson, A. C.; Crocker, J. F.; Ekvall, J. C.; Eudaily, R. R.; Mosesian, B.; Vancleave, R. R.; Vanhamersveld, J.

    1981-01-01

    The composite fin design consists of two one-piece cocured covers, two one-piece cocured spars and eleven ribs. The lower ribs are truss ribs with graphite/epoxy caps and aluminum truss members. The upper three ribs are a sandwich design with graphite/epoxy face sheets and a syntactic epoxy core. The design achieves a 27% weight saving compared to the metal box. The fastener count has been reduced from over 40,000 to less than 7000. The structural integrity of the composite fin was verified by analysis and test. The static, fail-safe and flutter analyses were completed. An extensive test program has established the material behavior under a range of conditions and critical subcomponents were tested to verify the structural concepts.

  17. Design, ancillary testing, analysis and fabrication data for the advanced composite stabilizer for Boeing 737 aircraft. Volume 1: Technical summary

    NASA Technical Reports Server (NTRS)

    Aniversario, R. B.; Harvey, S. T.; Mccarty, J. E.; Parsons, J. T.; Peterson, D. C.; Pritchett, L. D.; Wilson, D. R.; Wogulis, E. R.

    1983-01-01

    The horizontal stabilizer of the 737 transport was redesigned. Five shipsets were fabricated using composite materials. Weight reduction greater than the 20% goal was achieved. Parts and assemblies were readily produced on production-type tooling. Quality assurance methods were demonstrated. Repair methods were developed and demonstrated. Strength and stiffness analytical methods were substantiated by comparison with test results. Cost data was accumulated in a semiproduction environment. FAA certification was obtained.

  18. Separation of airborne and structureborne noise radiated by plates constructed of conventional and composite materials with applications for prediction of interior noise paths in propeller driven aircraft. Ph.D. Thesis

    NASA Technical Reports Server (NTRS)

    Mcgary, M. C.

    1986-01-01

    The anticipated application of advanced turboprop propulsion systems and use of composite materials in primary structure is expected to increase the interior noise of future aircraft to unacceptability high levels. The absence of technically and economically feasible noise source-path diagnostic tools has been a primer obstacle in the development of efficient noise control treatments for propeller driven aircraft. A new diagnostic method which permits the separation and prediction of the fully coherent airborne and structureborne components of the sound radiated by plates or thin shells has been developed. Analytical and experimental studies of the proposed method were performed on plates constructed of both conventional and composite materials. The results of the study indicate that the proposed method can be applied to a variety of aircraft materials, could be used in flight, and has fewer encumbrances than the other diagnostic tools currently available. The study has also revealed that the noise radiation of vibrating plates in the low frequency regime due to combined airborne and structureborne inputs possesses a strong synergistic nature. The large influence of the interaction between the airborne and structureborne terms has been hitherto ignored by researchers of aircraft interior noise problems.

  19. Ultrasonic Inspection

    NASA Technical Reports Server (NTRS)

    1976-01-01

    Automation Industries Inc. has had more than $2 million in contracts to produce innovative equipment for the Apollo program. When Marshall Space Flight Center sought a fast nondestructive way to inspect butt welds in aluminum alloys for spacecraft, the company developed a reliable ultrasonic device using multiple transducers called "delta manipulators" which detect lack of weld penetration not readily seen in radiograph automation. Industry soon adapted the ultrasonic equipment to a unique rail inspection device that saves countless man hours. Device is contained in self propelled railroad cars produced and operated by the company to check old track welds for deterioration.

  20. 19 CFR 162.5 - Search of arriving vehicles and aircraft.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 19 Customs Duties 2 2010-04-01 2010-04-01 false Search of arriving vehicles and aircraft. 162.5...; DEPARTMENT OF THE TREASURY (CONTINUED) INSPECTION, SEARCH, AND SEIZURE Inspection, Examination, and Search § 162.5 Search of arriving vehicles and aircraft. A customs officer may stop any vehicle and board...

  1. 19 CFR 162.5 - Search of arriving vehicles and aircraft.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 19 Customs Duties 2 2011-04-01 2011-04-01 false Search of arriving vehicles and aircraft. 162.5...; DEPARTMENT OF THE TREASURY (CONTINUED) INSPECTION, SEARCH, AND SEIZURE Inspection, Examination, and Search § 162.5 Search of arriving vehicles and aircraft. A customs officer may stop any vehicle and board...

  2. 19 CFR 162.5 - Search of arriving vehicles and aircraft.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 19 Customs Duties 2 2012-04-01 2012-04-01 false Search of arriving vehicles and aircraft. 162.5...; DEPARTMENT OF THE TREASURY (CONTINUED) INSPECTION, SEARCH, AND SEIZURE Inspection, Examination, and Search § 162.5 Search of arriving vehicles and aircraft. A customs officer may stop any vehicle and board...

  3. 19 CFR 162.5 - Search of arriving vehicles and aircraft.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 19 Customs Duties 2 2013-04-01 2013-04-01 false Search of arriving vehicles and aircraft. 162.5...; DEPARTMENT OF THE TREASURY (CONTINUED) INSPECTION, SEARCH, AND SEIZURE Inspection, Examination, and Search § 162.5 Search of arriving vehicles and aircraft. A customs officer may stop any vehicle and board...

  4. 19 CFR 162.5 - Search of arriving vehicles and aircraft.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 19 Customs Duties 2 2014-04-01 2014-04-01 false Search of arriving vehicles and aircraft. 162.5...; DEPARTMENT OF THE TREASURY (CONTINUED) INSPECTION, SEARCH, AND SEIZURE Inspection, Examination, and Search § 162.5 Search of arriving vehicles and aircraft. A customs officer may stop any vehicle and board...

  5. Effects of boron and glass hybrid epoxy-composites on graphite-fiber release in an aircraft fire

    NASA Technical Reports Server (NTRS)

    Tompkins, S. S.; Brewer, W. D.

    1979-01-01

    Recent studies have shown that the benefits gained by using graphite-epoxy composite structures may not be realized without some risk. The graphite fibers are very good electrical conductors and fibers released into the environment during a fire create a possible hazard to electrical equipment. Several graphite-epoxy hybrids were exposed to a fire and simulated explosion and their graphite fiber retention characteristics were examined. Several low melting-temperature glasses which wet and clump graphite-fibers and a glass/graphite fabric which reduced impact damage were identified as promising hybridizing components to minimize graphite fiber release.

