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Sample records for adaptive truss structures

  1. Quasi-static shape estimation and control of adaptive truss structures

    NASA Technical Reports Server (NTRS)

    Kuwao, Fumihiro; Chen, Gun-Shing; Wada, Ben K.

    1991-01-01

    Methods for estimating the deformation of adaptive truss structures are proposed which employ internal displacement sensors to measure changes in the length of selected truss members. Based on the measured data from the instrumented truss member, the total truss deformation pattern can be estimated through direct interpolation. To verify the validity of the methods presented here, numerical simulations are carried out for simple plane trusses, a beam truss, and a tetrahedral truss.

  2. Adaptive Control of Truss Structures for Gossamer Spacecraft

    NASA Technical Reports Server (NTRS)

    Yang Bong-Jun; Calise, anthony J.; Craig, James I.; Whorton, Mark S.

    2007-01-01

    Neural network-based adaptive control is considered for active control of a highly flexible truss structure which may be used to support solar sail membranes. The objective is to suppress unwanted vibrations in SAFE (Solar Array Flight Experiment) boom, a test-bed located at NASA. Compared to previous tests that restrained truss structures in planar motion, full three dimensional motions are tested. Experimental results illustrate the potential of adaptive control in compensating for nonlinear actuation and modeling error, and in rejecting external disturbances.

  3. The design and development of a two-dimensional adaptive truss structure

    NASA Technical Reports Server (NTRS)

    Kuwao, Fumihiro; Motohashi, Shoichi; Yoshihara, Makoto; Takahara, Kenichi; Natori, Michihiro

    1987-01-01

    The functional model of a two dimensional adaptive truss structure which can purposefully change its geometrical configuration is introduced. The details of design and fabrication such as kinematic analysis, dynamic characteristics analysis and some test results are presented for the demonstration of this two dimensional truss concept.

  4. Lightweight structural columns. [space erectable trusses

    NASA Technical Reports Server (NTRS)

    Bush, H. G. (Inventor)

    1981-01-01

    Lightweight half-lengths of columns for truss structures are described. The columns are adapted for nestable storage and transport to facilitate fabrication of large area truss structures at a remote site and particularly adaptable for space applications.

  5. Geometry control in prestressed adaptive space trusses

    NASA Technical Reports Server (NTRS)

    Sener, Murat; Utku, Senol; Wada, Ben K.

    1993-01-01

    In this work the actuator placement problem for the precision control in prestressed adaptive space trusses is studied. These structures cannot be statically determinate, implying that the length-adjusting actuators have to work against the existing prestressing forces, and also against the stresses caused by the actuation. This type of difficulties does not exist in statically determinate adaptive trusses where, except for overcoming the friction, the actuators operate under zero axial force, and require almost no energy. The actuator placement problem in statically inderterminate trusses is, therefore, governed seriously by the energy and the strength requirements. The paper provides various methodologies for the actuator placement problem in prestressed space trusses.

  6. Synchronously deployable truss structure

    NASA Technical Reports Server (NTRS)

    Bush, H. G. (Inventor); Mikulas, M., Jr. (Inventor); Wallsom, E. (Inventor)

    1986-01-01

    A collapsible-expandable truss structure, including first and second spaced surface truss layers having an attached core layer is described. The surface truss layers are composed of a plurality of linear struts arranged in multiple triangular configurations. Each linear strut is hinged at the center and hinge connected at each end to a nodular joint. A passive spring serves as the expansion force to move the folded struts from a stowed collapsed position to a deployed operative final truss configuration. A damper controls the rate of spring expansion for the synchronized deployment of the truss as the folded configuration is released for deployment by the restrain belts. The truss is synchronously extended under the control of motor driven spools.

  7. Deployable geodesic truss structure

    NASA Technical Reports Server (NTRS)

    Mikulas, Martin M., Jr. (Inventor); Rhodes, Marvin D. (Inventor); Simonton, J. Wayne (Inventor)

    1987-01-01

    A deployable geodesic truss structure which can be deployed from a stowed state to an erected state is described. The truss structure includes a series of bays, each bay having sets of battens connected by longitudinal cross members which give the bay its axial and torsional stiffness. The cross members are hinged at their mid point by a joint so that the cross members are foldable for deployment or collapsing. The bays are deployed and stabilized by actuator means connected between the mid point joints of the cross members. Hinged longerons may be provided to also connect the sets of battens and to collapse for stowing with the rest of the truss structure.

  8. On the placement of active members in adaptive truss structures for vibration control

    NASA Technical Reports Server (NTRS)

    Lu, L.-Y.; Utku, S.; Wada, B. K.

    1992-01-01

    The problem of optimal placement of active members which are used for vibration control in adaptive truss structures is investigated. The control scheme is based on the method of eigenvalue assignment as a means of shaping the transient response of the controlled adaptive structures, and the minimization of required control action is considered as the optimization criterion. To this end, a performance index which measures the control strokes of active members is formulated in an efficient way. In order to reduce the computation burden, particularly for the case where the locations of active members have to be selected from a large set of available sites, several heuristic searching schemes are proposed for obtaining the near-optimal locations. The proposed schemes significantly reduce the computational complexity of placing multiple active members to the order of that when a single active member is placed.

  9. Flexible beam control using an adaptive truss

    NASA Technical Reports Server (NTRS)

    Warrington, Thomas J.; Horner, C. Garnett

    1990-01-01

    To demonstrate the feasibility of adaptive trusses for vibration suppression, a 12-ft-long beam is attached to a single cell of an adaptive truss which has three active battens. With the base of the adaptive truss attached to the laboratory frame, the measured strain of the vibrating beam shows the adaptive truss to be very effective in suppressing vibration when subjected to initial conditions. Control is accomplished by a PC/XT computer that implements an LQR-designed control law.

  10. Structural Truss Elements and Forces

    ERIC Educational Resources Information Center

    Troyer, Steve; Griffis, Kurt; Shackelford, Ray

    2005-01-01

    In the field of construction, most structures are supported by several groups of truss systems working together synergistically. A "truss" is a group of centered and balanced elements combined to carry a common load (Warner, 2003). Trusses provide strength against loads and forces within a structure. Though a complex field of study, structural…

  11. Truss structure design

    NASA Technical Reports Server (NTRS)

    Daily, Carl S. (Inventor); Lees, Daniel A. (Inventor); McKitterick, Dennis Donald (Inventor)

    2000-01-01

    An integrally formed three-dimensional truss structure, including molds and methods for production of same, containing outer top and bottom plane surfaces thereof comprising interconnected rod segments integrally formed at their points of intersection on the outer top and bottom surfaces, the top and bottom surfaces also integrally joined together through additional interconnected rod segments passing through an integrally formed intersection, wherein the additional interconnected rod segments passing through the integrally formed intersection form a three-dimensional continuous array of triangles.

  12. Experiments for locating damaged truss members in a truss structure

    NASA Technical Reports Server (NTRS)

    Mcgowan, Paul E.; Smith, Suzanne W.; Javeed, Mehzad

    1991-01-01

    Locating damaged truss members in large space structures will involve a combination of sensing and diagnostic techniques. Methods developed for damage location require experimental verification prior to on-orbit applications. To this end, a series of experiments for locating damaged members using a generic, ten bay truss structure were conducted. A 'damaged' member is a member which has been removed entirely. Previously developed identification methods are used in conjunction with the experimental data to locate damage. Preliminary results to date are included, and indicate that mode selection and sensor location are important issues for location performance. A number of experimental data sets representing various damage configurations were compiled using the ten bay truss. The experimental data and the corresponding finite element analysis models are available to researchers for verification of various methods of structure identification and damage location.

  13. Truss Structure Could Be Folded For Transport

    NASA Technical Reports Server (NTRS)

    Theer, Douglas S.

    1996-01-01

    Proposed truss structure comprises cubical bays and folded for compactness during transport. When folded, truss 1/25.6 as long as when fully extended. Conceived for transport and deployment in outerspace, suitable for terrestrial structures that must be transported compactly and erected quickly.

  14. Assembling Precise Truss Structures With Minimal Stresses

    NASA Technical Reports Server (NTRS)

    Sword, Lee F.

    1996-01-01

    Improved method of assembling precise truss structures involves use of simple devices. Tapered pins that fit in tapered holes indicate deviations from prescribed lengths. Method both helps to ensure precision of finished structures and minimizes residual stresses within structures.

  15. Actuator placement in prestressed adaptive trusses for vibration control

    NASA Technical Reports Server (NTRS)

    Jalihal, P.; Utku, Senol; Wada, Ben K.

    1993-01-01

    This paper describes the optimal location selection of actuators for vibration control in prestressed adaptive trusses. Since prestressed adaptive trusses are statically indeterminate, the actuators to be used for vibration control purposes must work against (1) existing static axial prestressing forces, (2) static axial forces caused by the actuation, and (3) dynamic axial forces caused by the motion of the mass. In statically determinate adaptive trusses (1) and (2) are non - existing. The actuator placement problem in statically indeterminate trusses is therefore governed by the actuation energy and the actuator strength requirements. Assuming output feedback type control of selected vibration modes in autonomous systems, a procedure is given for the placement of vibration controlling actuators in prestressed adaptive trusses.

  16. Design and operation of a deployable truss structure

    NASA Technical Reports Server (NTRS)

    Miura, K.

    1984-01-01

    A concept for the one dimensional deployable truss structure is presented. The deployed configuration of the structure consists of the repetition of a longitudinal octahedral truss module. The principal mechanical feature of the truss is that the lateral members comprising the lateral triangular truss are telescoping beams. Contracting of the lateral members results in the deployment of the truss structure. The geometric transformation of this truss of variable geometry is presented. Both simultaneous and sequential modes of transformation are possible. The validity of the transformation applied to the deployment is verified through design of a conceptual model.

  17. Passive damping for space truss structures

    NASA Technical Reports Server (NTRS)

    Chen, Gun-Shing; Wada, Ben K.

    1988-01-01

    Theoretical and experimental studies of passive damping techniques in truss-type structures are presented, with emphasis on the use of viscoelastic damping in the parallel load path. The constraining member length is shown to be a convenient design variable for enhancing damping performance. Results are presented for integral damping members made of thin-wall aluminum tubes, concentric constraining members, and viscoelastic materials in a six-bay truss structure at low frequency and low dynamic strain conditions. Integral members with graphite/epoxy constraining members exhibited relatively low damping values due to the possible polymer interaction during the cocure stage.

  18. A Teaching Model for Truss Structures

    ERIC Educational Resources Information Center

    Bigoni, Davide; Dal Corso, Francesco; Misseroni, Diego; Tommasini, Mirko

    2012-01-01

    A classroom demonstration model has been designed, machined and successfully tested in different learning environments to facilitate understanding of the mechanics of truss structures, in which struts are subject to purely axial load and deformation. Gaining confidence with these structures is crucial for the development of lattice models, which…

  19. 2. WEST ELEVATION, SHOWING ENTIRE STRUCTURE: PENNSYLVANIA TRUSS MAIN SPANS ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. WEST ELEVATION, SHOWING ENTIRE STRUCTURE: PENNSYLVANIA TRUSS MAIN SPANS AND PONY TRUSS APPROACH SPANS - Coraopolis Bridge, Spanning Ohio River back channel at Ferree Street & Grand Avenue, Coraopolis, Allegheny County, PA

  20. Experimental Dynamic Characterization of a Reconfigurable Adaptive Precision Truss

    NASA Technical Reports Server (NTRS)

    Hinkle, J. D.; Peterson, L. D.

    1994-01-01

    The dynamic behavior of a reconfigurable adaptive truss structure with non-linear joints is investigated. The objective is to experimentally examine the effects of the local non-linearities on the global dynamics of the structure. Amplitude changes in the frequency response functions are measured at micron levels of motion. The amplitude and frequency variations of a number of modes indicate a non-linear Coulomb friction response. Hysteretic bifurcation behavior is also measured at an amplitude approximately equal to the specified free-play in the joint. Under the 1 g pre-load, however, the non-linearity was dominantly characteristic of Coulomb friction with little evidence of free-play stiffening.

  1. Deployable Carbon Tape Truss for Gossamer Space Structures

    NASA Astrophysics Data System (ADS)

    Hillebrandt, Martin; Straubel, Marco; Huhne, Christian; Wiedemann, Martin

    2012-07-01

    DLR has developed a high performance deployable truss concept for very large Gossamer Space Structures such as solar sails with side length up to a few hundred meters. The truss concept is based on foldable longerons made of thin-walled carbon tapes. In comparison to longerons of solid rods - the most frequently used type for deployable trusses - they show much higher compression strength when going to high element length. This enables increasing truss bay length and radius without increase in mass. As strength and stiffness of a truss depend strongly on its radius, highly mass-efficient trusses can be realized. A small packaging ratio is gained using a two path folding pattern. Therefore, the triangular truss is flattened first in cross direction enabled by hinges added to one row of battens. In the second step the flattened truss is reeled up on a central hub taking advantage from the high deformation capability of thin-walled carbon tapes. Extensive finite-element analysis has been done as well as hardware testing of longeron specimens and a truss prototype was manufactured. Measured and calculated performance values gained by this analysis show the superiority of this new truss-concept towards established deployable mast concepts in regard to bending stiffness, bending strength and specific truss mass.

  2. Deployable M-braced truss structure

    NASA Technical Reports Server (NTRS)

    Mikulas, M. M., Jr. (Inventor); Rhodes, M. D. (Inventor)

    1986-01-01

    A deployable M-braced truss structure, efficiently packaged into a compact stowed position and expandable to an operative position at the use site is described. The M-braced configuration effectively separates tension compression and shear in the structure and permits efficient structural design. Both diagonals and longerons telescope from an M-braced base unit and deploy either pneumatically, mechanically by springs or cables, or by powered reciprocating mechanisms. Upon full deployment, the diagonals and longerons lock into place with a simple latch mechanism.

  3. Deployable-erectable trade study for space station truss structures

    NASA Technical Reports Server (NTRS)

    Mikulas, M. M., Jr.; Wright, A. S., Jr.; Bush, H. G.; Watson, J. J.; Dean, E. B.; Twigg, L. T.; Rhodes, M. D.; Cooper, P. A.; Dorsey, J. T.; Lake, M. S.

    1985-01-01

    The results of a trade study on truss structures for constructing the space station are presented. Although this study was conducted for the reference gravity gradient space station, the results are generally applicable to other configurations. The four truss approaches for constructing the space station considered in this paper were the 9 foot single fold deployable, the 15 foot erectable, the 10 foot double fold tetrahedral, and the 15 foot PACTRUSS. The primary rational for considering a 9 foot single-fold deployable truss (9 foot is the largest uncollapsed cross-section that will fit in the Shuttle cargo bay) is that of ease of initial on-orbit construction and preintegration of utility lines and subsystems. The primary rational for considering the 15 foot erectable truss is that the truss bay size will accommodate Shuttle size payloads and growth of the initial station in any dimension is a simple extension of the initial construction process. The primary rational for considering the double-fold 10 foot tetrahedral truss is that a relatively large amount of truss structure can be deployed from a single Shuttle flight to provide a large number of nodal attachments which present a pegboard for attaching a wide variety of payloads. The 15 foot double-fold PACTRUSS was developed to incorporate the best features of the erectable truss and the tetrahedral truss.

  4. SpRoUTS (Space Robot Universal Truss System): Reversible Robotic Assembly of Deployable Truss Structures of Reconfigurable Length

    NASA Technical Reports Server (NTRS)

    Jenett, Benjamin; Cellucci, Daniel; Cheung, Kenneth

    2015-01-01

    Automatic deployment of structures has been a focus of much academic and industrial work on infrastructure applications and robotics in general. This paper presents a robotic truss assembler designed for space applications - the Space Robot Universal Truss System (SpRoUTS) - that reversibly assembles a truss from a feedstock of hinged andflat-packed components, by folding the sides of each component up and locking onto the assembled structure. We describe the design and implementation of the robot and show that the assembled truss compares favorably with prior truss deployment systems.

  5. Probabilistic structural analysis of adaptive/smart/intelligent space structures

    NASA Technical Reports Server (NTRS)

    Pai, Shantaram S.; Chamis, Christos C.

    1992-01-01

    A three-bay, space, cantilever truss is probabilistically evaluated for adaptive/smart/intelligent behavior. For each behavior, the scatter (ranges) in buckling loads, vibration frequencies, and member axial forces are probabilistically determined. Sensitivities associated with uncertainties in the structure, material and load variables that describe the truss are determined for different probabilities. The relative magnitude for these sensitivities are used to identify significant truss variables that control/classify its behavior to respond as an adaptive/smart/intelligent structure. Results show that the probabilistic buckling loads and vibration frequencies increase for each truss classification, with a substantial increase for intelligent trusses. Similarly, the probabilistic member axial forces reduce for adaptive and intelligent trusses and increase for smart trusses.

  6. Probabilistic structural analysis of adaptive/smart/intelligent space structures

    NASA Technical Reports Server (NTRS)

    Pai, Shantaram S.; Chamis, Christos C.

    1991-01-01

    A three-bay, space, cantilever truss is probabilistically evaluated for adaptive/smart/intelligent behavior. For each behavior, the scatter (ranges) in buckling loads, vibration frequencies, and member axial forces are probabilistically determined. Sensitivities associated with uncertainties in the structure, material and load variables that describe the truss are determined for different probabilities. The relative magnitude for these sensitivities are used to identify significant truss variables that control/classify its behavior to respond as an adaptive/smart/intelligent structure. Results show that the probabilistic buckling loads and vibration frequencies increase for each truss classification, with a substantial increase for intelligent trusses. Similarly, the probabilistic member axial forces reduce for adaptive and intelligent trusses and increase for smart trusses.

  7. Adaptive structures to enable ground test validation of precision structures

    NASA Technical Reports Server (NTRS)

    Wada, Ben K.; Fanson, James F.; Chen, Gun-Shing; Kuo, Chin-Po

    1990-01-01

    The use of analytical models and ground-based experimental validation of precision space structures is addressed. The application of adaptive structures to such validation of precision space structures is addressed, with the focus on adaptive truss structures.

  8. Effects of joints in truss structures

    NASA Technical Reports Server (NTRS)

    Ikegami, R.

    1988-01-01

    The response of truss-type structures for future space applications, such as Large Deployable Reflector (LDR), will be directly affected by joint performance. Some of the objectives of research at BAC were to characterize structural joints, establish analytical approaches that incorporate joint characteristics, and experimentally establish the validity of the analytical approaches. The test approach to characterize joints for both erectable and deployable-type structures was based upon a Force State Mapping Technique. The approach pictorially shows how the nonlinear joint results can be used for equivalent linear analysis. Testing of the Space Station joints developed at LaRC (a hinged joint at 2 Hz and a clevis joint at 2 Hz) successfully revealed the nonlinear characteristics of the joints. The Space Station joints were effectively linear when loaded to plus or minus 500 pounds with a corresponding displacement of about plus or minus 0.0015 inch. It was indicated that good linear joints exist which are compatible with errected structures, but that difficulty may be encountered if nonlinear-type joints are incorporated in the structure.

