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 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...

  9. 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...

  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. 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).

  6. 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.

  7. 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.

  8. 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.

  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. 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.

  17. 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.

  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. 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.

  20. 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

  1. 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.

  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. 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.

  14. 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.

  15. 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.

  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 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.

  4. 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.

  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. 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.

  15. 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

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  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. 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.

  5. 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.

  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. 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.

  8. 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.

  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. 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.

  3. 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.

  4. 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.

  5. 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.

  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. 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.

  13. 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.

  14. 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.

  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. 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.

  2. 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.

  3. 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.

  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. 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.

  16. 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.

  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. 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.

  1. 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.

  2. 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.

  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. 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.

  7. 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.

  8. 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.

  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. 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.

  1. 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.

  2. 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.

  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, 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.

  8. 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.

  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. 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.

  8. 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.

  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.