  6. STOL Aircraft

    NASA Technical Reports Server (NTRS)

    1988-01-01

    Michael E. Fisher, President of AeroVisions International, has introduced the Culex light twin engine aircraft which offers economy of operation of a single engine plane, the ability to fly well on one engine, plus the capability of flying from short, unimproved fields of takeoff and landing distances less than 35 feet. Key element of design is an airfoil developed by Langley. Culex was originally intended to be factory built aircraft for special utility markets. However, it is now offered as a build-it-yourself kit plane.

  7. Influence of Jet Fuel Composition on Aircraft Engine Emissions: A Synthesis of Aerosol Emissions Data from the NASA APEX, AAFEX, and ACCESS Missions

    NASA Astrophysics Data System (ADS)

    Moore, R.; Shook, M.; Beyersdorf, A. J.; Corr, C.; Herndon, S. C.; Knighton, W. B.; Miake-Lye, R. C.; Thornhill, K. L., II; Winstead, E.; Yu, Z.; Ziemba, L. D.; Anderson, B. E.

    2015-12-01

    We statistically analyze the impact of jet fuel properties on aerosols emitted by the NASA McDonnell Douglas DC-8 CFM56-2-C1 engines burning fifteen different aviation fuels. Data were collected for this single engine type during four different, comprehensive ground tests conducted over the past decade, which allow us to clearly link changes in aerosol emissions to fuel compositional changes. It is found that the volatile aerosol fraction dominates the number and volume emissions indices (EIs) over all engine powers, which are driven by changes in fuel aromatic and sulfur content. Meanwhile, the naphthalenic content of the fuel determines the magnitude of the non-volatile number and volume EI as well as the black carbon mass EI. Linear regression coefficients are reported for each aerosol EI in terms of these properties, engine fuel flow rate, and ambient temperature, and show that reducing both fuel sulfur content and napththalenes to near-zero levels would result in roughly a ten-fold decrease in aerosol number emitted per kg of fuel burn. This work informs future efforts to model aircraft emissions changes as the aviation fleet gradually begins to transition toward low-aromatic, low-sulfur alternative jet fuels from bio-based or Fischer-Tropsch production pathways.

  8. Infrared thermographic diagnostic aid to aircraft maintenance

    NASA Astrophysics Data System (ADS)

    Delo, Michael; Delo, Steve

    2007-04-01

    Thermographic data can be used as a supplement to aircraft maintenance operations in both back shop and flight line situations. Aircraft systems such as electrical, propulsion, environmental, pitot static and hydraulic/pneumatic fluid, can be inspected using a thermal infrared (IR) imager. Aircraft systems utilize electro-hydraulic, electro-mechanical, and electro-pneumatic mechanisms, which, if accessible, can be diagnosed for faults using infrared technology. Since thermographs are images of heat, rather than light, the measurement principle is based on the fact that any physical object (radiating energy at infrared wavelengths within the IR portion of the electro-magnetic spectrum), can be imaged with infrared imaging equipment. All aircraft systems being tested with infrared are required to be energized for troubleshooting, so that valuable baseline data from fully operational aircraft can be collected, archived and referenced for future comparisons.

  9. Aircraft fatigue failures and tasks of structural reliability analysis

    NASA Astrophysics Data System (ADS)

    Fujiwara, Genkichi

    The aircraft structural inspection pattern and the statistical method of the structural fatigue life prediction are presented. The problems of the aircraft structural life span and the evaluation of fatigue strength are discussed, such as out of plane bending and deformation, and multiple site damage (MSD). The crack data of Boeing 747 section 41 upper deck frame and stringer is listed.

  10. TPS Inspection and Repair

    NASA Technical Reports Server (NTRS)

    Parazynski, Scott

    2012-01-01

    Dr. Scott Parazynski provided a retrospective on the EVA tools and procedures efforts NASA went through in the aftermath of Columbia for the Shuttle Thermal Protection System (TPS) inspection and repair. He describes his role as the lead astronaut on this effort, and covered all of the Neutral Buoyancy Lab (NBL), KC 135 (reduced gravity aircraft), Precision Air Bearing Floor (PABF), vacuum chamber and 1 G testing that was done in order to develop the tools and techniques that were flown. Parazynski also discusses how the EVA community worked together to resolve a huge safety issue, and how his work in the spacesuit was critical to overcoming a design limitation of the Space Shuttle.

  11. Advanced technology and manufacturing practices for machining and inspecting metal matrix composites. Final CRADA report for CRADA number Y-1292-0092

    SciTech Connect

    Fell, H.A.; Shelton, J.E.; LaMance, G.M.; Kennedy, C.R.

    1995-02-26

    Lockheed Martin Energy Systems, Inc. (Energy Systems) and the Lanxide Corporation (Lanxide) negotiated a Cooperative Research and Development Agreement (CRADA) to develop advanced technology and manufacturing practices for machining and inspecting metal matrix composites (MMC). The objective of this CRADA was to develop machining parameters to allow manufacturing of automotive components from MMCs. These parts exhibit a range of shapes and dimensional tolerances and require a large number of machining operations. The common characteristic of the components is the use of the light weight MMC materials to replace heavier materials. This allows smaller and lighter moving parts and supporting structural components thereby increasing fuel mileage. The CRADA was divided into three areas: basic investigation of cutting parameters, establishment of a mock production line for components, and optimization of parameters in the mock facility. This report covers the manufacturing of MMCs and preliminary Phase I testing for silicon carbide having various loading percentages and extensive Phase I testing of cutting parameters on 30% alumina loaded aluminum. On January 26, 1995, a letter from the vice president, technology at Lanxide was issued terminating the CRADA due to changes in business. 9 refs., 18 figs., 3 tabs.

  12. Activities at the FAA aging aircraft NDI validation center

    SciTech Connect

    Shurtleff, W.