  9. 31. LOWER CHORD / FLOOR STRUCTURE DETAIL OF THROUGH TRUSS. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    31. LOWER CHORD / FLOOR STRUCTURE DETAIL OF THROUGH TRUSS. VIEW TO NORTH. - Abraham Lincoln Memorial Bridge, Spanning Missouri River on Highway 30 between Nebraska & Iowa, Blair, Washington County, NE

  10. 32. LOWER CHORD / FLOOR STRUCTURE DETAIL OF THROUGH TRUSS. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    32. LOWER CHORD / FLOOR STRUCTURE DETAIL OF THROUGH TRUSS. VIEW TO NORTH. - Abraham Lincoln Memorial Bridge, Spanning Missouri River on Highway 30 between Nebraska & Iowa, Blair, Washington County, NE

  11. 14. DETAIL OF ROOF TRUSS STRUCTURE AND HAY HOOK CABLE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    14. DETAIL OF ROOF TRUSS STRUCTURE AND HAY HOOK CABLE AND PULLEY SYSTEM LOCATED ON WEST END OF BARN. CAMERA POINTED EAST. - James H. Lane Ranch, Barn, One Mile South of Richfield on Highway 26, Richfield, Lincoln County, ID

  12. STS-112 crew in front of S0 Truss Structure

    NASA Technical Reports Server (NTRS)

    2002-01-01

    KENNEDY SPACE CENTER, FLA. -- In the Operations and Checkout Building, the STS-112 crew stands under the S0 Integrated Truss Structure, waiting to be transported to the launch pad for mission STS-110. From left are Mission Specialist David Wolf, Pilot Pam ela Melroy; Commander Jeffrey Ashby; and Mission Specialist Piers Sellers. Mission STS-112 will be ferrying the S1 ITS to the International Space Station on its scheduled Aug. 15 flight. The S1 truss will be attached to the S0 truss

  13. Structural design feasibility study of Space Station long spacer truss

    NASA Technical Reports Server (NTRS)

    Armand, Sasan C.; Funk, Gregory P.; Dohogne, Caroline A.

    1994-01-01

    The structural design and configuration feasibility of the long spacer truss assembly that will be used as part of the Space Station Freedom is the focus of this study. The structural analysis discussed herein is derived from the transient loading events presented in the Space Transportation System Interface Control Document (STS ICD). The transient loading events are liftoff, landing, and emergency landing loads. Quasi-static loading events were neglected in this study since the magnitude of the quasi-static acceleration factors is lower than that of the transient acceleration factors. Structural analysis of the proposed configuration of the long spacer truss with four longerons indicated that negative safety margins are possible. As a result, configuration changes were proposed. The primary configuration change suggested was to increase the number of truss longerons to six. The six-longeron truss appears to be a more promising structure than the four-longeron truss because it offers a positive margin of safety and more volume in its second bay (BAY2). This additional volume can be used for resupply of some of the orbital replacement units (such as a battery box). Note that the design effort on the long spacer truss has not fully begun and that calculations and reports of the negative safety margins are, to date, based on concept only.

  14. Structural design feasibility study of Space Station long spacer truss

    NASA Astrophysics Data System (ADS)

    Armand, Sasan C.; Funk, Gregory P.; Dohogne, Caroline A.

    1994-02-01

    The structural design and configuration feasibility of the long spacer truss assembly that will be used as part of the Space Station Freedom is the focus of this study. The structural analysis discussed herein is derived from the transient loading events presented in the Space Transportation System Interface Control Document (STS ICD). The transient loading events are liftoff, landing, and emergency landing loads. Quasi-static loading events were neglected in this study since the magnitude of the quasi-static acceleration factors is lower than that of the transient acceleration factors. Structural analysis of the proposed configuration of the long spacer truss with four longerons indicated that negative safety margins are possible. As a result, configuration changes were proposed. The primary configuration change suggested was to increase the number of truss longerons to six. The six-longeron truss appears to be a more promising structure than the four-longeron truss because it offers a positive margin of safety and more volume in its second bay (BAY2). This additional volume can be used for resupply of some of the orbital replacement units (such as a battery box). Note that the design effort on the long spacer truss has not fully begun and that calculations and reports of the negative safety margins are, to date, based on concept only.

  15. On an adaptive truss manipulator space crane concept

    NASA Astrophysics Data System (ADS)

    Chen, Gun-Shing; Wada, Ben K.

    The paper describes an adaptive truss manipulator (ATM) space crane concept for in-space assembly and construction. The underlying mechanism of an ATM is that the batten members of the constituent octahedral modules are controllable in length. Through geometric transformations of the constituent modules, the basic manipulator functions such as articulation can be performed by the ATM. The mechanism can also provide deployment/retraction, high dexterity motion, and bracing operation. The advantages of an ATM over the conventional multijoint-multilink anthropomorphic manipulator are its compact stowage volume for in-space storage and mobility, deployment as needed, high dexterity in complex workspace, and high redundancy of the actuator function. The kinematic description of an ATM is formulated in the global cartesian coordinate system.

  16. On an adaptive truss manipulator space crane concept

    NASA Technical Reports Server (NTRS)

    Chen, Gun-Shing; Wada, Ben K.

    1991-01-01

    The paper describes an adaptive truss manipulator (ATM) space crane concept for in-space assembly and construction. The underlying mechanism of an ATM is that the batten members of the constituent octahedral modules are controllable in length. Through geometric transformations of the constituent modules, the basic manipulator functions such as articulation can be performed by the ATM. The mechanism can also provide deployment/retraction, high dexterity motion, and bracing operation. The advantages of an ATM over the conventional multijoint-multilink anthropomorphic manipulator are its compact stowage volume for in-space storage and mobility, deployment as needed, high dexterity in complex workspace, and high redundancy of the actuator function. The kinematic description of an ATM is formulated in the global cartesian coordinate system.

  17. Application of the ADAMS program to deployable space truss structures

    NASA Technical Reports Server (NTRS)

    Calleson, R. E.

    1985-01-01

    The need for a computer program to perform kinematic and dynamic analyses of large truss structures while deploying from a packaged configuration in space led to the evaluation of several existing programs. ADAMS (automatic dynamic analysis of mechanical systems), a generalized program from performing the dynamic simulation of mechanical systems undergoing large displacements, is applied to two concepts of deployable space antenna units. One concept is a one cube folding unit of Martin Marietta's Box Truss Antenna and the other is a tetrahedral truss unit of a Tetrahedral Truss Antenna. Adequate evaluation of dynamic forces during member latch-up into the deployed configuration is not yet available from the present version of ADAMS since it is limited to the assembly of rigid bodies. Included is a method for estimating the maximum bending stress in a surface member at latch-up. Results include member displacement and velocity responses during extension and an example of member bending stresses at latch-up.

  18. Onsite Fabrication of Trusses and Structures

    NASA Technical Reports Server (NTRS)

    Bodle, J. G.; Browning, D. L.; Fisher, J. G.; Hujsak, E. J.; Kleidon, E. H.; Siden, L. E.; Tremblay, G. A.

    1982-01-01

    Tribeam truss that is strong and light made at site where used. Reinforced plastic members are fabricated by beam-making machine and assembled by assembly and welding machines. Although proposed for space-platform assembly, concept may be useful in terrestrial applications in remote or inaccessible places.

  19. Study on light weight design of truss structures of spacecrafts

    NASA Astrophysics Data System (ADS)

    Zeng, Fuming; Yang, Jianzhong; Wang, Jian

    2015-08-01

    Truss structure is usually adopted as the main structure form for spacecrafts due to its high efficiency in supporting concentrated loads. Light-weight design is now becoming the primary concern during conceptual design of spacecrafts. Implementation of light-weight design on truss structure always goes through three processes: topology optimization, size optimization and composites optimization. During each optimization process, appropriate algorithm such as the traditional optimality criterion method, mathematical programming method and the intelligent algorithms which simulate the growth and evolution processes in nature will be selected. According to the practical processes and algorithms, combined with engineering practice and commercial software, summary is made for the implementation of light-weight design on truss structure for spacecrafts.

  20. Microdynamic modelling of joint-dominated truss-based structures

    NASA Technical Reports Server (NTRS)

    Wang, P. K. C.; Hadaegh, F. Y.

    1990-01-01

    A methodology for the mathematical modeling of preloaded joint-dominated truss-based space structures applicable in the microdynamic regime is presented. First, various factors which could affect the microdynamic behavior of joint-dominated truss structures are examined. Then, mathematical models for various types of joints involving contact deformations are derived from Hertzian contact theory. Their dynamic behavior is studied analytically and numerically by means of computer simulation. It was found that both synchronous and asynchronous oscillations having the same orders of magnitude are excited by sinusoidal load perturbations in the microdynamic regime. These oscillations persist even in the presence of light linear damping. The integration of the derived joint models with those for the elastic links of preloaded planar truss structures is discussed.

  1. Minimizing distortion in truss structures via Tabu search

    NASA Technical Reports Server (NTRS)

    Kincaid, Rex K.

    1990-01-01

    The shape control of large flexible space structures is of great interest to structural designers. A related problem is to seek ways to minimize the need for active controls by careful design and construction of the space structure. A tetrahedral truss structure that is used to support a precision segmented reflector or antenna surface is considered. The structure has a hexagonal platform and is characterized by the number of rings of members in the truss. For simplicity it is assumed that a flat truss geometry exists. Hence, all structural members and ball joints are required to have the same nominal length and diameter, respectively. Inaccuracies in the length of member or diameters of joints may produce unacceptable levels of surface distortion and internal forces. In the case of a truss structure supporting an antenna, surface distortions may cause unacceptable gain loss or pointing errors. The focus is solely on surface distortion, however, internal forces may be treated in a similar manner. To test the Tabu search code for DSQRMS the appropriate influence matrices are used for a flat, two-ring tetrahedral reflector truss generated by Green and Haftka (1989). In this example there are 102 members (NMEMB) and 31 ball joints (NJOINT) of the same nominal length, respectively. Hence, all the members may be interchanged and all the joints may be interchanged. In addition, 19 positions on the surface of the truss (NNODES) were used to measure error influences. After a variety of experiments a set of good parameters was choosen for Tabu search. The sample size at each iteration is 10*NMEMB and the short term memory size is 40. In addition four pruning rules were used to accelerate the search..

  2. Robot-friendly connector. [space truss structures

    NASA Technical Reports Server (NTRS)

    Parma, George F. (Inventor); Vandeberghe, Mark H. (Inventor); Ruiz, Steve C. (Inventor)

    1993-01-01

    Robot friendly connectors, which, in one aspect, are truss joints with two parts, a receptacle and a joint, are presented. The joints have a head which is loosely inserted into the receptacle and is then tightened and aligned. In one aspect, the head is a rounded hammerhead which initially is enclosed in the receptacle with sloppy fit provided by the shape, size, and configuration of surfaces on the head and on the receptacle.

  3. Snap-Through Instability Patterns in Truss Structures

    NASA Technical Reports Server (NTRS)

    Hrinda, Glenn A.

    2010-01-01

    Geometrically nonlinear truss structures with snap-through behavior are demonstrated by using an arc length approach within a finite element analysis. The instability patterns are equilibrium paths that are plotted throughout the snap-through event. Careful observation of these patterns helps to identify weak designs in large space structures, as well as identify desirable snap-through behavior in the miniaturization of electronic devices known as microelectromechanical systems (MEMS). Examples of highly nonlinear trusses that show snap-through behavior are examined by tracing their equilibrium paths.

  4. Probabilistic structural analysis of a truss typical for space station

    NASA Technical Reports Server (NTRS)

    Pai, Shantaram S.

    1990-01-01

    A three-bay, space, cantilever truss is probabilistically evaluated using the computer code NESSUS (Numerical Evaluation of Stochastic Structures Under Stress) to identify and quantify the uncertainties and respective sensitivities associated with corresponding uncertainties in the primitive variables (structural, material, and loads parameters) that defines the truss. The distribution of each of these primitive variables is described in terms of one of several available distributions such as the Weibull, exponential, normal, log-normal, etc. The cumulative distribution function (CDF's) for the response functions considered and sensitivities associated with the primitive variables for given response are investigated. These sensitivities help in determining the dominating primitive variables for that response.

  5. Automated assembly of a tetrahedral truss structure using machine vision

    NASA Technical Reports Server (NTRS)

    Doggett, William R.

    1992-01-01

    The Automated Structures Assembly Laboratory is a unique facility at NASA Langley Research Center used to investigate the robotic assembly of truss structures. Two special-purpose end-effectors have been used to assemble 102 truss members and 12 panels into an 8-meter diameter structure. One end-effector is dedicated to truss member insertion, while a second end-effector is used to install panels. Until recently, the robot motions required to construct the structure were developed iteratively using the facility hardware. Recent work at Langley has resulted in a compact machine vision system capable of providing position information relative to targets on the structure. Use of the vision system to guide the robot from an approach point 10 to 18 inches from the structure, offsetting model inaccuracies, permits robot motion based on calculated points as a first step toward use of preplanned paths from an automated path planner. This paper presents recent work at Langley highlighting the application of the machine vision system during truss member insertion.

  6. Structural stiffness, strength and dynamic characteristics of large tetrahedral space truss structures

    NASA Technical Reports Server (NTRS)

    Mikulas, M. M., Jr.; Bush, H. G.; Card, M. F.

    1977-01-01

    Physical characteristics of large skeletal frameworks for space applications are investigated by analyzing one concept: the tetrahedral truss, which is idealized as a sandwich plate with isotropic faces. Appropriate analytical relations are presented in terms of the truss column element properties which for calculations were taken as slender graphite/epoxy tubes. Column loads, resulting from gravity gradient control and orbital transfer, are found to be small for the class structure investigated. Fundamental frequencies of large truss structures are shown to be an order of magnitude lower than large earth based structures. Permissible loads are shown to result in small lateral deflections of the truss due to low-strain at Euler buckling of the slender graphite/epoxy truss column elements. Lateral thermal deflections are found to be a fraction of the truss depth using graphite/epoxy columns.

  7. A structural design methodology for large angle articulated trusses considering realistic joint modeling

    NASA Astrophysics Data System (ADS)

    Thorwald, Gregory; Mikulas, Martin M., Jr.

    1994-01-01

    A structural design methodology is developed by quantifying the magnitude that large angle articulations and realistic modeling considerations adversely affect a truss's structural stiffness. Batten actuators provide the ability for the truss both to deploy and articulate. Such an articulated truss can be used in space crane applications. With geometry and modeling considerations identified and examined, strategies to alleviate the truss's stiffness reduction are developed and evaluated. Using these strategies, an improved articulated truss is then demonstrated. Observing that the design strategies are effective for the planar truss models similar 3-D truss models are then analyzed. The results show that the improvement strategies benefit both the 2-D and 3-D truss models.

  8. Research on the support truss structure of foreign space remote sensor with large-scale and flexibility

    NASA Astrophysics Data System (ADS)

    An, Mingxin; Dong, Jihong; Li, Wei; Guo, Quanfeng; Li, Yan-chun; Zhao, Weiguo; Wang, Haiping

    2014-09-01

    The truss structure had the merits of simple configuration, reliable, flexible assembly, specific stiffness and strong design ability. It was widely used in the support structure of Space camera and large telescope at home and abroad. The article described and analyzed truss structures of ground-based telescopes, space-based telescopes and Space camera. Conclusions that some reference should be followed in the truss design process were given. Simultaneously it also introduced the basic knowledge of truss design optimization, including the optimization ideas of truss structure and optimization algorithm of truss structure, which laid a good foundation for optimal design of truss in future.

  9. Planning Assembly Of Large Truss Structures In Outer Space

    NASA Technical Reports Server (NTRS)

    De Mello, Luiz S. Homem; Desai, Rajiv S.

    1992-01-01

    Report dicusses developmental algorithm used in systematic planning of sequences of operations in which large truss structures assembled in outer space. Assembly sequence represented by directed graph called "assembly graph", in which each arc represents joining of two parts or subassemblies. Algorithm generates assembly graph, working backward from state of complete assembly to initial state, in which all parts disassembled. Working backward more efficient than working forward because it avoids intermediate dead ends.

  10. Modeling of joints for the dynamic analysis of truss structures

    NASA Technical Reports Server (NTRS)

    Belvin, W. Keith

    1987-01-01

    An experimentally-based method for determining the stiffness and damping of truss joints is described. The analytical models use springs and both viscous and friction dampers to simulate joint load-deflection behavior. A least-squares algorithm is developed to identify the stiffness and damping coefficients of the analytical joint models from test data. The effects of nonlinear joint stiffness such as joint dead band are also studied. Equations for predicting the sensitivity of beam deformations to changes in joint stiffness are derived and used to show the level of joint stiffness required for nearly rigid joint behavior. Finally, the global frequency sensitivity of a truss structure to random perturbations in joint stiffness is discussed.

  11. Minimizing distortion in truss structures - A Hopfield network solution

    NASA Technical Reports Server (NTRS)

    Fu, B.; Hajela, P.

    1992-01-01

    Distortions in truss structures can result from random errors in element lengths that are typical of a manufacturing process. These distortions may be minimized by an optimal selection of elements from those available for placement between the prescribed nodes - a combinatorial optimization problem requiring significant investment of computational resource for all but the smallest problems. The present paper describes a formulation in which near-optimal element assignments are obtained as minimum-energy stable states, of an analogous Hopfield neural network. This requires mapping of the optimization problem into an energy function of the appropriate Liapunov form. The computational architecture is ideally suited to a parallel processor implementation and offers significant savings in computational effort. A numerical implementation of the approach is discussed with reference to planar truss problems.

  12. Minimizing distortion in truss structures -- a Hopfield network solution

    NASA Technical Reports Server (NTRS)

    Fu, B.; Hajela, P.

    1993-01-01

    Distortions in truss structures can result from random errors in elemental lengths that are typical of a manufacturing process. These distortions may be minimized by an optimal selection of elements from those available for placement between the prescribed nodes -- a combinatorial optimization problem requiring significant investment of computational resource for all but the smallest problems. The present paper describes a formulation in which near-optimal element assignments are obtained as minimum energy, stable states, of an analogous Hopfield neural network. This requires mapping of the optimization problem into an energy function of the appropriate Lyapunov form. The computational architecture is ideally suited to a parallel processor implementation and offers significant savings in computational effort. A numerical implementation of the approach is discussed with reference to planar truss problems.

  13. Verification Test of Automated Robotic Assembly of Space Truss Structures

    NASA Technical Reports Server (NTRS)

    Rhodes, Marvin D.; Will, Ralph W.; Quach, Cuong C.

    1995-01-01

    A multidisciplinary program has been conducted at the Langley Research Center to develop operational procedures for supervised autonomous assembly of truss structures suitable for large-aperture antennas. The hardware and operations required to assemble a 102-member tetrahedral truss and attach 12 hexagonal panels were developed and evaluated. A brute-force automation approach was used to develop baseline assembly hardware and software techniques. However, as the system matured and operations were proven, upgrades were incorporated and assessed against the baseline test results. These upgrades included the use of distributed microprocessors to control dedicated end-effector operations, machine vision guidance for strut installation, and the use of an expert system-based executive-control program. This paper summarizes the developmental phases of the program, the results of several assembly tests, and a series of proposed enhancements. No problems that would preclude automated in-space assembly or truss structures have been encountered. The test system was developed at a breadboard level and continued development at an enhanced level is warranted.