    1994-08-01

    Aging Aircraft NDI Validation Center (AANC) was established by the FAA Technical Center (FAATC) at Sandia National Laboratories in August of 1991. The Validation Center supports the inspection portion of the FAA`s National Aging Aircraft Program which was mandated by Congress in the 1988 Aviation Safety Act. The ultimate customers of the AANC include the FAA, airframe and engine manufacturers, airlines, and third party maintenance facilities. One goal of the AANC is to provide independent validation of technologies intended to enhance the structural inspection of aging commuter and transport aircraft. Another goal is to assist in transferring emerging inspection technology from other parts of the FAA`s program to the aircraft industry. The deliverables from both these activities are an assessment of the reliability and cost benefits of an inspection technology as applied to a particular inspection or class of inspections. The validation process consists of a quantitative and systematic assessment of the reliability and cost/benefits on a Nondestructive Inspection (NDI) process. A NDI process is defined as the NDI systems and procedures used for inspections. This includes the NDI operator, inspection environment, and the object being inspected. The phases of the validation process are: 1. Conceptual, 2. Preliminary design, 3. Final design, and 4. Field implementation. The AAANC usually gets involved in the validation process during Phases 2 and 3. The Center supports field trials with a full array of test specimens and established procedures for conducting the trials. Phase 4 reliability includes field trials using independent inspectors either at the Center`s hangar or at outside maintenance facilities. Three activities are summarized below where inspection technology has been validated in the field. These are: (1) eddy current inspection reliability experiment; (2) magneto optic imager validation; and (3) inspection tool improvement.

  13. Advanced manufacturing development of a composite empennage component for L-1011 aircraft. Phase 3: Production readiness verification testing

    NASA Technical Reports Server (NTRS)

    Jackson, A.; Sandifer, J.; Sandorff, P.; Vancleave, R.

    1984-01-01

    Twenty-two specimens of each of two key structural elements of the Advance Composite Vertical Fin (ACVF) were fabricated and tested. One element represented the front spar at the fuselage attachment area and the other element represented the cover at the fuselage joint area. Ten specimens of each element were selected for static testing. The coefficient of variation resulting from the tests was 3.28 percent for the ten cover specimens and 6.11 percent for the ten spar specimens, which compare well with metallic structures. The remaining twelve cover and twelve spar specimens were durability tested in environmental chambers which permitted the temperature and humidity environment to be cycled as well as the applied loads. Results of the durability tests indicated that such components will survive the service environment.

  14. 14 CFR 33.93 - Teardown inspection.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... inspection, analysis, test, or by any combination thereof as found necessary by the FAA, that structural integrity of the engine is maintained; or (c) In lieu of compliance with paragraph (b) of this section, each... Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT...

  15. 49 CFR 175.30 - Inspecting shipments.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 2 2014-10-01 2014-10-01 false Inspecting shipments. 175.30 Section 175.30 Transportation Other Regulations Relating to Transportation PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION HAZARDOUS MATERIALS REGULATIONS CARRIAGE BY AIRCRAFT General Information and Regulations § 175.30...

  16. 49 CFR 175.30 - Inspecting shipments.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 2 2011-10-01 2011-10-01 false Inspecting shipments. 175.30 Section 175.30 Transportation Other Regulations Relating to Transportation PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION HAZARDOUS MATERIALS REGULATIONS CARRIAGE BY AIRCRAFT General Information and Regulations § 175.30...

  17. 14 CFR 21.615 - FAA inspection.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false FAA inspection. 21.615 Section 21.615 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT CERTIFICATION... request of the Administrator, each manufacturer of an article under a TSO authorization shall allow...

  18. Aircraft cybernetics

    NASA Technical Reports Server (NTRS)

    1977-01-01

    The use of computers for aircraft control, flight simulation, and inertial navigation is explored. The man-machine relation problem in aviation is addressed. Simple and self-adapting autopilots are described and the assets and liabilities of digital navigation techniques are assessed.

  19. Review of progress in magnetic particle inspection

    NASA Astrophysics Data System (ADS)

    Eisenmann, David J.; Enyart, Darrel; Lo, Chester; Brasche, Lisa

    2014-02-01

    Magnetic particle inspection (MPI) has been widely utilized for decades, and sees considerable use in the aerospace industry with a majority of the steel parts being inspected with MPI at some point in the lifecycle. Typical aircraft locations inspected are landing gear, engine components, attachment hardware, and doors. In spite of its numerous applications the method remains poorly understood, and there are many aspects of that method which would benefit from in-depth study. This shortcoming is due to the fact that MPI combines the complicated nature of electromagnetics, metallurgical material effects, fluid-particle motion dynamics, and physiological human factors into a single inspection. To promote understanding of the intricate method issues that affect sensitivity, or to assist with the revision of industry specifications and standards, research studies will be prioritized through the guidance of a panel of industry experts, using an approach which has worked successfully in the past to guide fluorescent penetrant inspection (FPI) research efforts.

  20. Laser-Scan Ultrasonic/Thermographic Inspection System

    NASA Technical Reports Server (NTRS)

    Bar-Cohen, Yoseph; Marzwell, Neville; Chung, Tom; Carman, Greg

    1996-01-01

    Laser ultrasonic/thermographic inspection system is conceptual instrument used in nondestructive inspection of large areas of structures for subsurface defects. For example, operated in field to examine aircraft and pressure vessels for hidden cracks. System would not require contact with inspected structure or use of ultrasonic-coupling medium. Instrument obtains data in ultrasonic and thermographic C-scans over structural surfaces with contours characterized by surface normal vectors varying by angles as large as 45 degrees.

  1. Relation between repeatability and speed of robot-based systems for composite aircraft production through multilateration sensor system

    NASA Astrophysics Data System (ADS)

    Bock, M.; Perner, M.; Krombholz, C.; Beykirch, B.

    2015-03-01

    Fiber composites are becoming increasingly important in different fields of lightweight application. To guarantee the estimated demand of components made of carbon fiber reinforced plastics the use of industrial robots is suggested in production. High velocity of the layup process is addressed to significantly increase the production rate. Today, the layup of the fiber material is performed by gantry systems. They are heavy weight, slow and the variety of possible part shapes is limited. Articulated robots offer a huge operational area in relation to their construction size. Moreover, they are flexible enough to layup fiber material into different shaped molds. Thus, standard articulated robots are less accurate and more susceptible to vibration than gantry systems. Therefore, this paper illustrates an approach to classify volumetric errors to obtain a relation between the achievable speed in production and precision. The prediction of a precision at a defined speed is the result. Based on the measurement results the repeatability of the robotic unit within the workspace is calculated and presented. At the minimum speed that is applicable in production the repeatability is less than 30 mm. Subsequently, an online strategy for path error compensation is presented. The approach uses a multilateration system that consists of four laser tracer units and measures the current absolute position of a reflector mounted at the end-effector of the robot. By calculating the deviation between the planned and the actual position a compensated motion is applied. The paper concludes with a discussion for further investigations.