  14. Truss beam having convex-curved rods, shear web panels, and self-aligning adapters

    NASA Technical Reports Server (NTRS)

    Fernandez, Ian M. (Inventor)

    2013-01-01

    A truss beam comprised of a plurality of joined convex-curved rods with self-aligning adapters (SAA) adhesively attached at each end of the truss beam is disclosed. Shear web panels are attached to adjacent pairs of rods, providing buckling resistance for the truss beam. The rods are disposed adjacent to each other, centered around a common longitudinal axis, and oriented so that adjacent rod ends converge to at least one virtual convergence point on the common longitudinal axis, with the rods' curvature designed to increase prevent buckling for the truss beam. Each SAA has longitudinal bores that provide self-aligning of the rods in the SAA, the self-aligning feature enabling creation of strong adhesive bonds between each SAA and the rods. In certain embodiments of the present invention, pultruded unidirectional carbon fiber rods are coupled with carbon fiber shear web panels and metal SAA(s), resulting in a lightweight, low-cost but strong truss beam that is highly resistant to buckling.

  15. Lattice Truss Structural Response Using Energy Methods

    NASA Technical Reports Server (NTRS)

    Kenner, Winfred Scottson

    1996-01-01

    A deterministic methodology is presented for developing closed-form deflection equations for two-dimensional and three-dimensional lattice structures. Four types of lattice structures are studied: beams, plates, shells and soft lattices. Castigliano's second theorem, which entails the total strain energy of a structure, is utilized to generate highly accurate results. Derived deflection equations provide new insight into the bending and shear behavior of the four types of lattices, in contrast to classic solutions of similar structures. Lattice derivations utilizing kinetic energy are also presented, and used to examine the free vibration response of simple lattice structures. Derivations utilizing finite element theory for unique lattice behavior are also presented and validated using the finite element analysis code EAL.

  16. Adaptive Multi-Layer LMS Controller Design and Application to Active Vibration Suppression on a Truss and Proposed Impact Analysis Technique

    NASA Technical Reports Server (NTRS)

    Barney, Timothy A.; Shin, Y. S.; Agrawal, B. N.

    2001-01-01

    This research develops an adaptive controller that actively suppresses a single frequency disturbance source at a remote position and tests the system on the NPS Space Truss. The experimental results are then compared to those predicted by an ANSYS finite element model. The NPS space truss is a 3.7-meter long truss that simulates a space-borne appendage with sensitive equipment mounted at its extremities. One of two installed piezoelectric actuators and an Adaptive Multi-Layer LMS control law were used to effectively eliminate an axial component of the vibrations induced by a linear proof mass actuator mounted at one end of the truss. Experimental and analytical results both demonstrate reductions to the level of system noise. Vibration reductions in excess of 50dB were obtained through experimentation and over 100dB using ANSYS, demonstrating the ability to model this system with a finite element model. This report also proposes a method to use distributed quartz accelerometers to evaluate the location, direction, and energy of impacts on the NPS space truss using the dSPACE data acquisition and processing system to capture the structural response and compare it to known reference Signals.

  17. Distributed parameter modeling of repeated truss structures

    NASA Technical Reports Server (NTRS)

    Wang, Han-Ching

    1994-01-01

    A new approach to find homogeneous models for beam-like repeated flexible structures is proposed which conceptually involves two steps. The first step involves the approximation of 3-D non-homogeneous model by a 1-D periodic beam model. The structure is modeled as a 3-D non-homogeneous continuum. The displacement field is approximated by Taylor series expansion. Then, the cross sectional mass and stiffness matrices are obtained by energy equivalence using their additive properties. Due to the repeated nature of the flexible bodies, the mass, and stiffness matrices are also periodic. This procedure is systematic and requires less dynamics detail. The first step involves the homogenization from a 1-D periodic beam model to a 1-D homogeneous beam model. The periodic beam model is homogenized into an equivalent homogeneous beam model using the additive property of compliance along the generic axis. The major departure from previous approaches in literature is using compliance instead of stiffness in homogenization. An obvious justification is that the stiffness is additive at each cross section but not along the generic axis. The homogenized model preserves many properties of the original periodic model.

  18. Combined structures-controls optimization of lattice trusses

    NASA Technical Reports Server (NTRS)

    Balakrishnan, A. V.

    1991-01-01

    The role that distributed parameter model can play in CSI is demonstrated, in particular in combined structures controls optimization problems of importance in preliminary design. Closed form solutions can be obtained for performance criteria such as rms attitude error, making possible analytical solutions of the optimization problem. This is in contrast to the need for numerical computer solution involving the inversion of large matrices in traditional finite element model (FEM) use. Another advantage of the analytic solution is that it can provide much needed insight into phenomena that can otherwise be obscured or difficult to discern from numerical computer results. As a compromise in level of complexity between a toy lab model and a real space structure, the lattice truss used in the EPS (Earth Pointing Satellite) was chosen. The optimization problem chosen is a generic one: of minimizing the structure mass subject to a specified stability margin and to a specified upper bond on the rms attitude error, using a co-located controller and sensors. Standard FEM treating each bar as a truss element is used, while the continuum model is anisotropic Timoshenko beam model. Performance criteria are derived for each model, except that for the distributed parameter model, explicit closed form solutions was obtained. Numerical results obtained by the two model show complete agreement.

  19. Effect of Nonlinear Joints on Space Deployable Truss Structures

    NASA Astrophysics Data System (ADS)

    Guo, Hongwei; Deng, Zhongquan; Wu, Xiang; Liu, Rongqiang

    2012-07-01

    Joints nonlinearities with characteristics of freeplay and hysteresis are analyzed by describing joint nonlinear force-displacement based on describing function method. The nonlinear dynamic responses of the one- DOF system with joints under different exciting force levels are presented in the charts. The influence of the characterizing parameters, e.g., gaps, slipping forces of the joints on nonlinearities is analyzed. The nonlinear effects of freeplay and hysteresis present that the dynamic responses switch from one resonance frequency to another frequency when amplitude exceed the demarcation values. The hysteresis nonlinearity contributes nonlinear damping to the system. Dynamic responses of the modular beam-like deployable joint- dominated truss structure are tested under different sinusoidal exciting force levels which show obvious nonlinear behaviors. The nonlinear dynamic behaviors of the truss structure contributed by the joints shows a shift to lower resonance frequency and higher amplitude with the exciting force increases. The nonlinearity of the joints in the tested structure is identified to meet with the hysteresis nonlinearity. The experiment validates that describing method is an effective tool to model the joint nonlinearities.

  20. Semi-active damping of large space truss structures using friction joints

    NASA Astrophysics Data System (ADS)

    Gaul, Lothar; Albrecht, Hans; Wirnitzer, Jan

    2002-11-01

    The low structural damping of large space structures and the stringent positioning requirements in missions demand effective vibration suppression. The semi-active approach at hand is based on friction damping due to interfacial slip in semi-active joints which can be controlled by varying the normal pressure in the contact area using a piezo-stack actuator. This paper focuses on the modeling, identification and model reduction of a large space structure with semi-active joints. For the purpose of model identification and model reduction, the nonlinear friction forces transmitted in the joints are considered as external forces acting on the linear tress structure. Experimental Modal Analysis results are used to update the FE model of the truss structure and the parameters of the nonlinear friction model are identified from measured responses of an isolated joint. The model of the linear subsystem is reduced by a combination of balanced reduction and matching moments method. The modal truncation is based on controllability and observability gramians. To improve the fidelity locations conventional connections are replaced by adaptive joints, each with a local feedback controller for the adaptation of the normal force. Simulation results of a 10-bay truss structure with semi-active joints show the potential of the present approach.

  1. A mathematical basis for the design and design optimization of adaptive trusses in precision control

    NASA Technical Reports Server (NTRS)

    Das, S. K.; Utku, S.; Chen, G.-S.; Wada, B. K.

    1991-01-01

    A mathematical basis for the optimal design of adaptive trusses to be used in supporting precision equipment is provided. The general theory of adaptive structures is introduced, and the global optimization problem of placing a limited number, q, of actuators, so as to maximally achieve precision control and provide prestress, is stated. Two serialized optimization problems, namely, optimal actuator placement for prestress and optimal actuator placement for precision control, are addressed. In the case of prestressing, the computation of a 'desired' prestress is discussed, the interaction between actuators and redundants in conveying the prestress is shown in its mathematical form, and a methodology for arriving at the optimal placement of actuators and additional redundants is discussed. With regard to precision control, an optimal placement scheme (for q actuators) for maximum 'authority' over the precision points is suggested. The results of the two serialized optimization problems are combined to give a suboptimal solution to the global optimization problem. A method for improving this suboptimal actuator placement scheme by iteration is presented.

  2. Structural characterization of a first-generation articulated-truss joint for space crane application

    NASA Technical Reports Server (NTRS)

    Sutter, Thomas R.; Wu, K. Chauncey; Riutort, Kevin T.; Laufer, Joseph B.; Phelps, James E.

    1992-01-01

    A first-generation space crane articulated-truss joint was statically and dynamically characterized in a configuration that approximated an operational environment. The articulated-truss joint was integrated into a test-bed for structural characterization. Static characterization was performed by applying known loads and measuring the corresponding deflections to obtain load-deflection curves. Dynamic characterization was performed using modal testing to experimentally determine the first six mode shapes, frequencies, and modal damping values. Static and dynamic characteristics were also determined for a reference truss that served as a characterization baseline. Load-deflection curves and experimental frequency response functions are presented for the reference truss and the articulated-truss joint mounted in the test-bed. The static and dynamic experimental results are compared with analytical predictions obtained from finite element analyses. Load-deflection response is also presented for one of the linear actuators used in the articulated-truss joint. Finally, an assessment is presented for the predictability of the truss hardware used in the reference truss and articulated-truss joint based upon hardware stiffness properties that were previously obtained during the Precision Segmented Reflector (PSR) Technology Development Program.

  3. Tubular space truss structure for SKITTER 2 robot

    NASA Technical Reports Server (NTRS)

    Beecham, Richard; Dejulio, Linda; Delorme, Paul; Eck, Eric; Levy, Avi; Lowery, Joel; Radack, Joe; Sheffield, Randy; Stevens, Scott

    1988-01-01

    The Skitter 2 is a three legged transport vehicle designed to demonstrate the principle of a tripod walker in a multitude of environments. The tubular truss model of Skitter 2 is a proof of principal design. The model will replicate the operational capabilities of Skitter 2 including its ability to self-right itself. The project's focus was on the use of light weight tubular members in the final structural design. A strong design for the body was required as it will undergo the most intense loading. Triangular geometry was used extensively in the body, providing the required structural integrity and eliminating the need for cumbersome shear panels. Both the basic femur and tibia designs also relied on the strong geometry of the triangle. An intense literature search aided in the development of the most suitable weld techniques, joints, linkages, and materials required for a durable design. The hinge design features the use of spherical rod end bearings. In order to obtain a greater range of mobility in the tibia, a four-bar linkage was designed which attaches both to the femur and the tibia. All component designs, specifically the body, femur, and the tibia were optimized using the software package IDEAS 3.8A Supertab. The package provided essential deformation and stress analysis information on each component's design. The final structure incurred only a 0.0544 inch deflection in a maximum (worst case) loading situation. The highest stress experienced by any AL6061-T6 tubular member was 1920 psi. The structural integrity of the final design facilitated the use of Aluminum 6061-T6 tubing. The tubular truss structure of Skitter 2 is an effective and highly durable design. All facets of the design are structurally sound and cost effective.

  4. Tubular space truss structure for SKITTER 2 robot

    NASA Astrophysics Data System (ADS)

    Beecham, Richard; Dejulio, Linda; Delorme, Paul; Eck, Eric; Levy, Avi; Lowery, Joel; Radack, Joe; Sheffield, Randy; Stevens, Scott

    1988-05-01

    The Skitter 2 is a three legged transport vehicle designed to demonstrate the principle of a tripod walker in a multitude of environments. The tubular truss model of Skitter 2 is a proof of principal design. The model will replicate the operational capabilities of Skitter 2 including its ability to self-right itself. The project's focus was on the use of light weight tubular members in the final structural design. A strong design for the body was required as it will undergo the most intense loading. Triangular geometry was used extensively in the body, providing the required structural integrity and eliminating the need for cumbersome shear panels. Both the basic femur and tibia designs also relied on the strong geometry of the triangle. An intense literature search aided in the development of the most suitable weld techniques, joints, linkages, and materials required for a durable design. The hinge design features the use of spherical rod end bearings. In order to obtain a greater range of mobility in the tibia, a four-bar linkage was designed which attaches both to the femur and the tibia. All component designs, specifically the body, femur, and the tibia were optimized using the software package IDEAS 3.8A Supertab. The package provided essential deformation and stress analysis information on each component's design. The final structure incurred only a 0.0544 inch deflection in a maximum (worst case) loading situation. The highest stress experienced by any AL6061-T6 tubular member was 1920 psi. The structural integrity of the final design facilitated the use of Aluminum 6061-T6 tubing. The tubular truss structure of Skitter 2 is an effective and highly durable design. All facets of the design are structurally sound and cost effective.

  5. Stiffness and strength tailoring in uniform space-filling truss structures

    NASA Technical Reports Server (NTRS)

    Lake, Mark S.

    1992-01-01

    A deterministic procedure for tailoring the continuum stiffness and strength of uniform space-filling truss structures, through the appropriate selection of truss geometry and member sizes (flexural stiffness, axial stiffness, and length), is presented. The trusses considered herein are generated by uniform replication of a characteristic truss cell. The repeating cells are categorized by one of a set of possible geometric symmetry groups derived using crystallographic techniques. The elastic symmetry associated with each geometric symmetry group is identified to help select an appropriate truss geometry for a given application. Stiffness and strength tailoring of a given truss geometry is enabled through explicit expressions relating the continuum stiffnesses and failure stresses of the truss to the stiffnesses and failure loads of its members. These expressions are derived using an existing equivalent continuum analysis technique and a newly developed analytical failure theory for trusses. Several examples are presented to illustrate the application of these techniques and to demonstrate the usefulness of the information gained from this analysis.

  6. Stiffness and strength tailoring in uniform space-filling truss structures

    NASA Technical Reports Server (NTRS)

    Lake, Mark S.

    1992-01-01

    This paper presents a deterministic procedure for tailoring the continuum stiffness and strength of uniform space-filling truss structures through the appropriate selection of truss geometry and member sizes (i.e., flexural and axial stiffnesses and length). The trusses considered herein are generated by replication of a characteristic truss cell uniformly through space. The repeating cells are categorized by one of a set of possible geometric symmetry groups derived using the techniques of crystallography. The elastic symmetry associated with each geometric symmetry group is identified to aid in the selection of an appropriate truss geometry for a given application. Stiffness and strength tailoring of a given truss geometry is enabled through explicit expressions relating the continuum stiffnesses and failure stresses of the truss to the stiffnesses and failure loads of its members. These expressions are derived using an existing equivalent continuum analysis technique and a newly developed analytical failure theory for trusses. Several examples are presented to illustrate the application of these techniques, and to demonstrate the usefulness of the information gained from this analysis.

  7. PD control for vibration attenuation in Hoop truss structure based on a novel piezoelectric bending actuator

    NASA Astrophysics Data System (ADS)

    Luo, Yajun; Xu, Minglong; Yan, Bo; Zhang, Xinong

    2015-03-01

    With increasing of the geometry of various space structures, they easily bring low-frequency, longtime and more bending modal responses. Therefore, it is necessary to suppress effectually the vibration responses above. Adaptive structure design is a common method using the piezoelectric material. However, the conventional piezoelectric actuators hardly control effectually these responses owing to the inadequate actuated performance. This paper first introduces the design of a new dual-stack piezoelectric actuator, which has the bidirectional (can act in both push and pull directions) actuated advantage, using a pair of matching piezoelectric stacks within the actuator house. Two stacks are integrated in a mechanically opposing configuration and are electrically operated out of phase. Further, we design the piezoelectric bending actuator using two dual-stack piezoelectric actuators and a fixed device, and then a five-meter hoop truss can use it to perform the active vibration control. Here the truss is mainly applied to simulate a large hoop mesh antenna. Then, we set up the active control system based on the PD algorithm and build the simulation model by the Matlab/Simulink platform. The simulation results point out the PBA can produce enough actuated moment to suppress effectually the first-order modal response of the hoop truss. Finally, we perform three experiments including one uncontrolled case and two PD controlled cases. The two control cases mainly consider whether the driving voltages are offset or not. The experimental results of both control cases are in accordance with the better simulated analysis. The control ratios of the decay time of the first-order modal response are up to more than 30 percent in the simulations and experiments. That is, this bending actuator has good application foreground in controlling the bending modes of the spacecrafts with a larger size.

  8. Locating damaged members in a truss structure using modal test data - A demonstration experiment

    NASA Technical Reports Server (NTRS)

    Smith, Suzanne Weaver; Mcgowan, Paul E.

    1989-01-01

    An experiment is designed to demonstrate and verify the performance of the on-orbit assessment approach for large flexible space truss structures. The on-orbit assessment approach can be accomplished, in principle, with dynamic response information, structural identification methods, and model correlation techniques which produce an adjusted mathematical model. An optimal update of the structure model is formed using the response data, then examined to locate damaged members. The experiment uses a laboratory scale model truss structure which exhibits characteristics expected for large space truss structures. Vibration experiments are performed to generate response data for the damaged truss. The damage location approach is described, as well as analytical work performed in support of the vibration tests, the measured response of the test article, and some preliminary results.

  9. Locating Damaged Members in a Truss Structure Using Modal Test Data: a Demonstration Experiment

    NASA Technical Reports Server (NTRS)

    Smith, Suzanne Weaver; Mcgowan, Paul E.

    1989-01-01

    On-orbit assessment of large flexible space truss structures can be accomplished, in principle, with dynamic response information, structural identification methods, and model correlation techniques which produce an adjusted mathematical model. In a previously developed approach for damage location, an optimal update of the structure model is formed using the response data, then examined to locate damaged members. An experiment designed to demonstrate and verify the performance of the on-orbit assessment approach uses a laboratory scale model truss structure which exhibits characteristics expected for large space truss structures. Vibration experiments were performed to generate response data for the damaged truss. The damage location approach, analytical work performed in support of the vibration tests, the measured response of the test article, and some preliminary results are described.

  10. The integration of a mesh reflector to a 15-foot box truss structure. Task 3: Box truss analysis and technology development

    NASA Technical Reports Server (NTRS)

    Bachtell, E. E.; Thiemet, W. F.; Morosow, G.

    1987-01-01

    To demonstrate the design and integration of a reflective mesh surface to a deployable truss structure, a mesh reflector was installed on a 15 foot box truss cube. The specific features demonstrated include: (1) sewing seams in reflective mesh; (2) mesh stretching to desired preload; (3) installation of surface tie cords; (4) installation of reflective surface on truss; (5) setting of reflective surface; (6) verification of surface shape/accuracy; (7) storage and deployment; (8) repeatability of reflector surface; and (9) comparison of surface with predicted shape using analytical methods developed under a previous task.

  11. Loading mode dependent effective properties of octet-truss lattice structures using 3D-printing

    NASA Astrophysics Data System (ADS)

    Challapalli, Adithya

    Cellular materials, often called lattice materials, are increasingly receiving attention for their ultralight structures with high specific strength, excellent impact absorption, acoustic insulation, heat dissipation media and compact heat exchangers. In alignment with emerging additive manufacturing (AM) technology, realization of the structural applications of the lattice materials appears to be becoming faster. Considering the direction dependent material properties of the products with AM, by directionally dependent printing resolution, effective moduli of lattice structures appear to be directionally dependent. In this paper, a constitutive model of a lattice structure, which is an octet-truss with a base material having an orthotropic material property considering AM is developed. In a case study, polyjet based 3D printing material having an orthotropic property with a 9% difference in the principal direction provides difference in the axial and shear moduli in the octet-truss by 2.3 and 4.6%. Experimental validation for the effective properties of a 3D printed octet-truss is done for uniaxial tension and compression test. The theoretical value based on the micro-buckling of truss member are used to estimate the failure strength. Modulus value appears a little overestimate compared with the experiment. Finite element (FE) simulations for uniaxial compression and tension of octettruss lattice materials are conducted. New effective properties for the octet-truss lattice structure are developed considering the observed behavior of the octet-truss structure under macroscopic compression and tension trough simulations.

  12. Adaptive structures - Test hardware and experimental results

    NASA Technical Reports Server (NTRS)

    Wada, Ben K.; Fanson, James L.; Chen, Gun-Shing; Kuo, Chin-Po

    1990-01-01

    The facilities and procedures used at JPL to test adaptive structures such as the large deployable reflector (LDR) are described and preliminary results are reported. The applications of adaptive structures in future NASA missions are outlined, and the techniques which are employed to modify damping, stiffness, and isolation characteristics, as well as geometric changes, are listed. The development of adaptive structures is shown to be effective as a result of new actuators and sensors, and examples are listed for categories such as fiber optics, shape-memory materials, piezoelectrics, and electrorheological fluids. Some ground test results are described for laboratory truss structures and truss test beds, which are shown to be efficient and easy to assemble in space. Adaptive structures are shown to be important for precision space structures such as the LDR, and can alleviate ground test requirements.

  13. Testing and application of a viscous passive damper for use in precision truss structures

    NASA Technical Reports Server (NTRS)

    Trubert, M.; Fanson, J.; Davis, P.; Anderson, E.

    1991-01-01

    A passive damping device intended to replace individual struts in precision truss structures for space applications is described. The theory of operation of the D-Strut device is detailed, and simple five- and three-parameter models are derived. Results from tests conducted to characterize the D-Strut at submicron displacement levels are reporeted. The incorporation of a strut in a precision truss testbed is described. Parameters determined from the component-level tests are used in a finite element model of the truss, and damping augmentation is predicted. Using the simple three-parameter model, a damper is selected for multiple placement in a separate optical interferometer truss testbed. The effect of the addition of the damper struts is illustrated analytically in a model of the structure. Finally, an improved Arched Flexure D-Strut that is expected to provide higher loss factors, and is currently under development, is described.

  14. Efficient development and processing of thermal math models of very large space truss structures

    NASA Technical Reports Server (NTRS)

    Warren, Andrew H.; Arelt, Joseph E.; Lalicata, Anthony L.

    1993-01-01

    As the spacecraft moves along the orbit, the truss members are subjected to direct and reflected solar, albedo and planetary infra-red (IR) heating rates, as well as IR heating and shadowing from other spacecraft components. This is a transient process with continuously changing heating loads and the shadowing effects. The resulting nonuniform temperature distribution may cause nonuniform thermal expansion, deflection and stress in the truss elements, truss warping and thermal distortions. There are three challenges in the thermal-structural analysis of the large truss structures. The first is the development of the thermal and structural math models, the second - model processing, and the third - the data transfer between the models. All three tasks require considerable time and computer resources to be done because of a very large number of components involved. To address these challenges a series of techniques of automated thermal math modeling and efficient processing of very large space truss structures were developed. In the process the finite element and finite difference methods are interfaced. A very substantial reduction of the quantity of computations was achieved while assuring a desired accuracy of the results. The techniques are illustrated on the thermal analysis of a segment of the Space Station main truss.

  15. Structural Analyses of the Support Trusses for the Nuclear Thermal Rocket Engines and Drop Tanks

    NASA Astrophysics Data System (ADS)

    Myers, David E.; Kosareo, Daniel N.

    2006-01-01

    Finite element structural analyses were performed on the support trusses of the Nuclear Thermal Rocket (NTR) engines and drop tanks to verify that the proper amount of mass was allocated for these components in the vehicle sizing model. The verification included a static stress analysis, a modal analysis, and a buckling analysis using the MSC/NASTRAN™ structural analysis software package. In addition, a crippling stress analysis was performed on the truss beams using a handbook equation. Two truss configurations were examined as possible candidates for the drop tanks truss while a baseline was examined for the engine support thrust structure. For the drop tanks trusses, results showed that both truss configurations produced similar results although one performed slightly better in buckling. In addition, it was shown that the mass allocated in the vehicle sizing model was adequate although the engine thrust structure may need to be modified slightly to increase its lateral natural frequency above the minimum requirement of 8 Hz that is specified in the Delta IV Payload Planners Guide.

  16. Finite element-finite difference thermal/structural analysis of large space truss structures

    NASA Technical Reports Server (NTRS)

    Warren, Andrew H.; Arelt, Joseph E.; Eskew, William F.; Rogers, Karen M.

    1992-01-01

    A technique of automated and efficient thermal-structural processing of truss structures that interfaces the finite element and finite difference method was developed. The thermal-structural analysis tasks include development of the thermal and structural math models, thermal analysis, development of an interface and data transfer between the models, and finally an evaluation of the thermal stresses and displacements in the structure. Consequently, the objective of the developed technique was to minimize the model development time, in order to assure an automatic transfer of data between the thermal and structural models as well as to minimize the computer resources needed for the analysis itself. The method and techniques described are illustrated on the thermal/structural analysis of the Space Station Freedom main truss.

  17. On the Sensitivity of Piezoceramics and Piezopolymers in Structural Integrity Monitoring of Large Trusses

    NASA Technical Reports Server (NTRS)

    Abatan, A. O.; Lin, M. W.; Mintz, E.

    1996-01-01

    An analytical assessment has been made of the reliability of using integrated microactuators and sensors in the form of piezoceramics and piezopolymers as joint integrity monitors in trussed systems. The concept is first implemented for a simple structure which consists of two truss members with a 45 deg lift angle joined at the apex. A piezoceramic patch (or piezopolymer film) bonded on the surface of one of the members at a location near the joint is used as a collocated actuator/sensor. The overall structural dynamic response under an excitation was modeled by finite element method. Different degrees of nodal constraints at the joints representing various degrees of joint integrity are employed. The resulting dynamic response showed distinct responses for varying joint stiffnesses. Parallel experimental work on a truss model using a multichannel data acquisition system and a digital signal analyzer confirms the results from analysis. We further studied the sensitivity of the micro-sensors to the behavior of joints of large arch truss structure. Results obtained for large trusses with many degrees of freedom indicate optimum locations of sensors for which the dynamic response signatures are distinct and distinguishable for relatively small changes in joint integrity and/or structural geometry. Computations based on finite element modeling show that locating the single actuator/sensor at the joint corresponding to the first loss of static stability appear optimal. Hence, static stability analysis of complex trusses can give us a good indication of the optimum placement of sensors for maximum response. This observation is important if few distributed sensors and actuators are available for placement in constructed facilities made from large trusses with many degrees of freedom. As an extension of this work a dynamic response signature identification technique to monitor in-service degradation of joints is under development for application to the monitoring of the

  18. Structural damage detection of space truss structures using best achievable eigenvectors

    NASA Astrophysics Data System (ADS)

    Lim, Tae W.; Kashangaki, Thomas A. L.

    1994-05-01

    A method is presented by which measured modes and frequencies from a modal test can be used to determine the location and magnitude of damage in a space truss structure. The damage is located by computing the Euclidean distances between the measured mode shapes and the best achievable eigenvectors. The best achievable eigenvectors are the projection of the measured mode shapes onto the subspace defined by the refined analytical model of the structure and the measured frequencies. Loss of both stiffness and mass properties can be located and quantified. To examine the performance of the method when experimentally measured modes are employed, various damage detection studies using a laboratory eight-bay truss structure were conducted. The method performs well even though the measurement errors inevitably make the damage location more difficult.

  19. A unified stochastic framework for robust topology optimization of continuum and truss-like structures

    NASA Astrophysics Data System (ADS)

    Richardson, J. N.; Filomeno Coelho, R.; Adriaenssens, S.

    2016-02-01

    In this article, a unified framework is introduced for robust structural topology optimization for 2D and 3D continuum and truss problems. The uncertain material parameters are modelled using a spatially correlated random field which is discretized using the Karhunen-Loève expansion. The spectral stochastic finite element method is used, with a polynomial chaos expansion to propagate uncertainties in the material characteristics to the response quantities. In continuum structures, either 2D or 3D random fields are modelled across the structural domain, while representation of the material uncertainties in linear truss elements is achieved by expanding 1D random fields along the length of the elements. Several examples demonstrate the method on both 2D and 3D continuum and truss structures, showing that this common framework provides an interesting insight into robustness versus optimality for the test problems considered.

  20. Structural design and static analysis of a double-ring deployable truss for mesh antennas

    NASA Astrophysics Data System (ADS)

    Xu, Yan; Guan, Fuling; Chen, Jianjun; Zheng, Yao

    2012-12-01

    This paper addresses the structural design, the deployment control design, the static analysis and the model testing of a new double-ring deployable truss that is intended for large mesh antennas. This deployable truss is a multi-DOF (degree-of-freedom), over-constrained mechanism. Two kinds of deployable basic elements were introduced, as well as a process to synthesise the structure of the deployable truss. The geometric equations were formulated to determine the length of each strut, including the effects of the joint size. A DOF evaluation showed that the mechanism requires two active cables and requires deployment control. An open-loop control system was designed to control the rotational velocities of two motors. The structural stiffness of the truss was assessed by static analysis that considered the effects of the constraint condition and the pre-stress of the passive cables. A 4.2-metre demonstration model of an antenna was designed and fabricated. The geometry and the deployment behaviour of the double-ring truss were validated by the experiments using this model.

  1. Research on the mechanical properties of a glass fiber reinforced polymer-steel combined truss structure.

    PubMed

    Liu, Pengfei; Zhao, Qilin; Li, Fei; Liu, Jinchun; Chen, Haosen

    2014-01-01

    An assembled plane truss structure used for vehicle loading is designed and manufactured. In the truss, the glass fiber reinforced polymer (GFRP) tube and the steel joint are connected by a new technology featuring a pretightened tooth connection. The detailed description for the rod and node design is introduced in this paper, and a typical truss panel is fabricated. Under natural conditions, the short-term load test and long-term mechanical performance test for one year are performed to analyze its performance and conduct a comparative analysis for a reasonable FEM model. The study shows that the design and fabrication for the node of an assembled truss panel are convenient, safe, and reliable; because of the creep control design of the rods, not only does the short-term structural stiffness meet the design requirement but also the long-term creep deformation tends towards stability. In addition, no significant change is found in the elastic modules, so this structure can be applied in actual engineering. Although the safety factor for the strength of the composite rods is very large, it has a lightweight advantage over the steel truss for the low density of GFRP. In the FEM model, simplifying the node as a hinge connection relatively conforms to the actual status. PMID:25247203

  2. Research on the Mechanical Properties of a Glass Fiber Reinforced Polymer-Steel Combined Truss Structure

    PubMed Central

    Liu, Pengfei; Zhao, Qilin; Li, Fei; Liu, Jinchun; Chen, Haosen

    2014-01-01

    An assembled plane truss structure used for vehicle loading is designed and manufactured. In the truss, the glass fiber reinforced polymer (GFRP) tube and the steel joint are connected by a new technology featuring a pretightened tooth connection. The detailed description for the rod and node design is introduced in this paper, and a typical truss panel is fabricated. Under natural conditions, the short-term load test and long-term mechanical performance test for one year are performed to analyze its performance and conduct a comparative analysis for a reasonable FEM model. The study shows that the design and fabrication for the node of an assembled truss panel are convenient, safe, and reliable; because of the creep control design of the rods, not only does the short-term structural stiffness meet the design requirement but also the long-term creep deformation tends towards stability. In addition, no significant change is found in the elastic modules, so this structure can be applied in actual engineering. Although the safety factor for the strength of the composite rods is very large, it has a lightweight advantage over the steel truss for the low density of GFRP. In the FEM model, simplifying the node as a hinge connection relatively conforms to the actual status. PMID:25247203

  3. Component mode synthesis and large deflection vibrations of complex structures. [beams and trusses

    NASA Technical Reports Server (NTRS)

    Mei, C.

    1984-01-01

    The accuracy of the NASTRAN modal synthesis analysis was assessed by comparing it with full structure NASTRAN and nine other modal synthesis results using a nine-bay truss. A NASTRAN component mode transient response analysis was also performed on the free-free truss structure. A finite element method was developed for nonlinear vibration of beam structures subjected to harmonic excitation. Longitudinal deformation and inertia are both included in the formula. Tables show the finite element free vibration results with and without considering the effects of longitudinal deformation and inertia as well as the frequency ratios for a simply supported and a clamped beam subjected to a uniform harmonic force.

  4. Damping Properties of Sandwich Truss Core Structures by Strain Energy Method

    NASA Astrophysics Data System (ADS)

    Wesolowski, M.; Rucevskis, S.; Janeliukstis, R.; Polanski, M.

    2015-11-01

    Sandwich panel structures with stiff face sheets and cellular cores are widely used to support dynamic loads. Combining face sheets made of carbon fibre reinforced plastics (CFRPs) with an aluminium pyramidal truss improves the damping performance of the structure due to viscoelastic character of CRFP composites. To predict the damping characteristics of the pyramidal truss core sandwich panel the strain energy method is adopted. The procedure for evaluating the damping of the sandwich panel was performed using commercial finite element software NASTRAN and MATLAB. Non-contact vibration tests were performed on the real sandwich panels in order to extract the modal characteristics and compare them with the numerical predictions.

  5. Optimal placement of semi-active joints in large-space truss structures

    NASA Astrophysics Data System (ADS)

    Wirnitzer, Jan; Kistner, A.; Gaul, Lothar

    2002-06-01

    The low structural damping of large space structures and the stringent positioning requirements in missions demand effective vibration suppression. The semi-active approach at hand is based on friction damping due to interfacial slip in semi-active joints which can be controlled by varying the normal pressure in the contact area using a piezo-disc actuator. This paper focuses on the optimal placement of semi-active joints for vibration suppression. The proposed method uses optimality criteria for actuator and sensor locations based on eigenvalues of the controllability and observability gramians. It is stated as a nonlinear multicriteria optimization problem with discrete variables which is solved by a stochastic search algorithm. As final step in the design procedure, parameters of the local feedback controllers assigned to each adaptive joint are optimized with respect to transient response of the structure. The present method is applied to a 10-bay truss structure. Simulation runs of the controlled structure are used to verify the optimization results.

  6. Structural optimization and model fabrication of a double-ring deployable antenna truss

    NASA Astrophysics Data System (ADS)

    Dai, Lu; Guan, Fuling; Guest, James K.

    2014-02-01

    This paper explores the design of a new type of deployable antenna system composed of a double-ring deployable truss, prestressed cable nets, and a metallic reflector mesh. The primary novelty is the double-ring deployable truss, which is found to significantly enhance the stiffness of the entire antenna over single-ring systems with relatively low mass gain. Structural optimization was used to minimize the system mass subject to constraints on system stiffness and member section availability. Both genetic algorithms (GA) and gradient-based optimizers are employed. The optimized system results were obtained and incorporated into a 4.2-m scaled system prototype, which was then experimentally tested for dynamic properties. Practical considerations such as the maximum number of truss sides and their effects on system performances were also discussed.

  7. Design, development and mechanization of a precision deployable truss with optimized structural efficiency for spaceborne applications

    NASA Technical Reports Server (NTRS)

    Craighead, N. D.; Hult, T. D.; Preliasco, R. J.

    1982-01-01

    A deployable mast concept which meets the weight, size and stability requirements for a feed support structure for offset antennas up to 100 meters in diameter is discussed. A triangulated truss configuration, the use of tapered tubes which exhibit a high strength-to-weight ratio, and low CTE graphite-epoxy material are seen to provide an efficient, lightweight and stable truss suitable for an antenna feed support. A low stowage ratio of 30:1 is achieved through a unique preloaded hinge located at the center of each longeron and an autonomous deployment cage with a drive mechanism. Initial analysis and proof of concept hardware validated the basic mechanism and design assumptions and provided a basis for further investigation. The concept can readily accept variations in member size and thus lends itself to optimization for other potential uses where a stiff, lightweight deployable truss is needed.

  8. Piezoelectric devices for vibration suppression: Modeling and application to a truss structure

    NASA Technical Reports Server (NTRS)

    Won, Chin C.; Sparks, Dean W., Jr.; Belvin, W. Keith; Sulla, Jeff L.

    1993-01-01

    For a space structure assembled from truss members, an effective way to control the structure may be to replace the regular truss elements by active members. The active members play the role of load carrying elements as well as actuators. A piezo strut, made of a stack of piezoceramics, may be an ideal active member to be integrated into a truss space structure. An electrically driven piezo strut generates a pair of forces, and is considered as a two-point actuator in contrast to a one-point actuator such as a thruster or a shaker. To achieve good structural vibration control, sensing signals compatible to the control actuators are desirable. A strain gage or a piezo film with proper signal conditioning to measure member strain or strain rate, respectively, are ideal control sensors for use with a piezo actuator. The Phase 0 CSI Evolutionary Model (CEM) at NASA Langley Research Center used cold air thrusters as actuators to control both rigid body motions and flexible body vibrations. For the Phase 1 and 2 CEM, it is proposed to use piezo struts to control the flexible modes and thrusters to control the rigid body modes. A tenbay truss structure with active piezo struts is built to study the modeling, controller designs, and experimental issues. In this paper, the tenbay structure with piezo active members is modelled using an energy method approach. Decentralized and centralized control schemes are designed and implemented, and preliminary analytical and experimental results are presented.

  9. Preliminary design of a large tetrahedral truss/hexagonal panel aerobrake structural system

    NASA Technical Reports Server (NTRS)

    Dorsey, John T.; Mikulas, Martin M., Jr.

    1990-01-01

    This paper introduces an aerobrake structural concept consisting of two primary components: (1) a lightweight erectable tetrahedral support truss, and (2) a heatshield composed of individual sandwich hexagonal panels which, when attached to the truss, function as a continuous aerobraking surface. A general preliminary analysis procedure to design the aerobrake components is developed, and values of the aerobrake design parameters which minimize the mass and packaging volume for a 120-foot-diameter aerobrake are determined. Sensitivity of the aerobrake design to variations in design parameters is also assessed.

  10. The effect of carbon plastic truss structures of solar arrays on dynamical characteristics of their drive mechanism

    NASA Astrophysics Data System (ADS)

    Shatikhin, V. Ye.; Semenov, L. P.; Artemenko, Yu. H.; Ihnatovych, S. R.

    We consider the effect of carbon plastic truss structures on dynamical characteristics of drive mechanism of space vehicle solar arrays. An analysis is made for frequencies of own oscillations of the truss structures of solar arrays and for dynamical characteristics of their drive mechanism for the case of structures from the carbon and plastic as well as from the aluminium alloy AMh-6. We substantiate the advantages of the manufacturing of truss structures of frameworks from the carbon and plastic by the winding method in respect of deriving a higher rigidity of a structure.

  11. Development of an active truss element for control of precision structures

    NASA Technical Reports Server (NTRS)

    Anderson, Eric H.; Moore, Donald M.; Fanson, James L.; Ealey, Mark A.