  2. 7 CFR 305.9 - Aerosol spray for aircraft treatment schedule.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 5 2010-01-01 2010-01-01 false Aerosol spray for aircraft treatment schedule. 305.9... INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE PHYTOSANITARY TREATMENTS Chemical Treatments § 305.9 Aerosol spray for aircraft treatment schedule. (a) Military aircraft. Aerosol disinfection of U.S....

  3. Optimisation of the geometry of the drill bit and process parameters for cutting hybrid composite/metal structures in new aircrafts

    NASA Astrophysics Data System (ADS)

    Isbilir, Ozden

    Owing to their desirable strength-to-weight characteristics, carbon fibre reinforced polymer composites have been favourite materials for structural applications in different industries such as aerospace, transport, sports and energy. They provide a weight reduction in whole structure and consequently decrease fuel consumption. The use of lightweight materials such as titanium and its alloys in modern aircrafts has also increased significantly in the last couple of decades. Titanium and its alloys offer high strength/weight ratio, high compressive and tensile strength at high temperatures, low density, excellent corrosion resistance, exceptional erosion resistance, superior fatigue resistance and relatively low modulus of elasticity. Although composite/metal hybrid structures are increasingly used in airframes nowadays, number of studies regarding drilling of composite/metal stacks is very limited. During drilling of multilayer materials different problems may arise due to very different attributes of these materials. Machining conditions of drilling such structures play an important role on tool wear, quality of holes and cost of machining.. The research work in this thesis is aimed to investigate drilling of CFRP/Ti6Al4V hybrid structure and to optimize process parameters and drill geometry. The research work consist complete experimental study including drilling tests, in-situ and post measurements and related analysis; and finite element analysis including fully 3-D finite element models. The experimental investigations focused on drilling outputs such as thrust force, torque, delamination, burr formation, surface roughness and tool wear. An algorithm was developed to analyse drilling induced delamination quantitatively based on the images. In the numerical analysis, novel 3-D finite element models of drilling of CFRP, Ti6Al4V and CFRP/Ti6Al4V hybrid structure were developed with the use of 3-D complex drill geometries. A user defined subroutine was developed

  4. Pilot factors guidelines for the operational inspection of navigation systems

    NASA Technical Reports Server (NTRS)

    Sadler, J. F.; Boucek, G. P.

    1988-01-01

    A computerized human engineered inspection technique is developed for use by FAA inspectors in evaluating the pilot factors aspects of aircraft navigation systems. The short title for this project is Nav Handbook. A menu-driven checklist, computer program and data base (Human Factors Design Criteria) were developed and merged to form a self-contained, portable, human factors inspection checklist tool for use in a laboratory or field setting. The automated checklist is tailored for general aviation navigation systems and can be expanded for use with other aircraft systems, transports or military aircraft. The Nav Handbook inspection concept was demonstrated using a lap-top computer and an Omega/VLF CDU. The program generates standardized inspection reports. Automated checklists for LORAN/C and R NAV were also developed. A Nav Handbook User's Guide is included.

  5. [The modelling of the composition of the thermal oxidative breakdown products of aviation oils determined in the cabin air of aircraft].

    PubMed

    Belkin, B I; Filippov, A F; Kozlovskaia, N N

    1994-01-01

    The authors suggested a method to obtain a mixture of chemicals from splitting thermo-oxidation of aviation oil. The qualitative and quantitative aspects of the mixture correspond to the concentration of the chemicals in the air of aircraft cabins. The possibility to obtain such mixtures helps to assess in hygienic laboratory conditions a level of air pollution with aviation oil in aircraft cabins. PMID:7834229

  6. The NASA Aircraft Energy Efficiency Program

    NASA Technical Reports Server (NTRS)

    Klineberg, J. M.

    1978-01-01

    The objective of the NASA Aircraft Energy Efficiency Program is to accelerate the development of advanced technology for more energy-efficient subsonic transport aircraft. This program will have application to current transport derivatives in the early 1980s and to all-new aircraft of the late 1980s and early 1990s. Six major technology projects were defined that could result in fuel savings in commercial aircraft: (1) Engine Component Improvement, (2) Energy Efficient Engine, (3) Advanced Turboprops, (4) Energy Efficiency Transport (aerodynamically speaking), (5) Laminar Flow Control, and (6) Composite Primary Structures.

  7. The effects of aircraft on climate and pollution. Part I: Numerical methods for treating the subgrid evolution of discrete size- and composition-resolved contrails from all commercial flights worldwide

    NASA Astrophysics Data System (ADS)

    Jacobson, M. Z.; Wilkerson, J. T.; Naiman, A. D.; Lele, S. K.

    2011-06-01

    This paper provides and evaluates mass conservative, positive-definite, unconditionally-stable, and non-iterative numerical techniques for simulating the evolution of discrete, size- and composition-resolved aerosol and contrail particles in individual aircraft exhaust plumes in a global or regional 3-D atmospheric model and coupling the subgrid exhaust plume information to the grid scale. Such treatment represents a new method of simulating the effects of aircraft on climate, contrails, and atmospheric composition. Microphysical processes solved within each plume include size-resolved coagulation among and between aerosol and contrail particles and their inclusions, aerosol-to-hydrometeor particle ice and liquid nucleation, deposition/sublimation, and condensation/evaporation. Each plume has its own emission and supersaturation, and the spreading and shearing of each plume's cross-section are calculated as a function of time. Aerosol- and contrail-particle core compositions are tracked for each size and affect optical properties in each plume. When line contrails sublimate/evaporate, their size- and composition-resolved aerosol cores and water vapor are added to the grid scale where they affect large-scale clouds. Algorithm properties are analyzed, and the end-result model is evaluated against in situ and satellite data.

  8. Overview of composite projects at the FAA Airworthiness Assurance Validation Center

    SciTech Connect

    Shurtleff, W.W.; Roach, D.P.; Valley, M.T.