    1990-01-01

    An active structural element for use in precision control of large space structures is described. The active member is intended to replace a passive strut in a truss-like structure. It incorporates an eddy current displacement sensor and an actuator that is either piezoelectric (PZT) or electrostrictive (PMN). The design of the device is summarized. Performance of separate PZT and PMN actuators is compared for several properties relevant to submicrometer control of precision structures.

  12. Control of resonant frequencies in adaptive structures by prestressing

    NASA Technical Reports Server (NTRS)

    Baycan, Can M.; Utku, Senol; Wada, Ben K.

    1992-01-01

    The natural vibration frequencies of a structure can be affected by inducing stress in the structure. The success of this kind of control of the resonant frequencies of a truss structure depends on the geometry of the structure. It is shown that in adaptive truss structures the method is effective for vibrations in less stiff directions, such as the normal direction of the plane containing all of the bars of a node, suggesting its applicability for cable, membrane, and thin plate and shell structures.

  13. The use of composite trusses in long-span power plant structures

    SciTech Connect

    Ryan, J.L.

    1996-10-01

    With the current global competition for large-scale, lump-sum, design-build construction projects, the American design engineer must consistently strive for lowest total installed cost in the country in which the project is constructed. In a building recently constructed in Saudi Arabia as part of a $500 million power plant project, long-span composite trusses were used, with significant steel savings and overall cost savings. While composite beams are used throughout the commercial and industrial building sectors, composite trusses are typically not beneficial in the US due to the high fabrication costs associated with the system. However, in many foreign countries, steel material costs are multiples of those in the US, while fabrication and erection costs are a fraction of those in the US. Thus, in certain cases significant savings can be realized by expanding the engineering paradigms to use unconventional systems. This paper summarizes, for a specific 21-meter span composite truss application, the building framing evaluation, composite truss design methodology, and benefits achieved. In the particular case cited, structural savings were nominally 50% of the cost of the alternate systems of structural joists and conventional composite beams.

  14. Structural performance of a hybrid FRP-aluminum modular triangular Truss system subjected to various loading conditions.

    PubMed

    Zhang, Dongdong; Huang, Yaxin; Zhao, Qilin; Li, Fei; Li, Feng; Gao, Yifeng

    2014-01-01

    A novel hybrid FRP-aluminum truss system has been employed in a two-rut modular bridge superstructure composed of twin inverted triangular trusses. The actual flexural behavior of a one-rut truss has been previously investigated under the on-axis loading test; however, the structural performance of the one-rut truss subjected to an off-axis load is still not fully understood. In this paper, a geometrical linear finite element model is introduced and validated by the on-axis loading test; the structural performance of the one-rut truss subjected to off-axis load was numerically obtained; the dissimilarities of the structural performance between the two different loading cases are investigated in detail. The results indicated that (1) the structural behavior of the off-axis load differs from that of the on-axis load, and the off-axis load is the critical loading condition controlling the structural performance of the triangular truss; (2) under the off-axis load, the FRP trussed members and connectors bear certain out-of-plane bending moments and are subjected to a complicated stress state; and (3) the stress state of these members does not match that of the initial design, and optimization for the redesign of these members is needed, especially for the pretightened teeth connectors. PMID:25254254

  15. Structural Performance of a Hybrid FRP-Aluminum Modular Triangular Truss System Subjected to Various Loading Conditions

    PubMed Central

    Zhang, Dongdong; Huang, Yaxin; Zhao, Qilin; Li, Fei; Gao, Yifeng

    2014-01-01

    A novel hybrid FRP-aluminum truss system has been employed in a two-rut modular bridge superstructure composed of twin inverted triangular trusses. The actual flexural behavior of a one-rut truss has been previously investigated under the on-axis loading test; however, the structural performance of the one-rut truss subjected to an off-axis load is still not fully understood. In this paper, a geometrical linear finite element model is introduced and validated by the on-axis loading test; the structural performance of the one-rut truss subjected to off-axis load was numerically obtained; the dissimilarities of the structural performance between the two different loading cases are investigated in detail. The results indicated that (1) the structural behavior of the off-axis load differs from that of the on-axis load, and the off-axis load is the critical loading condition controlling the structural performance of the triangular truss; (2) under the off-axis load, the FRP trussed members and connectors bear certain out-of-plane bending moments and are subjected to a complicated stress state; and (3) the stress state of these members does not match that of the initial design, and optimization for the redesign of these members is needed, especially for the pretightened teeth connectors. PMID:25254254

  16. Vibration suppression control of smart piezoelectric rotating truss structure by parallel neuro-fuzzy control with genetic algorithm tuning

    NASA Astrophysics Data System (ADS)

    Lin, J.; Zheng, Y. B.

    2012-07-01

    The main goal of this paper is to develop a novel approach for vibration control on a piezoelectric rotating truss structure. This study will analyze the dynamics and control of a flexible structure system with multiple degrees of freedom, represented in this research as a clamped-free-free-free truss type plate rotated by motors. The controller has two separate feedback loops for tracking and damping, and the vibration suppression controller is independent of position tracking control. In addition to stabilizing the actual system, the proposed proportional-derivative (PD) control, based on genetic algorithm (GA) to seek the primary optimal control gain, must supplement a fuzzy control law to ensure a stable nonlinear system. This is done by using an intelligent fuzzy controller based on adaptive neuro-fuzzy inference system (ANFIS) with GA tuning to increase the efficiency of fuzzy control. The PD controller, in its assisting role, easily stabilized the linear system. The fuzzy controller rule base was then constructed based on PD performance-related knowledge. Experimental validation for such a structure demonstrates the effectiveness of the proposed controller. The broad range of problems discussed in this research will be found useful in civil, mechanical, and aerospace engineering, for flexible structures with multiple degree-of-freedom motion.

  17. Probabilistic progressive buckling of trusses

    NASA Technical Reports Server (NTRS)

    Pai, Shantaram S.; Chamis, Christos C.

    1991-01-01

    A three-bay, space, cantilever truss is probabilistically evaluated to describe progressive buckling and truss collapse in view of the numerous uncertainties associated with the structural, material, and load variables (primitive variables) that describe the truss. Initially, the truss is deterministically analyzed for member forces, and member(s) in which the axial force exceeds the Euler buckling load are identified. These member(s) are then discretized with several intermediate nodes and a probabilistic buckling analysis is performed on the truss to obtain its probabilistic buckling loads and respective mode shapes. Furthermore, sensitivities associated with the uncertainties in the primitive variables are investigated, margin of safety values for the truss are determined, and truss end node displacements are noted. These steps are repeated by sequentially removing the buckled member(s) until onset of truss collapse is reached. Results show that this procedure yields an optimum truss configuration for a given loading and for a specified reliability.

  18. Structural analysis of three space crane articulated-truss joint concepts

    NASA Technical Reports Server (NTRS)

    Wu, K. Chauncey; Sutter, Thomas R.

    1992-01-01

    Three space crane articulated truss joint concepts are studied to evaluate their static structural performance over a range of geometric design parameters. Emphasis is placed on maintaining the four longeron reference truss performance across the joint while allowing large angle articulation. A maximum positive articulation angle and the actuator length ratio required to reach the angle are computed for each concept as the design parameters are varied. Configurations with a maximum articulation angle less than 120 degrees or actuators requiring a length ratio over two are not considered. Tip rotation and lateral deflection of a truss beam with an articulated truss joint at the midspan are used to select a point design for each concept. Deflections for one point design are up to 40 percent higher than for the other two designs. Dynamic performance of the three point design is computed as a function of joint articulation angle. The two lowest frequencies of each point design are relatively insensitive to large variations in joint articulation angle. One point design has a higher maximum tip velocity for the emergency stop than the other designs.

  19. Aeroelasticity of Axially Loaded Aerodynamic Structures for Truss-Braced Wing Aircraft

    NASA Technical Reports Server (NTRS)

    Nguyen, Nhan; Ting, Eric; Lebofsky, Sonia

    2015-01-01

    This paper presents an aeroelastic finite-element formulation for axially loaded aerodynamic structures. The presence of axial loading causes the bending and torsional sitffnesses to change. For aircraft with axially loaded structures such as the truss-braced wing aircraft, the aeroelastic behaviors of such structures are nonlinear and depend on the aerodynamic loading exerted on these structures. Under axial strain, a tensile force is created which can influence the stiffness of the overall aircraft structure. This tension stiffening is a geometric nonlinear effect that needs to be captured in aeroelastic analyses to better understand the behaviors of these types of aircraft structures. A frequency analysis of a rotating blade structure is performed to demonstrate the analytical method. A flutter analysis of a truss-braced wing aircraft is performed to analyze the effect of geometric nonlinear effect of tension stiffening on the flutter speed. The results show that the geometric nonlinear tension stiffening effect can have a significant impact on the flutter speed prediction. In general, increased wing loading results in an increase in the flutter speed. The study illustrates the importance of accounting for the geometric nonlinear tension stiffening effect in analyzing the truss-braced wing aircraft.

  20. Ultrasonic guided waves for nondestructive evaluation/structural health monitoring of trusses

    NASA Astrophysics Data System (ADS)

    'Peter'Zhu, Xuan; Rizzo, Piervincenzo; Marzani, Alessandro; Bruck, Jerry

    2010-04-01

    Ultrasonic guided waves (UGWs) are particularly effective in those nondestructive evaluation and structural health monitoring applications that benefit from built-in transduction, moderately large inspection ranges and high sensitivity to small flaws. This paper describes a method to detect cracks in large trusses that combines the advantages of UGWs with the extraction of defect-sensitive features to perform a multivariate diagnosis of damage. The proposed algorithm was applied to the guided waves propagating along one of the main chords of a dismantled overhead sign support structure. The probing hardware consisted of a data acquisition system that controlled the generation and detection of ultrasonic signals by means of piezoelectric transducers made of lead zirconate titanate. The effectiveness of the proposed approach to diagnose the presence of an artificial defect around the welded joint between one main chord and a diagonal member of the truss structure is explained.

  1. Structural damage detection of space truss structures using best achievable eigenvectors

    NASA Technical Reports Server (NTRS)

    Lim, Tae W.; Kashangaki, Thomas A. L.

    1994-01-01

    A method is presented by which measured modes and frequencies from a modal test can be used to determine the location and magnitude of damage in a space struss structure. The damage is located by computing the Euclidean distances between the measured mode shapes and the best achievable eigenvectors. The best achievable eigenvectors are the projection of the measured mode shapes onto the subspace defined by the refined analytical model of the structure and the measured frequencies. Loss of both stiffness and mass properties can be located and quantified. To examine the performance of the method when experimentally measured modes are employed, various damage detection studies using a laboratory eight-bay truss structure were conducted. The method performs well even though the measurement errors inevitably make the damage location more difficult.

  2. A peridynamic model for the nonlinear static analysis of truss and tensegrity structures

    NASA Astrophysics Data System (ADS)

    Li, Hui; Zhang, Hongwu; Zheng, Yonggang; Zhang, Liang

    2016-05-01

    A peridynamic model is developed in this paper for the nonlinear static analysis of truss and tensegrity structures. In the present model, the motion equations of material points are established on the current configuration and the pairwise forces are functions of extension and direction of the bonds. The peridynamic parameters are obtained based on the equivalence between the strain energy densities of the peridynamic and classical continuum models. The present model is applied to the mechanical analysis of bimodular truss and tensegrity structures, in which the compressive modulus is set to be zero for the cables. Several representative examples are carried out and the results verify the validity and efficiency of the developed model by comparing with the conventional nonlinear finite element method.

  3. Artificial intelligence approach to planning the robotic assembly of large tetrahedral truss structures

    NASA Technical Reports Server (NTRS)

    Homemdemello, Luiz S.

    1992-01-01

    An assembly planner for tetrahedral truss structures is presented. To overcome the difficulties due to the large number of parts, the planner exploits the simplicity and uniformity of the shapes of the parts and the regularity of their interconnection. The planning automation is based on the computational formalism known as production system. The global data base consists of a hexagonal grid representation of the truss structure. This representation captures the regularity of tetrahedral truss structures and their multiple hierarchies. It maps into quadratic grids and can be implemented in a computer by using a two-dimensional array data structure. By maintaining the multiple hierarchies explicitly in the model, the choice of a particular hierarchy is only made when needed, thus allowing a more informed decision. Furthermore, testing the preconditions of the production rules is simple because the patterned way in which the struts are interconnected is incorporated into the topology of the hexagonal grid. A directed graph representation of assembly sequences allows the use of both graph search and backtracking control strategies.

  4. Component count and preliminary assembly considerations for large space truss structures

    NASA Technical Reports Server (NTRS)

    Kenner, W. Scott; Rhodes, Marvin D.; Fichter, W. B.

    1990-01-01

    Expressions for the number of truss components per truss division are presented along with expressions for the area and dimensions of mosaic hexagonal panel arrangements. The expressions were developed by substituting the number of truss components in specific truss divisions into associated polynomial equations and solving for the coefficients of the polynomials. To assist in automated or astronaut truss/panel assembly operations, a concept for assembling a tetrahedral truss with hexagonal panels is presented. The assembly concept minimizes the exchange of truss assembly devices and panel attachment devices, assuming that the number of exchanges is a driving assembly concern.

  5. A smart end-effector for assembly of space truss structures

    NASA Technical Reports Server (NTRS)

    Doggett, William R.; Rhodes, Marvin D.; Wise, Marion A.; Armistead, Maurice F.

    1992-01-01

    A unique facility, the Automated Structures Research Laboratory, is being used to investigate robotic assembly of truss structures. A special-purpose end-effector is used to assemble structural elements into an eight meter diameter structure. To expand the capabilities of the facility to include construction of structures with curved surfaces from straight structural elements of different lengths, a new end-effector has been designed and fabricated. This end-effector contains an integrated microprocessor to monitor actuator operations through sensor feedback. This paper provides an overview of the automated assembly tasks required by this end-effector and a description of the new end-effector's hardware and control software.

  6. Breaking wave impact forces on truss support structures for offshore wind turbines

    NASA Astrophysics Data System (ADS)

    Cieślikiewicz, Witold; Gudmestad, Ove T.; Podrażka, Olga

    2014-05-01

    Due to depletion of the conventional energy sources, wind energy is becoming more popular these days. Wind energy is being produced mostly from onshore farms, but there is a clear tendency to transfer wind farms to the sea. The foundations of offshore wind turbines may be truss structures and might be located in shallow water, where are subjected to highly varying hydrodynamic loads, particularly from plunging breaking waves. There are models for impact forces prediction on monopiles. Typically the total wave force on slender pile from breaking waves is a superposition of slowly varying quasi-static force, calculated from the Morison equation and additional dynamical, short duration force due to the impact of the breaker front or breaker tongue. There is not much research done on the truss structures of wind turbines and there are still uncertainties on slamming wave forces, due to plunging breaking waves on those structures. Within the WaveSlam (Wave slamming forces on truss structures in shallow water) project the large scale tests were carried out in 2013 at the Large Wave Flume in Forschungszentrum Küste (FZK) in Hannover, Germany. The following institutions participated in this initiative: the University of Stavanger and the Norwegian University of Science and Technology (project management), University of Gdańsk, Poland, Hamburg University of Technology and the University of Rostock, Germany and Reinertsen AS, Norway. This work was supported by the EU 7th Framework Programme through the grant to the budget of the Integrating Activity HYDRALAB IV. The main aim of the experiment was to investigate the wave slamming forces on truss structures, development of new and improvement of existing methods to calculate forces from the plunging breakers. The majority of the measurements were carried out for regular waves with specified frequencies and wave heights as well as for the irregular waves based on JONSWAP spectrum. The truss structure was equipped with both

  7. Structural efficiency of long lightly loaded truss and isogrid columns for space applications

    NASA Technical Reports Server (NTRS)

    Mikulas, M. M., Jr.

    1978-01-01

    The general mass characteristics of long lightly loaded columns for space applications are investigated by studying four column concepts. The first is a simple tubular column, the second is a three longeron truss column constructed of tubular members, the third is a three longeron truss column constructed of solid rod members, and the fourth is an open grid work isogrid wall tubular column. Design procedures, which include an initial imperfection in the straightness of the column, are developed for the different concepts and demonstrated numerically. A new set of structural efficiency parameters are developed for lightly loaded columns and are used to show a comparison of the masses of the four column concepts investigated.

  8. Structural Aspects of Railway Truss Bridges Affecting Transverse Shear Forces in Steel-Concrete Composite Decks

    NASA Astrophysics Data System (ADS)

    Siekierski, Wojciech

    2015-03-01

    At the steel-concrete interface, the horizontal shear forces that are transverse to cross beams occur due to joint action of the steel-concrete composite deck and the truss girders. Numerical analysis showed that values of the forces are big in comparison to the longitudinal shear forces. In both cases extreme force values occur near side edges of a slab. The paper studies possibilities of reduction of these shear forces by structural alterations of the following: rigidity of a concrete slab, arrangement of a wind bracing, arrangement of concrete slab expansion joints. An existing railway truss bridge span has been analysed. Numerical analysis shows that it is possible to reduce the values of shear forces transverse to cross beams. It may reach 20% near the side edges of slabs and 23% in the centre of slab width.

  9. Baseline tests of an autonomous telerobotic system for assembly of space truss structures

    NASA Technical Reports Server (NTRS)

    Rhodes, Marvin D.; Will, Ralph W.; Quach, Coung

    1994-01-01

    Several proposed space missions include precision reflectors that are larger in diameter than any current or proposed launch vehicle. Most of these reflectors will require a truss structure to accurately position the reflector panels and these reflectors will likely require assembly in orbit. A research program has been conducted at the NASA Langley Research Center to develop the technology required for the robotic assembly of truss structures. The focus of this research has been on hardware concepts, computer software control systems, and operator interfaces necessary to perform supervised autonomous assembly. A special facility was developed and four assembly and disassembly tests of a 102-strut tetrahedral truss have been conducted. The test procedures were developed around traditional 'pick-and-place' robotic techniques that rely on positioning repeatability for successful operation. The data from two of the four tests were evaluated and are presented in this report. All operations in the tests were controlled by predefined sequences stored in a command file, and the operator intervened only when the system paused because of the failure of an actuator command. The tests were successful in identifying potential pitfalls in a telerobotic system, many of which would not have been readily anticipated or incurred through simulation studies. Addressing the total integrated task, instead of bench testing the component parts, forced all aspects of the task to be evaluated. Although the test results indicate that additional developments should be pursued, no problems were encountered that would preclude automated assembly in space as a viable construction method.

  10. Real-time control of geometry and stiffness in adaptive structures

    NASA Technical Reports Server (NTRS)

    Ramesh, A. V.; Utku, S.; Wada, B. K.

    1991-01-01

    The basic theory is presented for the geometry, stiffness, and damping control of adaptive structures, with emphasis on adaptive truss structures. Necessary and sufficient conditions are given for stress-free geometry control in statically determinate and indeterminate adaptive discrete structures. Two criteria for selecting the controls are proposed, and their use in real-time control is illustrated by numerical simulation results. It is shown that the stiffness and damping control of adaptive truss structures for vibration suppression is possible by elongation and elongation rate dependent feedback forces from the active elements.

  11. Design and analysis of the glass fiber composite truss beam structure

    NASA Astrophysics Data System (ADS)

    Chen, Lina; Li, Zhi

    2015-07-01

    To exert the corrosion-resistant characteristics of the composite materials, which have overcome the characteristics of low modulus of the truss structure design. We designed a new kind of beam-slab structure and it can be applied to the desulfurization and denitration tower. The kingpost is undertook by four successive FRP profiles and nodes connected by hough; both ends are connected by a rod with the thread structure. This research analyzed the structure of the finite element, and the result comes out that the stress, the strain and distortion of the whole kingpost, are meet regulatory requirements as well.

  12. Finite element modeling of truss structures with frequency-dependent material damping

    NASA Technical Reports Server (NTRS)

    Lesieutre, George A.

    1991-01-01

    A physically motivated modelling technique for structural dynamic analysis that accommodates frequency dependent material damping was developed. Key features of the technique are the introduction of augmenting thermodynamic fields (AFT) to interact with the usual mechanical displacement field, and the treatment of the resulting coupled governing equations using finite element analysis methods. The AFT method is fully compatible with current structural finite element analysis techniques. The method is demonstrated in the dynamic analysis of a 10-bay planar truss structure, a structure representative of those contemplated for use in future space systems.

  13. Topology structure synthesis and analysis of spatial pyramid deployable truss structures for satellite SAR antenna

    NASA Astrophysics Data System (ADS)

    Wang, Yan; Deng, Zongquan; Liu, Rongqiang; Yang, Hui; Guo, Hongwei

    2014-07-01

    Many attentions for structural synthesis are paid to planar linkages and parallel mechanisms, while design novel pyramid deployable truss structure(PDTS) of satellite SAR mainly depends on experience of designer. To design novel configuration of PDTS, a two-step topology structure synthesis and analysis approach is proposed. Firstly, a conceptual configuration of PDTS is synthesized. Weighted graph and weighted adjacency matrix are established to realize topological description for PDTS. Graph properties are then summarized to distinguish differentia between PDTS and other type structures. According to graph properties, a procedure for synthesis conceptual configuration of PDTS is presented. Secondly, join relationship of components in a PDTS is analyzed. Kinematic chain and corresponding incidence/adjacency matrix are employed to analyze join relationship of PDTS. Properties and simplified rules of kinematic chain are extracted to construct kinematic chain. A procedure for construction kinematic chain of PDTS is then established. Finally, with this two-step approach all 11 rectangular pyramid deployable structures whose folded state is planar are discovered and their kinematic chains are constructed. Based on synthesis results, a novel deployable support structure for satellite SAR is designed. The proposed research can be applied to obtain some novel PDTSs, which is of great importance to design some novel deployable support structures for satellite SAR antenna.

  14. Synchronously deployable double fold beam and planar truss structure

    NASA Technical Reports Server (NTRS)

    Rhodes, Marvin D. (Inventor); Hedgepeth, John M. (Inventor)

    1991-01-01

    A deployable structure that synchronously deploys in both length and width is disclosed which is suitable for use as a structural component for orbiting space stations or large satellites. The structure is designed with maximum packing efficiency so that large structures may be collapsed and transported in the cargo bay of the Space Shuttle. The synchronous deployment feature allows the structure to be easily deployed in space by two astronauts, without a complex deployment mechanism. The structure is made up of interconnected structural units, each generally in the shape of a parallelepiped. The structural units are constructed of structural members connected with hinged and fixed connections at connection nodes in each corner of the parallelepiped. Diagonal members along each face of the parallelepiped provide structural rigidity and are equipped with mid-length, self-locking hinges to allow the structure to collapse. The structure is designed so that all hinged connections may be made with simple clevis-type hinges requiring only a single degree of freedom, and each hinge pin is located along the centerline of its structural member for increased strength and stiffness.

  15. SEISMIC UPGRADE EFFECT OF STEEL TRUSS STRUCTURES WITH H-SECTION BRBS

    NASA Astrophysics Data System (ADS)

    Funayama, Junki; Imase, Fumiaki; Usami, Tsutomu; Wang, Chun-Lin

    This paper presents a result of a series of general investigations into the seismic upgrading of steel bridge structures. To this end, one of the most efficient ways is found to install energy dissipation devices in bridges, such as buckling-restrained braces (BRBs). An idea of installing BRBs in existing bridges is to wrap existing brace members by a sort of buckling restraining members so that the overall buckling of the braces would not occur. In this paper five test specimens of truss structures with and without BRBs in the diagonal members are tested under monotonic and cyclic loadings, and the seismic upgrading due to BRBs is verified.

  16. Optimal decentralized feedback control for a truss structure

    NASA Technical Reports Server (NTRS)

    Cagle, A.; Ozguner, U.

    1989-01-01

    One approach to the decentralized control of large flexible space structures involves the design of controllers for the substructures of large systems and their subsequent application to the entire coupled system. This approach is presently developed for the case of active vibration damping on an experimental large struss structure. The isolated boundary loading method is used to define component models by FEM; component controllers are designed using an interlocking control concept which minimizes the motion of the boundary nodes, thereby reducing the exchange of mechanical disturbances among components.

  17. Optimal placement of tuning masses on truss structures by genetic algorithms

    NASA Technical Reports Server (NTRS)

    Ponslet, Eric; Haftka, Raphael T.; Cudney, Harley H.

    1993-01-01

    Optimal placement of tuning masses, actuators and other peripherals on large space structures is a combinatorial optimization problem. This paper surveys several techniques for solving this problem. The genetic algorithm approach to the solution of the placement problem is described in detail. An example of minimizing the difference between the two lowest frequencies of a laboratory truss by adding tuning masses is used for demonstrating some of the advantages of genetic algorithms. The relative efficiencies of different codings are compared using the results of a large number of optimization runs.

  18. A modal test of a space-truss for structural parameter identification

    SciTech Connect

    Carne, T.G.; Mayes, R.L.; Levine-West, M.B.

    1992-12-01

    The Jet Propulsion Laboratory is developing a large space-truss to support a micro-precision interferometer. A finite element model will be used to design and place passive and active elements in the truss to suppress vibration. To improve the model`s predictive capability, it is desirable to identify uncertain structural parameters in the model by utilizing experimental modal data. Testing of both the components and the system was performed to obtain the data necessary to identify the structural parameters. Extracting a modal model, absent of bias errors, from measured data requires great care in test design and implementation. Testing procedures that are discussed include: verification of non-constraining shaker attachment, quantification of the non-linear structural response, and the design and effects of suspension systems used to simulate a free structure. In addition to these procedures, the accuracy of the measured frequency response functions are evaluated by comparing functions measured with random excitation, using various frequency resolutions, and with step sine excitation.

  19. A modal test of a space-truss for structural parameter identification

    SciTech Connect

    Carne, T.G.; Mayes, R.L. ); Levine-West, M.B. )

    1992-01-01

    The Jet Propulsion Laboratory is developing a large space-truss to support a micro-precision interferometer. A finite element model will be used to design and place passive and active elements in the truss to suppress vibration. To improve the model's predictive capability, it is desirable to identify uncertain structural parameters in the model by utilizing experimental modal data. Testing of both the components and the system was performed to obtain the data necessary to identify the structural parameters. Extracting a modal model, absent of bias errors, from measured data requires great care in test design and implementation. Testing procedures that are discussed include: verification of non-constraining shaker attachment, quantification of the non-linear structural response, and the design and effects of suspension systems used to simulate a free structure. In addition to these procedures, the accuracy of the measured frequency response functions are evaluated by comparing functions measured with random excitation, using various frequency resolutions, and with step sine excitation.

  20. Weight optimization of large span steel truss structures with genetic algorithm

    SciTech Connect

    Mojolic, Cristian; Hulea, Radu; Pârv, Bianca Roxana

    2015-03-10

    The paper presents the weight optimization process of the main steel truss that supports the Slatina Sport Hall roof. The structure was loaded with self-weight, dead loads, live loads, snow, wind and temperature, grouped in eleven load cases. The optimization of the structure was made using genetic algorithms implemented in a Matlab code. A total number of four different cases were taken into consideration when trying to determine the lowest weight of the structure, depending on the types of connections with the concrete structure ( types of supports, bearing modes), and the possibility of the lower truss chord nodes to change their vertical position. A number of restrictions for tension, maximum displacement and buckling were enforced on the elements, and the cross sections are chosen by the program from a user data base. The results in each of the four cases were analyzed in terms of weight, element tension, element section and displacement. The paper presents the optimization process and the conclusions drawn.

  1. Underlying modal data issues for detecting damage in truss structures

    NASA Technical Reports Server (NTRS)

    Kashangaki, Thomas A-L.; Smith, Suzanne Weaver; Lim, Tae W.

    1992-01-01

    Independent of the modal identification techniques employed for damage detection, use of measured modal data limits the expectations for damage location. These limitations are examined using the distribution of modal strain energy and the sensitivity of the frequency and mode shapes to structural stiffness changes. For given measured modal information of specific accuracy, this examination reveals the following: (1) damage detection is feasible for members that contribute significantly to the strain energy of the measured modes, (2) the modes which are most effective in detecting damage to certain critical members can be identified, and (3) a relationship can be drawn between the accuracy of the measured modes and frequencies and damage detection feasibility.

  2. Modeling and simulation of an amplified structural damping system in a seismically-excited truss tower

    NASA Astrophysics Data System (ADS)

    Walsh, Kenneth K.; Cronin, Kyle J.; Rambo-Roddenberry, Michelle D.; Grupenhof, Kyle

    2010-04-01

    In the present work, numerical simulations are carried out to investigate a passive amplified structural damping system, the scissor-jack damper, for controlling vibrations in a seismically-excited truss tower. To reduce computational effort, a bi-model method is employed to represent the 3D truss tower as a dynamically equivalent 2D lumped-mass model. For the scissor-jack damper, a new formulation for the amplification factor equation of the device is presented, and then validated using CAD. The new formulation accounts for the large deformations experienced by the device as a result of the large displacements present in the flexible tower during seismic loading. In order to capture the interaction between the structure and control device, the displacement-dependent amplification factors of the scissor-jack devices, and velocity-dependent forces of the dampers, are calculated at each time step. The resulting amplified damper force is then applied back to the structure to determine its response at the next time step. The response of the tower with scissor-jack damper systems is simulated for the El Centro and Northridge earthquakes, and time-histories of the displacement and absolute acceleration at each level of the tower are obtained. These results indicate that the system is effective in reducing overall response of the tower without exceeding practical limits on the stroke capacity of the scissor-jack dampers.

  3. Synthesis and mechanical evaluation of micro-scale truss structures formed from self-propagating polymer waveguides

    NASA Astrophysics Data System (ADS)

    Jacobsen, Alan J.

    2007-12-01

    Materials with significant porosity, generally termed cellular materials, have considerably lower bulk density than their solid counterparts. However, at the cost of reducing the mass of a material by introducing porosity, mechanical properties such as the strength and elastic modulus are significantly diminished. Ordered cellular structures generally exhibit an increase in modulus and peak strength relative to random cellular configurations by changing the mode of deformation from bending-dominated to stretch/compression-dominated within the microstructure during elastic loading. Nevertheless, techniques to fabricate three-dimensional ordered open-cellular materials, particularly with feature sizes ranging from tens to hundred of microns, are limited. Presented in this dissertation, is a new technique to create cellular materials with a truss architecture from a three-dimensional interconnected pattern of self-propagating polymer waveguides. The self-propagating effect enables the rapid formation (< 1 min) of thick (> 5 mm) three-dimensional open-cellular micro-truss structures from a single two-dimensional exposure surface. The process also affords significant flexibility and control of the resulting truss microstructure. The structure-property relationships in these new polymer micro-trusses have been investigated, correlating compressive and shear behavior with structural features, such as density, cell size, truss angle, and unit cell architecture. The compression and shear modulus compare well with analytical predictions; however the measured peak strength was significantly lower than predicted. The deviation of the measured peak strength from the idealized predictions was attributed to imperfections in the structure and the nonlinear behavior of the solid polymer. The affect of imperfections can be reduced by developing unit cell architectures with increased waveguide connectivity that ultimately increase nodal stability and decrease the waveguide truss

  4. Adaptive structures to meet future requirements for large precision structures

    NASA Technical Reports Server (NTRS)

    Wada, B. K.; Fanson, J. L.; Garba, J. A.; Chen, G.-S.

    1989-01-01

    The role of adaptive structures in meeting the structural requirements for future NASA missions is described. Many of NASA's future missions require large precision truss type structures where prespecified locations on the structure must maintain micron level accuracies with respect to each other when subjected to manufacturing errors and static, thermal, and dynamic inputs. In many cases the incorporation of the adaptive structures concepts into the structural design to adjust the on-orbit structure will be the only feasible means to attain the desired accuracies. In order for the structures to be able to change structural characteristics on orbit they must be uncoupled and independent of the control system used to impart the required rigid body motion to the spacecraft.

  5. Evaluation of chromic acid anodized aluminum foil coated composite tubes for the Space Station truss structure

    NASA Technical Reports Server (NTRS)

    Dursch, Harry W.; Slemp, Wayne S.

    1988-01-01

    This paper describes the development and evaluation of chromic acid anodized (CAA) Al foil as a protective and thermal control coating for graphite/epoxy tubes designed for the Space Station truss structure. Special consideration is given to the development of solar-absorptance and thermal-emittance properties required of Al foil, the development of CAA parameters necessary to achieve these optical properties, and the atomic oxygen and UV testing of CAA Al foil. Results showed that 0.003-in CAA Al foil cocured or secondary bonded to graphite/epoxy tubes with thin epoxy film adhesive retains excellent bond strength and provides a superior protective and thermal control coating to the LEO environment. Processes were developed for CAA Al foils long enough to continuously wrap the 23-ft-long diagonal struts of the Space Station truss structure. Specifications are presented for the processes of chromic acid anodizing of Al foil and for the bonding of anodized Al foil to graphite/epoxy tubes.

  6. Robotic Assembly of Truss Structures for Space Systems and Future Research Plans

    NASA Technical Reports Server (NTRS)

    Doggett, William

    2002-01-01

    Many initiatives under study by both the space science and earth science communities require large space systems, i.e. with apertures greater than 15 m or dimensions greater than 20 m. This paper reviews the effort in NASA Langley Research Center's Automated Structural Assembly Laboratory which laid the foundations for robotic construction of these systems. In the Automated Structural Assembly Laboratory reliable autonomous assembly and disassembly of an 8 meter planar structure composed of 102 truss elements covered by 12 panels was demonstrated. The paper reviews the hardware and software design philosophy which led to reliable operation during weeks of near continuous testing. Special attention is given to highlight the features enhancing assembly reliability.

  7. Buckling tests of structural elements applicable to large erectable space trusses

    NASA Technical Reports Server (NTRS)

    Heard, W. L., Jr.; Bush, H. G.; Agranoff, N.

    1978-01-01

    Detailed data on columns and center a joint for completeness is presented. Buckling data for a tripod arrangement of these columns using a cluster joint is also presented. The objectives of these test are: (1) to gain insight into joint requirements for truss structure; (2) to assess the structural qualities of the column and center joint designs; (3) to investigate the restraint provided by octetruss core members (tripod) to the cluster joints; (4) to provide insight into the level of analysis required to predict buckling behavior of Gr/E nestable columns both as simple columns and in a tripod arrangement; and (5) to provide a data base for Gr/E nestable columns.

  8. Continuum modeling of three-dimensional truss-like space structures

    NASA Technical Reports Server (NTRS)

    Nayfeh, A. H.; Hefzy, M. S.

    1978-01-01

    A mathematical and computational analysis capability has been developed for calculating the effective mechanical properties of three-dimensional periodic truss-like structures. Two models are studied in detail. The first, called the octetruss model, is a three-dimensional extension of a two-dimensional model, and the second is a cubic model. Symmetry considerations are employed as a first step to show that the specific octetruss model has four independent constants and that the cubic model has two. The actual values of these constants are determined by averaging the contributions of each rod element to the overall structure stiffness. The individual rod member contribution to the overall stiffness is obtained by a three-dimensional coordinate transformation. The analysis shows that the effective three-dimensional elastic properties of both models are relatively close to each other.

  9. Design, fabrication and test of graphite/epoxy metering truss structure components, phase 3

    NASA Technical Reports Server (NTRS)

    1974-01-01

    The design, materials, tooling, manufacturing processes, quality control, test procedures, and results associated with the fabrication and test of graphite/epoxy metering truss structure components exhibiting a near zero coefficient of thermal expansion are described. Analytical methods were utilized, with the aid of a computer program, to define the most efficient laminate configurations in terms of thermal behavior and structural requirements. This was followed by an extensive material characterization and selection program, conducted for several graphite/graphite/hybrid laminate systems to obtain experimental data in support of the analytical predictions. Mechanical property tests as well as the coefficient of thermal expansion tests were run on each laminate under study, the results of which were used as the selection criteria for the single most promising laminate. Further coefficient of thermal expansion measurement was successfully performed on three subcomponent tubes utilizing the selected laminate.

  10. An expert system executive for automated assembly of large space truss structures

    NASA Technical Reports Server (NTRS)

    Allen, Cheryl L.

    1993-01-01

    Langley Research Center developed a unique test bed for investigating the practical problems associated with the assembly of large space truss structures using robotic manipulators. The test bed is the result of an interdisciplinary effort that encompasses the full spectrum of assembly problems - from the design of mechanisms to the development of software. The automated structures assembly test bed and its operation are described, the expert system executive and its development are detailed, and the planned system evolution is discussed. Emphasis is on the expert system implementation of the program executive. The executive program must direct and reliably perform complex assembly tasks with the flexibility to recover from realistic system errors. The employment of an expert system permits information that pertains to the operation of the system to be encapsulated concisely within a knowledge base. This consolidation substantially reduced code, increased flexibility, eased software upgrades, and realized a savings in software maintenance costs.

  11. Deployment of a Curved Truss

    NASA Technical Reports Server (NTRS)

    Giersch, Louis R.; Knarr, Kevin

    2010-01-01

    Structures capable of deployment into complex, three-dimensional trusses have well known space technology applications such as the support of spacecraft payloads, communications antennas, radar reflectors, and solar concentrators. Such deployable trusses could also be useful in terrestrial applications such as the rapid establishment of structures in military and emergency service situations, in particular with regard to the deployment of enclosures for habitat or storage. To minimize the time required to deploy such an enclosure, a single arch-shaped truss is preferable to multiple straight trusses arranged vertically and horizontally. To further minimize the time required to deploy such an enclosure, a synchronous deployment with a single degree of freedom is also preferable. One method of synchronizing deployment of a truss is the use of a series of gears; this makes the deployment sequence predictable and testable, allows the truss to have a minimal stowage volume, and the deployed structure exhibits the excellent stiffness-to-mass and strength-to-mass ratios characteristic of a truss. A concept for using gears with varying ratios to deploy a truss into a curved shape has been developed and appears to be compatible with both space technology applications as well as potential use in terrestrial applications such as enclosure deployment. As is the case with other deployable trusses, this truss is formed using rigid elements (e.g., composite tubes) along the edges, one set of diagonal elements composed of either cables or folding/hinged rigid members, and the other set of diagonal elements formed by a continuous cable that is tightened by a motor or hand crank in order to deploy the truss. Gears of varying ratios are used to constrain the deployment to a single degree of freedom, making the deployment synchronous, predictable, and repeatable. The relative sizes of the gears and the relative dimensions of the diagonal elements determine the deployed geometry (e

  12. An Efficient Algorithm for Stiffness Identification of Truss Structures Through Distributed Local Computation

    NASA Astrophysics Data System (ADS)

    Zhang, G.; Burgueño, R.; Elvin, N. G.