    1997-03-01

    The Airworthiness Assurance NDI Validation Center (AANC) was established by the Federal Aviation Administration (FAA) William J. Hughes Technical Center at Sandia National Laboratories in 1991 to support nondestructive inspection (NDI) technology development and assessment. The evaluations are done using a variety of characterized test specimens and test beds including entire transport and commuter aircraft. Although the initial work at the Center concentrated on metallic structure, the FAA has more recently expanded the AANC`s charter to include projects directed at composite repair and inspection. The three projects briefly described in this paper are: (1) the validation and technology transfer of a thermographic techniques for composite inspection, (2) the development of generic composite laminate and honeycomb calibration reference standards, and (3) the certification of the use of boron epoxy doubler on a Lockheed L-1011.

  9. Development of damage monitoring system for aircraft structure using a PZT actuator/FBG sensor hybrid system

    NASA Astrophysics Data System (ADS)

    Ogisu, Toshimichi; Shimanuki, Masakazu; Kiyoshima, Satoshi; Okabe, Yoji; Takeda, Nobuo

    2004-07-01

    This paper presents a part of the research results on a damage monitoring system using PZT actuators/FBG sensors for advanced composite material structures of new-generation aircrafts. To achieve weight reduction of the aircraft structure, these advanced composite materials have gradually been employed for the primary structure. It is expected that when these materials are extensively employed, an efficient bonded structure such as a hat-shaped stringer will be utilized for the aircraft structure. However, these bonded structures have critical problems such as debonding and delamination at the interfaces of the laminate. Further, a single-step molding process of the structure elements is necessary in order to ensure low cost and thus affordability. However, this low-cost process results in an increase in the non-destructive inspection (NDI) cost. Therefore, an innovative damage monitoring system is required for structural health management. In the present study, the authors have developed a hybrid sensor system that can detect the elastic waves launched from the piezo transducer (PZT) actuator using a high-speed and high-accuracy fiber Bragg grating (FBG) sensor to resolve the issues mentioned above. In this study, the conceptual design of an aircraft that can employ this damage monitoring system was carried out. Subsequently, the application area was selected based on cases of certain kinds of damage. Further, the validity of the damage monitoring system for the verification of the structural integrity of the aircraft was discussed. Next, in order to verify the elastic wave detectability of the FBG sensor, it was confirmed that an elastic wave of 300 kHz is detectable at a distance of 5 cm between the PZT actuator and FBG sensor using an aluminum sheet and CFRP cross-ply laminate and also by considering the relationship between sensor length and sensitivity. Through the present research results, the possibility of applying the damage monitoring system to the

  10. Sensors for aircraft corrosion -- Review and future developments

    SciTech Connect

    Tullmin, M.A.A.; Roberge, P.R.; Little, M.A.

    1997-12-01

    In the Canadian Forces, as for other aircraft operators, the need has arise to utilize new tools for managing corrosion problems more cost effectively. In this context, the role of aircraft corrosion sensors and the current state of this technological field was reviewed, together with identifying future development work. Three separate aircraft corrosion surveillance application areas have been defined, as a basis for evaluating the strengths and weaknesses of various corrosion sensor technologies. At present, the biggest technical shortcomings exist for the important task of reducing unnecessary inspections. The development of smart sensors integrated into the aircraft structure is recommended for this requirement.

  11. Use of nondestructive inspection and fiber optic sensing for damage characterization in carbon fiber fuselage structure

    NASA Astrophysics Data System (ADS)

    Neidigk, Stephen; Le, Jacqui; Roach, Dennis; Duvall, Randy; Rice, Tom

    2014-04-01

    To investigate a variety of nondestructive inspection technologies and assess impact damage characteristics in carbon fiber aircraft structure, the FAA Airworthiness Assurance Center, operated by Sandia National Labs, fabricated and impact tested two full-scale composite fuselage sections. The panels are representative of structure seen on advanced composite transport category aircraft and measured approximately 56"x76". The structural components consisted of a 16 ply skin, co-cured hat-section stringers, fastened shear ties and frames. The material used to fabricate the panels was T800 unidirectional pre-preg (BMS 8-276) and was processed in an autoclave. Simulated hail impact testing was conducted on the panels using a high velocity gas gun with 2.4" diameter ice balls in collaboration with the University of California San Diego (UCSD). Damage was mapped onto the surface of the panels using conventional, hand deployed ultrasonic inspection techniques, as well as more advanced ultrasonic and resonance scanning techniques. In addition to the simulated hail impact testing performed on the panels, 2" diameter steel tip impacts were used to produce representative impact damage which can occur during ground maintenance operations. The extent of impact damage ranges from less than 1 in2 to 55 in2 of interply delamination in the 16 ply skin. Substructure damage on the panels includes shear tie cracking and stringer flange disbonding. It was demonstrated that the fiber optic distributed strain sensing system is capable of detecting impact damage when bonded to the backside of the fuselage.

  12. Carbon fiber counting. [aircraft structures

    NASA Technical Reports Server (NTRS)

    Pride, R. A.

    1980-01-01

    A method was developed for characterizing the number and lengths of carbon fibers accidentally released by the burning of composite portions of civil aircraft structure in a jet fuel fire after an accident. Representative samplings of carbon fibers collected on transparent sticky film were counted from photographic enlargements with a computer aided technique which also provided fiber lengths.

  13. Advanced technology for future regional transport aircraft

    NASA Technical Reports Server (NTRS)

    Williams, L. J.

    1982-01-01

    In connection with a request for a report coming from a U.S. Senate committee, NASA formed a Small Transport Aircraft Technology (STAT) team in 1978. STAT was to obtain information concerning the technical improvements in commuter aircraft that would likely increase their public acceptance. Another area of study was related to questions regarding the help which could be provided by NASA's aeronautical research and development program to commuter aircraft manufacturers with respect to the solution of technical problems. Attention is given to commuter airline growth, current commuter/region aircraft and new aircraft in development, prospects for advanced technology commuter/regional transports, and potential benefits of advanced technology. A list is provided of a number of particular advances appropriate to small transport aircraft, taking into account small gas turbine engine component technology, propeller technology, three-dimensional wing-design technology, airframe aerodynamics/propulsion integration, and composite structure materials.

  14. Fiber optics for advanced aircraft

    NASA Technical Reports Server (NTRS)

    Baumbick, Robert J.