    2010-02-01

    This paper presents an efficient stiffness identification technique for truss structures based on distributed local computation. Sensor nodes on each element are assumed to collect strain data and communicate only with sensors on neighboring elements. This can significantly reduce the energy demand for data transmission and the complexity of transmission protocols, thus enabling a simplified wireless implementation. Element stiffness parameters are identified by simple low order matrix inversion at a local level, which reduces the computational energy, allows for distributed computation and makes parallel data processing possible. The proposed method also permits addressing the problem of missing data or faulty sensors. Numerical examples, with and without missing data, are presented and the element stiffness parameters are accurately identified. The computation efficiency of the proposed method is n2 times higher than previously proposed global damage identification methods.

  13. Adaptive Space Structures

    NASA Technical Reports Server (NTRS)

    Wada, B.

    1993-01-01

    The term adaptive structures refers to a structural control approach in which sensors, actuators, electronics, materials, structures, structural concepts, and system-performance-validation strategies are integrated to achieve specific objectives.

  14. Zenith 1 truss transfer ceremony

    NASA Technical Reports Server (NTRS)

    2000-01-01

    The Zenith-1 (Z-1) Truss, the cornerstone truss of the Space Station, is shown on the floor of the Space Station Processing Facility. The Z-1 Truss was officially turned over to NASA from The Boeing Co. on July 31. It is scheduled to fly in Space Shuttle Discovery's payload pay on STS-92 targeted for launch Oct. 5, 2000. The Z-1 is considered a cornerstone truss because it carries critical components of the Station's attitude, communications, thermal and power control systems as well as four control moment gyros, high and low gain antenna systems, and two plasma contactor units used to disperse electrical charge build- ups. The Z-1 truss and a Pressurized Mating Adapter (PMA-3), also flying to the Station on the same mission, will be the first major U.S. elements flown to the ISS aboard the Shuttle since the launch of the Unity element in December 1998.

  15. Selection of active member locations in adaptive structures

    NASA Technical Reports Server (NTRS)

    Chen, G.-S.; Bruno, R.; Salama, M.

    1989-01-01

    The effective use of multiple passive and active members in adaptive structures necessitates that these members be optimally distributed throughout the structure. In truss structures, the problem falls into the class of combinatorial optimization for which the solution becomes exceedingly intractable as the problem size increases. This is overcome by using the simulated annealing algorithm to obtain near optimal locations for passive and/or active members. The maximization of the rate of energy dissipation over a finite time period as the measure of optimality is adopted. The selection of optimal locations for both passive and active members is consistently treated through the use of the energy dissipation rate criterion within the simulated annealing algorithm. Numerical examples are used to illustrate the effectiveness of the methodology for large truss structures.

  16. Joint U.S./Japan Conference on Adaptive Structures, 1st, Maui, HI, Nov. 13-15, 1990, Proceedings

    NASA Technical Reports Server (NTRS)

    Wada, Ben K. (Editor); Fanson, James L. (Editor); Miura, Koryo (Editor)

    1991-01-01

    The present volume of adaptive structures discusses the development of control laws for an orbiting tethered antenna/reflector system test scale model, the sizing of active piezoelectric struts for vibration suppression on a space-based interferometer, the control design of a space station mobile transporter with multiple constraints, and optimum configuration control of an intelligent truss structure. Attention is given to the formulation of full state feedback for infinite order structural systems, robustness issues in the design of smart structures, passive piezoelectric vibration damping, shape control experiments with a functional model for large optical reflectors, and a mathematical basis for the design optimization of adaptive trusses in precision control. Topics addressed include approaches to the optimal adaptive geometries of intelligent truss structures, the design of an automated manufacturing system for tubular smart structures, the Sandia structural control experiments, and the zero-gravity dynamics of space structures in parabolic aircraft flight.

  17. Wedge Joints for Trusses

    NASA Technical Reports Server (NTRS)

    Wood, Kenneth E.

    1987-01-01

    Structure assembled rapidly with simple hand tools. Proposed locking wedge joints enable rapid assembly of lightweight beams, towers, scaffolds, and other truss-type structures. Lightweight structure assembled from tubular struts joined at nodes by wedge pins fitting into mating slots. Joint assembled rapidly by seating wedge pin in V-shaped slots and deforming end of strut until primary pawl engages it.

  18. Optimal design at inner core of the shaped pyramidal truss structure

    SciTech Connect

    Lee, Sung-Uk; Yang, Dong-Yol

    2013-12-16

    Sandwich material is a type of composite material with lightweight, high strength, good dynamic properties and high bending stiffness-to-weight ratio. This can be found well such structures in the nature (for example, internal structure of bones, plants, etc.). New trend which prefers eco-friendly products and energy efficiency is emerging in industries recently. Demand for materials with high strength and light weight is also increasing. In line with these trends, researches about manufacturing methods of sandwich material have been actively conducted. In this study, a sandwich structure named as “Shaped Pyramidal Truss Structure” is proposed to improve mechanical strength and to apply a manufacturing process suitable for massive production. The new sandwich structure was designed to enhance compressive strength by changing the cross-sectional shape at the central portion of the core. As the next step, optimization of the shape was required. Optimization technique used here was the SZGA(Successive Zooming Genetic Algorithm), which is one of GA(Genetic Algorithm) methods gradually reducing the area of design variable. The objective function was defined as moment of inertia of the cross-sectional shape of the strut. The control points of cubic Bezier curve, which was assumed to be the shape of the cross section, were used as design variables. By using FEM simulation, it was found that the structure exhibited superior mechanical properties compared to the simple design of the prior art.

  19. Joint Japan/U.S. Conference on Adaptive Structures, 2nd, Nagoya, Japan, Nov. 12-14, 1991, Collection of Papers

    NASA Technical Reports Server (NTRS)

    Matsuzaki, Yuji (Editor); Wada, Ben K. (Editor)

    1992-01-01

    The present conference discusses the development status of adaptive structures in Europe and in Japan, the 'Cosmo-Lab' structures/robotics cooperation concept, active-adhesion concepts for in-orbit structural assembly, adaptively controlled truss structures, object-oriented modeling in structural analysis, the control effectiveness and energy efficiency of an active mass damper, a space truss with experimental tendon control, and piezoelectric actuator-based space trusses. Also discussed is the control of resonant frequencies in adaptive structures through prestressing, active control of vortex-excited vibrations of flexible cylindrical structures, shape adjustment of a flexible space antenna reflector, the SDIO Adaptive Structures Program, optimal trajectories of iterative manipulation for space robots, a docking device as an adaptive structure, shape-memory polymers and their hybrid composites, and fuzzy control methods for structural dynamics.

  20. Joint Japan/U. S. Conference on Adaptive Structures, 2nd, Nagoya, Japan, Nov. 12-14, 1991, Collection of Papers

    SciTech Connect

    Matsuzaki, Y.; Wada, B.K.

    1992-01-01

    The present conference discusses the development status of adaptive structures in Europe and in Japan, the 'Cosmo-Lab' structures/robotics cooperation concept, active-adhesion concepts for in-orbit structural assembly, adaptively controlled truss structures, object-oriented modeling in structural analysis, the control effectiveness and energy efficiency of an active mass damper, a space truss with experimental tendon control, and piezoelectric actuator-based space trusses. Also discussed is the control of resonant frequencies in adaptive structures through prestressing, active control of vortex-excited vibrations of flexible cylindrical structures, shape adjustment of a flexible space antenna reflector, the SDIO Adaptive Structures Program, optimal trajectories of iterative manipulation for space robots, a docking device as an adaptive structure, shape-memory polymers and their hybrid composites, and fuzzy control methods for structural dynamics.

  1. Joint nonlinearity effects in the design of a flexible truss structure control system

    NASA Technical Reports Server (NTRS)

    Mercadal, Mathieu

    1986-01-01

    Nonlinear effects are introduced in the dynamics of large space truss structures by the connecting joints which are designed with rather important tolerances to facilitate the assembly of the structures in space. The purpose was to develop means to investigate the nonlinear dynamics of the structures, particularly the limit cycles that might occur when active control is applied to the structures. An analytical method was sought and derived to predict the occurrence of limit cycles and to determine their stability. This method is mainly based on the quasi-linearization of every joint using describing functions. This approach was proven successful when simple dynamical systems were tested. Its applicability to larger systems depends on the amount of computations it requires, and estimates of the computational task tend to indicate that the number of individual sources of nonlinearity should be limited. Alternate analytical approaches, which do not account for every single nonlinearity, or the simulation of a simplified model of the dynamical system should, therefore, be investigated to determine a more effective way to predict limit cycles in large dynamical systems with an important number of distributed nonlinearities.

  2. The Z1 truss begins its ride up the RSS on Launch Pad 39A

    NASA Technical Reports Server (NTRS)

    2000-01-01

    With the onset of dawn, the payload canister (left) with the Integrated Truss Structure Z1 inside begins its journey up the side of the Rotating Service Structure to the Payload Changeout Room. There the Z1 truss will be removed and later transferred to Space Shuttle Discovery's payload bay. The Z1 truss is the first of 10 that will become the backbone of the International Space Station, eventually stretching the length of a football field. Along with its companion payload, the third Pressurized Mating Adapter, the Z1 is scheduled to be launched aboard Discovery Oct. 5 at 9:38 p.m. EDT.

  3. The Z1 truss begins its ride up the RSS on Launch Pad 39A

    NASA Technical Reports Server (NTRS)

    2000-01-01

    As the sky grows lighter, , the payload canister (left) with the Integrated Truss Structure Z1 inside is slowly lifted up the side of the Rotating Service Structure to the Payload Changeout Room. There the Z1 truss will be removed and later transferred to Space Shuttle Discovery's payload bay. The Z1 truss is the first of 10 that will become the backbone of the International Space Station, eventually stretching the length of a football field. Along with its companion payload, the third Pressurized Mating Adapter, the Z1 is scheduled to be launched aboard Discovery Oct. 5 at 9:38 p.m. EDT.

  4. Evaluation of boron-epoxy-reinforced titanium tubular truss for application to a space shuttle booster thrust structure

    NASA Technical Reports Server (NTRS)

    Corvelli, N.; Carri, R.

    1972-01-01

    Results of a study to demonstrate the applicability of boron-epoxy-composite-reinforced titanium tubular members to a space shuttle booster thrust structure are presented and discussed. The experimental results include local buckling of all-composite and composite-reinforced-metal cylinders with low values of diameter-thickness ratio, static tests on composite-to-metal bonded step joints, and a test to failure of a boron-epoxy-reinforced titanium demonstration truss. The demonstration truss failed at 118 percent of design ultimate load. Test results and analysis for all specimens and the truss are compared. Comparing an all-titanium design and a boron-epoxy-reinforced-titanium (75 percent B-E and 25 percent Ti) design for application to the space shuttle booster thrust structure indicates that the latter would weigh approximately 24 percent less. Experimental data on the local buckling strength of cylinders with a diameter-thickness ratio of approximately 50 are needed to insure that undue conservatism is not used in future designs.

  5. The Z1 truss is lifted up the RSS on Launch Pad 39A

    NASA Technical Reports Server (NTRS)

    2000-01-01

    With its umbilical hoses stretched out, the payload canister (left) with the Integrated Truss Structure Z1 inside nears the top of the passage to the Payload Changeout Room. There the Z1 truss will be removed and later transferred to Space Shuttle Discovery's payload bay. The Z1 truss is the first of 10 that will become the backbone of the International Space Station, eventually stretching the length of a football field. Along with its companion payload, the third Pressurized Mating Adapter, the Z1 is scheduled to be launched aboard Discovery Oct. 5 at 9:38 p.m. EDT.

  6. Intelligent adaptive structures

    NASA Technical Reports Server (NTRS)

    Wada, Ben K.

    1990-01-01

    'Intelligent Adaptive Structures' (IAS) refers to structural systems whose geometric and intrinsic structural characteristics can be automatically changed to meet mission requirements with changing operational scenarios. An IAS is composed of actuators, sensors, and a control logic; these are integrated in a distributed fashion within the elements of the structure. The IAS concepts thus far developed for space antennas and other precision structures should be applicable to civil, marine, automotive, and aeronautical structural systems.

  7. Graphite composite truss welding and cap section forming subsystems. Volume 1: Executive summary. [large space structures

    NASA Technical Reports Server (NTRS)

    1980-01-01

    A rolltrusion process was developed for forming of a hybrid, single-ply woven graphite and glass fiber cloth, impregnated with a polysulfone resin and coated with TI02 pigmented P-1700 resin into strips for the on-orbit fabrication of triangular truss segments. Ultrasonic welding in vacuum showed no identifiable effects on weld strength or resin flow characteristics. An existing bench model cap roll forming machine was modified and used to roll form caps for the prototype test truss and for column test specimens in order to test local buckling and torsional instability characteristics.

  8. End-effector for robotic assembly of welded truss structures in space

    NASA Technical Reports Server (NTRS)

    Brewer, William V.

    1991-01-01

    In June 1987, work was initiated at LaRC on end-effectors and preloaded joints for robotic truss assembly. This is part of an on-going research effort centered on a test facility that assembles 1 inch x 2 m identical struts into an 8 m diameter x 1.5 m deep platform truss. A detailed description of the test facility was published. The end-effector being used for the LaRC assembly demonstration is quite suitable for the Precision Segmented Reflector or other precision applications. These require high stiffness provided by mechanical joint preloads. Stiffness obtained in this manner is only required and provided over a load range far less than the ultimate strength of the strut tubes. Beyond this useful range, truss behavior is somewhat unpredictable. Mechanically preloaded joints of this type are less suitable for applications such as the Aero Brake where predictable strength and stiffness are required over a greater fraction of the load bearing capacity of component parts. Preliminary studies of the Aerobrake support truss indicate that struts of at least 3 different diameters and various lengths would improve performance. The double-ended end-effector currently in service is designed for only one diameter and length. Anticipated single-ended versions can accommodate varying lengths but not multiple diameters. Tradeoff considerations for welded joints relative to their mechanically preloaded counterparts are presented. Conclusions from this research are as follows: (1) repair by cut and re-weld on the original weld site should be research; (2) welded joints, though repairable, should not be used where high repair frequencies are anticipated; and (3) welded joints should be considered for an Aero Brake truss.

  9. Adaptive structures; Proceedings of the ASME Winter Annual Meeting, San Francisco, CA, Dec. 10-15, 1989

    NASA Technical Reports Server (NTRS)

    Wada, Ben K. (Editor)

    1989-01-01

    The present conference on adaptive structures discusses piezoelectric and electrostrictive sensors and actuators for adaptive structures and smart materials, real-time control for composite structures with embedded actuators and sensors, a laminated-shell theory incorporating embedded distributed actuators, traveling-wave power flow techniques, uncertainty modeling for the control of an active structure, and active vibration isolation in the presence of unmodeled structural dynamic response. Also discussed are the control of flexible beams via free-free active truss, truss structure control using member actuators with latch mechanism, neural processors for smart-structure control, the effect of imperfections on the static control of adaptive structures, adaptive structures for segmented optical systems, and the shape-control of flexible structures.

  10. Zenith 1 truss transfer ceremony

    NASA Technical Reports Server (NTRS)

    2000-01-01

    The Zenith-1 (Z-1) Truss is officially presented to NASA by The Boeing Co. on the Space Station Processing Facility floor on July 31. STS-92 Commander Col. Brian Duffy discusses the significance of the Z-1 Truss during a press conference after the presentation. The Z-1 Truss is the cornerstone truss of the International Space Station and is scheduled to fly in Space Shuttle Discovery's payload pay on STS-92 targeted for launch Oct. 5, 2000. The Z-1 is considered a cornerstone truss because it carries critical components of the Station's attitude, communications, thermal and power control systems as well as four control moment gyros, high and low gain antenna systems, and two plasma contactor units used to disperse electrical charge build- ups. The Z-1 truss and a Pressurized Mating Adapter (PMA-3), also flying to the Station on the same mission, will be the first major U.S. elements flown to the ISS aboard the Shuttle since the launch of the Unity element in December 1998.

  11. Zenith 1 truss transfer ceremony

    NASA Technical Reports Server (NTRS)

    2000-01-01

    The STS-92 astronaut team study the the Zenith-1 (Z-1) Truss during the Crew Equipment Interface Test. The Z-1 Truss was officially presented to NASA by The Boeing Co. on the Space Station Processing Facility floor on July 31. The truss is the cornerstone truss of the International Space Station and is scheduled to fly in Space Shuttle Discovery's payload pay on STS- 92 targeted for launch Oct. 5, 2000. The Z-1 is considered a cornerstone truss because it carries critical components of the Station's attitude, communications, thermal and power control systems as well as four control moment gyros, high and low gain antenna systems, and two plasma contactor units used to disperse electrical charge build-ups. The Z-1 truss and a Pressurized Mating Adapter (PMA-3), also flying to the Station on the same mission, will be the first major U.S. elements flown to the ISS aboard the Shuttle since the launch of the Unity element in December 1998.

  12. Zenith 1 truss transfer ceremony

    NASA Technical Reports Server (NTRS)

    2000-01-01

    The Zenith-1 (Z-1) Truss is officially presented to NASA by The Boeing Co. on the Space Station Processing Facility floor on July 31. STS-92 Commander Col. Brian Duffy, comments on the presentation. At his side is Tip Talone, NASA director of International Space Station and Payload Processing at KSC. Talone and Col. Duffy received a symbolic key for the truss from John Elbon, Boeing director of ISS ground operations. The Z-1 Truss is the cornerstone truss of the International Space Station and is scheduled to fly in Space Shuttle Discovery's payload pay on STS- 92 targeted for launch Oct. 5, 2000. The Z-1 is considered a cornerstone truss because it carries critical components of the Station's attitude, communications, thermal and power control systems as well as four control moment gyros, high and low gain antenna systems, and two plasma contactor units used to disperse electrical charge build-ups. The Z-1 truss and a Pressurized Mating Adapter (PMA-3), also flying to the Station on the same mission, will be the first major U.S. elements flown to the ISS aboard the Shuttle since the launch of the Unity element in December 1998.

  13. Zenith 1 truss transfer ceremony

    NASA Technical Reports Server (NTRS)

    2000-01-01

    A wide-angle view of the floor of the Space Station Processing Facility. The floor is filled with racks and hardware for processing and testing the various components of the International Space Station (ISS). At the bottom left is the Zenith-1 (Z-1) Truss, the cornerstone truss of the Space Station. The Z-1 Truss was officially turned over to NASA from The Boeing Co. on July 31. The truss is scheduled to fly in Space Shuttle Discovery's payload pay on STS-92 targeted for launch Oct. 5, 2000. The Z-1 is considered a cornerstone truss because it carries critical components of the Station's attitude, communications, thermal and power control systems as well as four control moment gyros, high and low gain antenna systems, and two plasma contactor units used to disperse electrical charge build- ups. The Z-1 truss and a Pressurized Mating Adapter (PMA-3), also flying to the Station on the same mission, will be the first major U.S. elements flown to the ISS aboard the Shuttle since the launch of the Unity element in December 1998. The large module in the center of the floor is the U.S. Lab, Destiny. Expected to be a major feature in future research, Destiny will provide facilities for biotechnology, fluid physics, combustion, and life sciences research. It is scheduled to be launched on mission STS- 98 (no date determined yet for launch).

  14. Two Concepts for Deployable Trusses

    NASA Technical Reports Server (NTRS)

    Renfro, John W.