    1988-01-01

    The increased use of composites makes the digital control more susceptible to electromagnetic effects. In order to provide the protection to the digital control additional shielding will be required as well as protective circuitry for the electronics. This results in increased weight and reduced reliability. The advantages that fiber optic technology provides for advanced aircraft applications is recognized. The use of optical signals to carry information between the aircraft and the control module provides immunity from contamination by electromagnetic sources as well as other important benefits such as reduced weight and volume resulting from the elimination of the shielding and the replacement of metal conductors with low weight glass fibers. In 1975 NASA began work to develop passive optical sensors for use with fiber optics in aircraft control systems. The problem now is to choose the best optical sensor concepts and evaluate them for use. In 1985 NASA and DOD entered into a joint program, Fiber Optic Control System Integration (FOCSI), to look at optical technology specifically for use in advanced aircraft systems. The results of this program are discussed. The conclusion of the study indicated that the use of fiber optic technology in advanced aircraft systems is feasible and desirable. The study pointed to a lack of available sensors from vendors capable of operating in the adverse environments of advanced aircraft.

  15. Fiber optics for advanced aircraft

    NASA Technical Reports Server (NTRS)

    Baumbick, Robert J.

    1989-01-01

    The increased use of composites makes the digital control more susceptible to electromagnetic effects. In order to provide the protection to the digital control additional shielding will be required as well as protective circuitry for the electronics. This results in increased weight and reduced reliability. The advantages that fiber optic technology provides for advanced aircraft applications is recognized. The use of optical signals to carry information between the aircraft and the control module provides immunity from contamination by electromagnetic sources as well as other important benefits such as reduced weight and volume resulting from the elimination of the shielding and the replacement of metal conductors with low weight glass fibers. In 1975 NASA began work to develop passive optical sensors for use with fiber optics in aircraft control systems. The problem now is to choose the best optical sensor concepts and evaluate them for use. In 1985 NASA and DOD entered into a joint program, Fiber Optic Control System Integration (FOCSI), to look at optical technology specifically for use in advanced aircraft systems. The results of this program are discussed. The conclusion of the study indicated that the use of fiber optic technology in advanced aircraft systems is feasible and desirable. The study pointed to a lack of available sensors from vendors capable of operating in the adverse environments of advanced aircraft.

  16. Educating with Aircraft Models

    ERIC Educational Resources Information Center

    Steele, Hobie

    1976-01-01

    Described is utilization of aircraft models, model aircraft clubs, and model aircraft magazines to promote student interest in aerospace education. The addresses for clubs and magazines are included. (SL)

  17. 75 FR 51953 - Notification and Reporting of Aircraft Accidents or Incidents and Overdue Aircraft, and...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-24

    ... Register (FR), is available for inspection and copying in the NTSB's public reading room, located at 490 L... Aircraft Wreckage, Mail, Cargo, and Records,'' in the Federal Register (73 FR 16826). This NPRM proposed... Authorization (COA). See 72 FR 6689 (Feb. 13, 2007). The FAA COA Guidance Manual 08-01 notes that reports...

  18. Impact of Advanced Propeller Technology on Aircraft/Mission Characteristics of Several General Aviation Aircraft

    NASA Technical Reports Server (NTRS)

    Keiter, I. D.

    1982-01-01

    Studies of several General Aviation aircraft indicated that the application of advanced technologies to General Aviation propellers can reduce fuel consumption in future aircraft by a significant amount. Propeller blade weight reductions achieved through the use of composites, propeller efficiency and noise improvements achieved through the use of advanced concepts and improved propeller analytical design methods result in aircraft with lower operating cost, acquisition cost and gross weight.

  19. Crack detection on HC-130H aircraft using low frequency eddy current

    SciTech Connect

    Moore, D.G.; Mihelic, J.E.; Barnes, J.D.

    1998-02-01

    An eddy current inspection method was developed at the Federal Aviation Administration`s Airworthiness Assurance NDI Validation Center (AANC) to easily and rapidly detect subsurface fatigue cracks in the wheel well fairing on the US Coast Guard (USCG) HC-130H aircraft caused by fatigue. The inspection procedure locates cracks as small as 10.2 millimeters in length at 2.54 mm below the skin surface at raised fastener sites. The test procedure developed baseline three USCG aircraft. Inspection results on the three aircraft reveals good correlation with results made during subsequent structural disassembly.

  20. Structural risk assessment and aircraft fleet maintenance

    NASA Technical Reports Server (NTRS)

    Smith, Herb, Jr.; Saff, C. R.; Christian, Tom F.

    1990-01-01

    In the present analysis, deterministic flaw growth analysis is used to project the failure distributions from inspection data. Inspection data is reported for each critical point in the aircraft. The data will indicate either a crack of a specific size or no crack. The crack length may be either less than, equal to, or greater than critical size for that location. Non-critical length cracks are projected to failure using the crack growth characteristics for that location to find the life when it will be at critical length. Greater-than-critical length cracks are projected back to determine the life at failure, that is, when it was at critical length. The same process is used as in the case of a non-critical crack except that the projection goes the other direction. These points, along with the critical length cracks are used to determine the failure distribution. To be able to use data from different aircraft to build a common failure distribution, a consistent life variable must be used. Aircraft life varies with the severity of the usage; therefore the number of flight hours for a particular aircraft must be modified by its usage factor to obtain a normalized life which can be compared with that from other aircraft.

  1. Rapid Inspection of Aerospace Structures - Is It Autonomous Yet?

    NASA Technical Reports Server (NTRS)

    Bar-Cohen, Yoseph; Backes, Paul; Joffe, Benjamin

    1996-01-01

    The trend to increase the usage of aging aircraft added a great deal of urgency to the ongoing need for low-cost, rapid, simple-to-operate, reliable and efficient NDE methods for detection and characterization of flaws in aircraft structures. In many cases, the problem of inspection is complex due to the limitation of current technology and the need to disassemble aircraft structures and testing them in lab conditions. To overcome these limitations, reliable field inspection tools are being developed for rapid NDE of large and complex-shape structures, that can operate at harsh, hostal and remote conditions with minimum human interface. In recent years, to address the need for rapid inspection in field conditions, numerous portable scanners were developed using NDE methods, including ultrasonics, shearography, thermography. This paper is written with emphasis on ultrasonic NDE scanners, their evolution and the expected direction of growth.

  2. Aircraft Electric Secondary Power

    NASA Technical Reports Server (NTRS)

    1983-01-01

    Technologies resulted to aircraft power systems and aircraft in which all secondary power is supplied electrically are discussed. A high-voltage dc power generating system for fighter aircraft, permanent magnet motors and generators for aircraft, lightweight transformers, and the installation of electric generators on turbine engines are among the topics discussed.

  3. World commercial aircraft accidents

    SciTech Connect

    Kimura, C.Y.

    1993-01-01

    This report is a compilation of all accidents world-wide involving aircraft in commercial service which resulted in the loss of the airframe or one or more fatality, or both. This information has been gathered in order to present a complete inventory of commercial aircraft accidents. Events involving military action, sabotage, terrorist bombings, hijackings, suicides, and industrial ground accidents are included within this list. Included are: accidents involving world commercial jet aircraft, world commercial turboprop aircraft, world commercial pistonprop aircraft with four or more engines and world commercial pistonprop aircraft with two or three engines from 1946 to 1992. Each accident is presented with information in the following categories: date of the accident, airline and its flight numbers, type of flight, type of aircraft, aircraft registration number, construction number/manufacturers serial number, aircraft damage, accident flight phase, accident location, number of fatalities, number of occupants, cause, remarks, or description (brief) of the accident, and finally references used. The sixth chapter presents a summary of the world commercial aircraft accidents by major aircraft class (e.g. jet, turboprop, and pistonprop) and by flight phase. The seventh chapter presents several special studies including a list of world commercial aircraft accidents for all aircraft types with 100 or more fatalities in order of decreasing number of fatalities, a list of collision accidents involving commercial aircrafts, and a list of world commercial aircraft accidents for all aircraft types involving military action, sabotage, terrorist bombings, and hijackings.

  4. Detection and Assessment of Aircraft Corrosion

    SciTech Connect

    Maldonado, R L; Jones, K W

    1993-05-22

    The detection and assessment of existing corrosion, or the onset thereof, in aircraft structures, related systems and components is of major concern to the United States aviation community. In this work several types of ion- and photon-beam analytical techniques were applied to the detection and assessment of corrosion. A method of laboratory classification of surface corrosion, and the identification of a corrosion preventative compound (CPC)applied on skin material removed from aircraft structures was developed. The results of this research will be useful in the development of instrumentation and inspection techniques to detect and assess corrosion. These techniques also will be useful in studying the mechanisms and efficacy of current and future CPCs. Developed instrumentation and inspection techniques have enormous potential for commercial and military application in many areas, including the transportation, nuclear, petroleum, and building sectors.

  5. Inspection and Emotion

    ERIC Educational Resources Information Center

    Perryman, Jane

    2007-01-01

    In this paper I explore the emotional impact of inspection on the staff of a school in the two years between Ofsted inspections. Using data from one school undergoing inspection, I argue that the negative emotional impact of inspection of teachers goes beyond the oft-reported issues of stress and overwork. Teachers experience a loss of power and…

  6. The design of sport and touring aircraft

    NASA Technical Reports Server (NTRS)

    Eppler, R.; Guenther, W.

    1984-01-01

    General considerations concerning the design of a new aircraft are discussed, taking into account the objective to develop an aircraft can satisfy economically a certain spectrum of tasks. Requirements related to the design of sport and touring aircraft included in the past mainly a high cruising speed and short take-off and landing runs. Additional requirements for new aircraft are now low fuel consumption and optimal efficiency. A computer program for the computation of flight performance makes it possible to vary automatically a number of parameters, such as flight altitude, wing area, and wing span. The appropriate design characteristics are to a large extent determined by the selection of the flight altitude. Three different wing profiles are compared. Potential improvements with respect to the performance of the aircraft and its efficiency are related to the use of fiber composites, the employment of better propeller profiles, more efficient engines, and the utilization of suitable instrumentation for optimal flight conduction.

  7. NDE of Damage in Aircraft Flight Control Surfaces

    NASA Astrophysics Data System (ADS)

    Hsu, David K.; Barnard, Daniel J.; Dayal, Vinay

    2007-03-01

    Flight control surfaces on an aircraft, such as ailerons, flaps, spoilers and rudders, are typically adhesively bonded composite or aluminum honeycomb sandwich structures. These components can suffer from damage caused by hail stone, runway debris, or dropped tools during maintenance. On composites, low velocity impact damages can escape visual inspection, whereas on aluminum honeycomb sandwich, budding failure of the honeycomb core may or may not be accompanied by a disbond. This paper reports a study of the damage morphology in such structures and the NDE methods for detecting and characterizing them. Impact damages or overload failures in composite sandwiches with Nomex or fiberglass core tend to be a fracture or crinkle or the honeycomb cell wall located a distance below the facesheet-to-core bondline. The damage in aluminum honeycomb is usually a buckling failure, propagating from the top skin downward. The NDE methods used in this work for mapping out these damages were: air-coupled ultrasonic scan, and imaging by computer aided tap tester. Representative results obtained from the field will be shown.

  8. Laser Safety Inspection Criteria

    SciTech Connect

    Barat, K

    2005-06-13

    A responsibility of the Laser Safety Officer (LSO) is to perform laser audits. The American National Standard Z136.1 Safe Use of Lasers references this requirement through several sections. One such reference is Section 1.3.2.8, Safety Features Audits, ''The LSO shall ensure that the safety features of the laser installation facilities and laser equipment are audited periodically to assure proper operation''. The composition, frequency and rigor of that inspection/audit rests in the hands of the LSO. A common practice for institutions is to develop laser audit checklists or survey forms It is common for audit findings from one inspector or inspection to the next to vary even when reviewing the same material. How often has one heard a comment, ''well this area has been inspected several times over the years and no one ever said this or that was a problem before''. A great number of audit items, and therefore findings, are subjective because they are based on the experience and interest of the auditor to particular items on the checklist. Beam block usage, to one set of eyes might be completely adequate, while to another, inadequate. In order to provide consistency, the Laser Safety Office of the National Ignition Facility Directorate has established criteria for a number of items found on the typical laser safety audit form. The criteria are distributed to laser users. It serves two broad purposes; first, it gives the user an expectation of what will be reviewed by an auditor. Second, it is an opportunity to explain audit items to the laser user and thus the reasons for some of these items, such as labelling of beam blocks.

  9. The drive for Aircraft Energy Efficiency

    NASA Technical Reports Server (NTRS)

    James, R. L., Jr.; Maddalon, D. V.

    1984-01-01

    NASA's Aircraft Energy Efficiency (ACEE) program, which began in 1976, has mounted a development effort in four major transport aircraft technology fields: laminar flow systems, advanced aerodynamics, flight controls, and composite structures. ACEE has explored two basic methods for achieving drag-reducing boundary layer laminarization: the use of suction through the wing structure (via slots or perforations) to remove boundary layer turbulence, and the encouragement of natural laminar flow maintenance through refined design practices. Wind tunnel tests have been conducted for wide bodied aircraft equipped with high aspect ratio supercritical wings and winglets. Maneuver load control and pitch-active stability augmentation control systems reduce fuel consumption by reducing the drag associated with high aircraft stability margins. Composite structures yield lighter airframes that in turn call for smaller wing and empennage areas, reducing induced drag for a given payload. In combination, all four areas of development are expected to yield a fuel consumption reduction of 40 percent.

  10. Eddy current arrays for wheel inspection

    NASA Astrophysics Data System (ADS)

    Leclerc, Rémi

    2001-04-01

    Wheel inspections are routine and very time-consuming, especially for large aircraft wheels where a single-coil probe is moved manually taking precious long minutes. Eddy current arrays can decrease the inspection time by reducing to one the number of rotations needed to completely cover the wheel surface. Since the EC array probe fits the profile of the wheel, manipulation is easy and the lift-off is kept constant improving signal quality. C-scan displays assist the analysis and help locate the defect by dividing the inspected wheel surface into a small grid. Furthermore, the impedance plane and the strip chart, for all the channels used to build the C-scan, are accessible to provide better sizing accuracy of the defect.

  11. Safe structures for future aircraft

    NASA Technical Reports Server (NTRS)

    Mccomb, H. G., Jr.

    1983-01-01

    The failure mechanisms, design lessons, and test equipment employed by NASA in establishing the airworthiness and crashworthiness of aircraft components for commercial applications are described. The composites test programs have progressed to medium primary structures such as stabilizers and a vertical fin. The failures encountered to date have been due to the nonyielding nature of composites, which do not diffuse loads like metals, and the presence of eccentricities, irregular shapes, stiffness changes, and discontinuities that cause tension and shear. Testing to failure, which always occurred in first tests before the design loads were reached, helped identify design changes and reinforcements that produced successful products. New materials and NDE techniques are identified, together with aircraft structural design changes that offer greater protection to the passengers, fuel antimisting agents, and landing gear systems.

  12. Propulsion controlled aircraft computer

    NASA Technical Reports Server (NTRS)

    Cogan, Bruce R. (Inventor)

    2010-01-01

    A low-cost, easily retrofit Propulsion Controlled Aircraft (PCA) system for use on a wide range of commercial and military aircraft consists of an propulsion controlled aircraft computer that reads in aircraft data including aircraft state, pilot commands and other related data, calculates aircraft throttle position for a given maneuver commanded by the pilot, and then displays both current and calculated throttle position on a cockpit display to show the pilot where to move throttles to achieve the commanded maneuver, or is automatically sent digitally to command the engines directly.

  13. Properties of aircraft tire materials

    NASA Technical Reports Server (NTRS)

    Dodge, Richard N.; Clark, Samuel K.

    1988-01-01

    A summary is presented of measured elastomeric composite response suitable for linear structural and thermoelastic analysis in aircraft tires. Both real and loss properties are presented for a variety of operating conditions including the effects of temperature and frequency. Suitable micro-mechanics models are used for predictions of these properties for other material combinations and the applicability of laminate theory is discussed relative to measured values.

  14. Integration of a code for aeroelastic design of conventional and composite wings into ACSYNT, an aircraft synthesis program. [wing aeroelastic design (WADES)

    NASA Technical Reports Server (NTRS)

    Mullen, J., Jr.

    1976-01-01

    A comparison of program estimates of wing weight, material distribution. structural loads and elastic deformations with actual Northrop F-5A/B data is presented. Correlation coefficients obtained using data from a number of existing aircraft were computed for use in vehicle synthesis to estimate wing weights. The modifications necessary to adapt the WADES code for use in the ACSYNT program are described. Basic program flow and overlay structure is outlined. An example of the convergence of the procedure in estimating wing weights during the synthesis of a vehicle to satisfy F-5 mission requirements is given. A description of inputs required for use of the WADES program is included.

  15. Vicinal light inspection of translucent materials

    DOEpatents

    Burns, Geroge R.; Yang, Pin

    2010-01-19

    The present invention includes methods and apparatus for inspecting vicinally illuminated non-patterned areas of translucent materials. An initial image of the material is received. A second image is received following a relative translation between the material being inspected and a device generating the images. Each vicinally illuminated image includes a portion having optimal illumination, that can be extracted and stored in a composite image of the non-patterned area. The composite image includes aligned portions of the extracted image portions, and provides a composite having optimal illumination over a non-patterned area of the material to be inspected. The composite image can be processed by enhancement and object detection algorithms, to determine the presence of, and characterize any inhomogeneities present in the material.

  16. AIRCRAFT DEPAINTING TECHNOLOGY

    EPA Science Inventory

    Chemical paint strippers historically used for aircraft contained toxic and hazardous components; aircraft depainting operations are a major source of hazardous waste generation in DOD. Federal and state agencies have begun to restrict using these hazardous materials and Governme...

  17. 14 CFR Appendix F to Part 43 - ATC Transponder Tests and Inspections

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false ATC Transponder Tests and Inspections F... 43—ATC Transponder Tests and Inspections The ATC transponder tests required by § 91.413 of this... coupling to the aircraft antenna system is used, operate the test equipment for ATCRBS transponders at...

  18. 14 CFR Appendix F to Part 43 - ATC Transponder Tests and Inspections

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false ATC Transponder Tests and Inspections F... 43—ATC Transponder Tests and Inspections The ATC transponder tests required by § 91.413 of this... coupling to the aircraft antenna system is used, operate the test equipment for ATCRBS transponders at...

  19. 14 CFR Appendix F to Part 43 - ATC Transponder Tests and Inspections

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false ATC Transponder Tests and Inspections F... 43—ATC Transponder Tests and Inspections The ATC transponder tests required by § 91.413 of this... coupling to the aircraft antenna system is used, operate the test equipment for ATCRBS transponders at...

  20. 49 CFR 175.88 - Inspection, orientation and securing packages of hazardous materials.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Inspection, orientation and securing packages of... REGULATIONS CARRIAGE BY AIRCRAFT Loading, Unloading and Handling § 175.88 Inspection, orientation and securing... END UP”, or with arrows to indicate the proper orientation of the package, must be stored and...