    2010-01-01

    Two concepts that could be applied separately or together have been suggested to enhance the utility of deployable truss structures. The concepts were intended originally for application to a truss structure to be folded for compact stowage during transport and subsequently deployed in outer space. The concepts may also be applicable, with some limitations, to deployable truss structures designed to be used on Earth. The first concept involves a combination of features that would help to maximize reliability of a structure while minimizing its overall mass, the complexity of its deployment system, and the expenditure of energy for deployment. The deployment system would be integrated into the truss: some of the truss members would contain folding/unfolding-detent mechanisms similar to those in umbrellas; other truss members would contain shape-memory-alloy (SMA) coil actuators (see Figure 1). Upon exposure to sunlight, the SMA actuators would be heated above their transition temperature, causing them to extend to their deployment lengths. The extension of the actuators would cause the structure to unfold and, upon completion of unfolding, the umbrellalike mechanisms would lock the unfolded truss in the fully deployed configuration. The use of solar heating to drive deployment would eliminate the need to carry a deployment power source. The actuation scheme would offer high reliability in that the truss geometry would be such that deployment could be completed even if all actuators were not functioning. Of course, in designing for operation in normal Earth gravitation, it would be necessary to ensure that the SMA actuators could apply forces large enough to overcome the deploymentresisting forces attributable to the weights of the members. The second concept is that of an improved design for the joints in folding members. Before describing this design,

  15. Newly Installed S-1 Truss

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Launched October 7, 2002 aboard the Space Shuttle Orbiter Atlantis, the STS-112 mission lasted 11 days and performed three sessions of Extra Vehicular Activity (EVA). Its primary mission was to install the Starboard (S1) Integrated Truss Structure and Equipment Translation Aid (CETA) Cart to the International Space Station (ISS). The S1 truss provides structural support for the orbiting research facility's radiator panels, which use ammonia to cool the Station's complex power system. The S1 truss, attached to the S0 (S Zero) truss installed by the previous STS-110 mission, flows 637 pounds of anhydrous ammonia through three heat rejection radiators. The truss is 45-feet long, 15-feet wide, 10-feet tall, and weighs approximately 32,000 pounds. The CETA is the first of two human-powered carts that will ride along the International Space Station's railway providing a mobile work platform for future extravehicular activities by astronauts. This is a view of the newly installed S1 Truss as photographed during the mission's first scheduled EVA. The Station's Canadarm2 is in the foreground. Visible are astronauts Piers J. Sellers (lower left) and David A. Wolf (upper right), both STS-112 mission specialists.

  16. Adaptive Structures Flight Experiments

    NASA Technical Reports Server (NTRS)

    Martin, Maurice

    1992-01-01

    The topics are presented in viewgraph form and include the following: adaptive structures flight experiments; enhanced resolution using active vibration suppression; Advanced Controls Technology Experiment (ACTEX); ACTEX program status; ACTEX-2; ACTEX-2 program status; modular control patch; STRV-1b Cryocooler Vibration Suppression Experiment; STRV-1b program status; Precision Optical Bench Experiment (PROBE); Clementine Spacecraft Configuration; TECHSAT all-composite spacecraft; Inexpensive Structures and Materials Flight Experiment (INFLEX); and INFLEX program status.

  17. Adaptive structures flight experiments

    NASA Astrophysics Data System (ADS)

    Martin, Maurice

    The topics are presented in viewgraph form and include the following: adaptive structures flight experiments; enhanced resolution using active vibration suppression; Advanced Controls Technology Experiment (ACTEX); ACTEX program status; ACTEX-2; ACTEX-2 program status; modular control patch; STRV-1b Cryocooler Vibration Suppression Experiment; STRV-1b program status; Precision Optical Bench Experiment (PROBE); Clementine Spacecraft Configuration; TECHSAT all-composite spacecraft; Inexpensive Structures and Materials Flight Experiment (INFLEX); and INFLEX program status.

  18. 24. Moody Bridge truss repair plans showing existing area of ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    24. Moody Bridge truss repair plans showing existing area of damage along with repair procedures for correcting damage and returning truss to structural integrity. - Moody Bridge, Spanning South Fork Eel River, Garberville, Humboldt County, CA

  19. Adaptive building skin structures

    NASA Astrophysics Data System (ADS)

    Del Grosso, A. E.; Basso, P.

    2010-12-01

    The concept of adaptive and morphing structures has gained considerable attention in the recent years in many fields of engineering. In civil engineering very few practical applications are reported to date however. Non-conventional structural concepts like deployable, inflatable and morphing structures may indeed provide innovative solutions to some of the problems that the construction industry is being called to face. To give some examples, searches for low-energy consumption or even energy-harvesting green buildings are amongst such problems. This paper first presents a review of the above problems and technologies, which shows how the solution to these problems requires a multidisciplinary approach, involving the integration of architectural and engineering disciplines. The discussion continues with the presentation of a possible application of two adaptive and dynamically morphing structures which are proposed for the realization of an acoustic envelope. The core of the two applications is the use of a novel optimization process which leads the search for optimal solutions by means of an evolutionary technique while the compatibility of the resulting configurations of the adaptive envelope is ensured by the virtual force density method.

  20. Box truss development and its application

    NASA Technical Reports Server (NTRS)

    Coyner, J. V.

    1985-01-01

    Since 1977, Martin Marietta Denver Aerospace has aggressively pursued development of deployable structural systems applicable to a wide variety of Shuttle-transportable large space system requirements. This effort has focused on the deployable box truss, mechanisms and materials development, mesh reflector design and fabrication, gate frame truss design and fabrication, and offset-fed antenna design and analysis. The activities discussed are: box truss design; metal matrix composites; precision joints; enhanced passive damping design; mesh reflector development; gate frame truss for solar arrays; 15-meter spinning radio meter; and 60 x 120 meter push broom antenna.

  1. System Identification of Damped Truss-Like Space Structures. Ph.D. Thesis - Cleveland State Univ., Mar. 1994

    NASA Technical Reports Server (NTRS)

    Armand, Sasan

    1995-01-01

    A spacecraft payload flown on a launch vehicle experiences dynamic loads. The dynamic loads are caused by various phenomena ranging from the start-up of the launch vehicle engine to wind gusts. A spacecraft payload should be designed to meet launch vehicle dynamic loads. One of the major steps taken towards determining the dynamic loads is to correlate the finite element model of the spacecraft with the test results of a modal survey test. A test-verified finite element model of the spacecraft should possess the same spatial properties (stiffness, mass, and damping) and modal properties (frequencies and mode shapes) as the test hardware representing the spacecraft. The test-verified and correlated finite element model of the spacecraft is then coupled with the finite element model of the launch vehicle for analysis of loads and stress. Modal survey testing, verification of a finite element model, and modification of the finite element model to match the modal survey test results can easily be accomplished if the spacecraft structure is simple. However, this is rarely the case. A simple structure here is defined as a structure where the influence of nonlinearity between force and displacement (uncertainty in a test, for example, with errors in input and output), and the influence of damping (structural, coulomb, and viscous) are not pronounced. The objective of this study is to develop system identification and correlation methods with the focus on the structural systems that possess nonproportional damping. Two approaches to correct the nonproportional damping matrix of a truss structure were studied, and have been implemented on truss-like structures such as the National Aeronautics and Space Administration's space station truss. The results of this study showed nearly 100 percent improvement of the correlated eigensystem over the analytical eigensystem. The first method showed excellent results with up to three modes used in the system identification process. The

  2. Strut-node joint conjugates for the assembly of semi-permanent or reusable truss structures

    NASA Technical Reports Server (NTRS)

    Brewer, W. V.

    1989-01-01

    When strut and node components are used for truss construction an assembly problem occurs if a strut must be fitted between nodes whose separation distance is either closer or farther than the design intended. This condition is the result of normal dimensional variations that occur in any manufacturing process. In such circumstances two actions would permit continued assembly: change the effective strut length, and move the nodes. Assuming continued assembly is the most attractive alternative, attention is focused on accomplishing these actions as part of the assembly process.

  3. Zenith 1 truss transfer ceremony

    NASA Technical Reports Server (NTRS)

    2000-01-01

    A wide-angle view of the floor of the Space Station Processing Facility. The floor is filled with racks and hardware for processing and testing the various components of the International Space Station (ISS). At center left is the Zenith-1 (Z-1) Truss, the cornerstone truss of the Space Station. The Z-1 Truss was officially turned over to NASA from The Boeing Co. on July 31. It is scheduled to fly in Space Shuttle Discovery's payload pay on STS-92 targeted for launch Oct. 5, 2000. The Z-1 is considered a cornerstone truss because it carries critical components of the Station's attitude, communications, thermal and power control systems as well as four control moment gyros, high and low gain antenna systems, and two plasma contactor units used to disperse electrical charge build-ups. The Z-1 truss and a Pressurized Mating Adapter (PMA-3), also flying to the Station on the same mission, will be the first major U.S. elements flown to the ISS aboard the Shuttle since the launch of the Unity element in December 1998. The large module in the upper right hand corner of the floor is the U.S. Lab, Destiny. Expected to be a major feature in future research, Destiny will provide facilities for biotechnology, fluid physics, combustion, and life sciences research. It is scheduled to be launched on mission STS-98 (no date determined yet for launch).

  4. Zenith 1 truss transfer ceremony

    NASA Technical Reports Server (NTRS)

    2000-01-01

    The Zenith-1 (Z-1) Truss is officially presented to NASA by The Boeing Co. on the Space Station Processing Facility floor on July 31. Astronauts from the STS-92 crew look on while their commander, Col. Brian Duffy, and Tip Talone, NASA director of International Space Station and Payload Processing at KSC, receive a symbolic key from John Elbon, Boeing director of ISS ground operations. The Z-1 Truss is the cornerstone truss of the International Space Station and is scheduled to fly in Space Shuttle Discovery's payload pay on STS-92 targeted for launch Oct. 5, 2000. The Z-1 is considered a cornerstone truss because it carries critical components of the Station's attitude, communications, thermal and power control systems as well as four control moment gyros, high and low gain antenna systems, and two plasma contactor units used to disperse electrical charge build- ups. The Z-1 truss and a Pressurized Mating Adapter (PMA-3), also flying to the Station on the same mission, will be the first major U.S. elements flown to the ISS aboard the Shuttle since the launch of the Unity element in December 1998.

  5. Implementation of a modal filter on a five meter truss structure

    NASA Technical Reports Server (NTRS)

    Shelly, S.; Allemang, R. J.; Freudinger, L.; Zhang, Q.

    1991-01-01

    Modal filtering is a spatial filtering technique which uses a weighted sum of a number of response measurements to extract the modal coordinates of the system from the physical response coordinates. No moving average or autoregressive calculations are required to implement the modal filter thus the modal coordinates may be calculated in real time. For practical implementation of the modal filter, the number and location of response locations must be chosen carefully. A modal filter is implemented on a five meter model space truss as a case study. The modal coordinates are extracted in real time using Hewlett Packard 3565 data acquisition and processig hardware. The effect of the number and location of response measurements on the performance of the modal filter is investigated. Applications of the modal filter to modal control and fast parameter identification are also discussed.

  6. The adaptable lyonsite structure.

    PubMed

    Smit, Jared P; Stair, Peter C; Poeppelmeier, Kenneth R

    2006-08-01

    Crystal frameworks that can accommodate a wide range of elements, oxidation states, and stoichiometries are an important component of solid-state chemistry. These frameworks allow for unique comparisons of different metal-cation compositions with identical atomic arrangements. The mineral Lyonsite, alpha-Cu(3)Fe(4)(VO(4))(6), is emerging as the archetypal framework structure for a large class of materials, similar to known frameworks such as perovskite, garnet, apatite, and spinel. The new lyonsite-type oxides Li(2.82)Hf(0.795)Mo(3)O(12) and Li(3.35)Ta(0.53)Mo(3)O(12), in which hafnium and tantalum retain their highest oxidation states, are presented to advance the concept of the lyonsite structure as an adaptable framework. PMID:16755622

  7. P-1 truss arrival at KSC

    NASA Technical Reports Server (NTRS)

    2000-01-01

    The P-1 truss, a component of the International Space Station, is moved from the Shuttle Landing Facility toward the newly constructed RLV hangar (viewed here from inside the hangar) as precaution against bad weather approaching the Center (background). The truss will eventually be transferred to the Operations and Checkout Building for processing. In the background is the Super Guppy transport that brought it to KSC. The P-1 truss, scheduled to fly in spring of 2002, is part of a total 10-truss, girder-like structure on the Station that will ultimately extend the length of a football field. Astronauts will attach the 14-by-15 foot structure to the port side of the center truss, S0, during the spring assembly flight. The 33,000-pound P- 1 will house the thermal radiator rotating joint (TRRJ) that will rotate the Station's radiators away from the sun to increase their maximum cooling efficiency.

  8. P-1 truss arrival at KSC

    NASA Technical Reports Server (NTRS)

    2000-01-01

    The P-1 truss, a component of the International Space Station, arrives inside the RLV hangar, located near the Shuttle Landing Facility at KSC. Approaching bad weather caused the detour as a precaution. The truss will eventually be transferred to the Operations and Checkout Building for processing. The P-1 truss, scheduled to fly in spring of 2002, is part of a total 10-truss, girder-like structure on the Station that will ultimately extend the length of a football field. Astronauts will attach the 14-by- 15 foot structure to the port side of the center truss, S0, during the spring assembly flight. The 33,000-pound P-1 will house the thermal radiator rotating joint (TRRJ) that will rotate the Station's radiators away from the sun to increase their maximum cooling efficiency.

  9. Space truss zero gravity dynamics

    NASA Technical Reports Server (NTRS)

    Swanson, Andy

    1989-01-01

    The Structural Dynamics Branch of the Air Force Flight Dynamics Laboratory in cooperation with the Reduced Gravity Office of the NASA Lyndon B. Johnson Space Center (JSC) plans to perform zero-gravity dynamic tests of a 12-meter truss structure. This presentation describes the program and presents all results obtained to date.

  10. STS-112 S1 Truss is transported to the payload canister

    NASA Technical Reports Server (NTRS)

    2002-01-01

    KENNEDY SPACE CENTER, FLA. -- An overhead crane moves the S1 Integrated Truss Structure toward the payload canister, which will transport it to Atlantis. The first starboard truss segment, the S1 will be attached to the Central truss segment, the S0 Truss, on the International Space Station during mission STS-112. Atlantis is scheduled to launch no earlier than Oct. 2.

  11. STS-112 S1 Truss is transported to the payload canister

    NASA Technical Reports Server (NTRS)

    2002-01-01

    KENNEDY SPACE CENTER, FLA. -- The S1 Integrated Truss Structure is lowered into the payload canister for transport to Atlantis. The first starboard truss segment, the S1 will be attached to the Central truss segment, the S0 Truss, on the International Space Station during mission STS-112. Atlantis is scheduled to launch no earlier than Oct. 2.

  12. STS-112 S1 Truss is transported to the payload canister

    NASA Technical Reports Server (NTRS)

    2002-01-01

    KENNEDY SPACE CENTER, FLA. -- An overhead crane moves the S1 Integrated Truss Structure toward the payload canister below, which will transport it to Atlantis. The first starboard truss segment, the S1 will be attached to the Central truss segment, the S0 Truss, on the International Space Station during mission STS-112. Atlantis is scheduled to launch no earlier than Oct. 2.

  13. Self-Deploying Trusses Containing Shape-Memory Polymers

    NASA Technical Reports Server (NTRS)

    Schueler, Robert M.

    2008-01-01

    Composite truss structures are being developed that can be compacted for stowage and later deploy themselves to full size and shape. In the target applications, these smart structures will precisely self-deploy and support a large, lightweight space-based antenna. Self-deploying trusses offer a simple, light, and affordable alternative to articulated mechanisms or inflatable structures. The trusses may also be useful in such terrestrial applications as variable-geometry aircraft components or shelters that can be compacted, transported, and deployed quickly in hostile environments. The truss technology uses high-performance shape-memory-polymer (SMP) thermoset resin reinforced with fibers to form a helical composite structure. At normal operating temperatures, the truss material has the structural properties of a conventional composite. This enables truss designs with required torsion, bending, and compression stiffness. However, when heated to its designed glass transition temperature (Tg), the SMP matrix acquires the flexibility of an elastomer. In this state, the truss can be compressed telescopically to a configuration encompassing a fraction of its original volume. When cooled below Tg, the SMP reverts to a rigid state and holds the truss in the stowed configuration without external constraint. Heating the materials above Tg activates truss deployment as the composite material releases strain energy, driving the truss to its original memorized configuration without the need for further actuation. Laboratory prototype trusses have demonstrated repeatable self-deployment cycles following linear compaction exceeding an 11:1 ratio (see figure).

  14. Design, development and fabrication of a deployable/retractable truss beam model for large space structures application

    NASA Technical Reports Server (NTRS)

    Adams, Louis R.

    1987-01-01

    The design requirements for a truss beam model are reviewed. The concept behind the beam is described. Pertinent analysis and studies concerning beam definition, deployment loading, joint compliance, etc. are given. Design, fabrication and assembly procedures are discussed.

  15. The P4 truss is moved to a workstand in the SSPF

    NASA Technical Reports Server (NTRS)

    2000-01-01

    In the Space Station Processing Facility, workers get ready to lower the International Space Station's P4 truss onto a workstand. Part of the 10-truss, girder-like structure that will ultimately extend the length of a football field, the P4 is the second port truss segment that will attach to the first port truss segment (P1 truss). The P4 is scheduled for mission 12A in September 2002.

  16. The P4 truss is moved to a workstand in the SSPF

    NASA Technical Reports Server (NTRS)

    2000-01-01

    In the Space Station Processing Facility, workers oversee the removal of the P4 truss from the truck that transported it from Tulsa, Okla. Part of the 10-truss, girder-like structure that will ultimately extend the length of a football field on the International Space Station, the P4 is the second port truss segment that will attach to the first port truss segment (P1 truss). The P4 is scheduled for mission 12A in September 2002.

  17. The P4 truss is moved to a workstand in the SSPF

    NASA Technical Reports Server (NTRS)

    2000-01-01

    In the Space Station Processing Facility, an overhead crane moves the P4 truss to a workstand. Part of the 10-truss, girder-like structure that will ultimately extend the length of a football field on the International Space Station, the P4 is the second port truss segment that will attach to the first port truss segment (P1 truss). The P4 is scheduled for mission 12A in September 2002.

  18. STS-113 Mission Specialists review data on the P1 Truss

    NASA Technical Reports Server (NTRS)

    2002-01-01

    KENNEDY SPACE CENTER, FLA. -- STS-113 Mission Specialists John Herrington (left) and Michael Lopez-Alegria (right) look over the P1 Integrated Truss Structure, the primary payload for the mission. The P1 truss will be attached to the central truss segment, S0 Truss, during spacewalks. The payload also includes the Crew and Equipment Translation Aid (CETA) Cart B that can be used by spacewalkers to move along the truss with equipment. STS-113 is scheduled to launch Oct. 6, 2002

  19. STS-113 Mission Specialists review data on the P1 Truss

    NASA Technical Reports Server (NTRS)

    2002-01-01

    KENNEDY SPACE CENTER, FLA. - STS-113 Mission Specialists John Herrington (left) and Michael Lopez-Alegria (right) look over the P1 Integrated Truss Structure, the primary payload for the mission. The P1 truss will be attached to the central truss segment, S0 Truss, during spacewalks. The payload also includes the Crew and Equipment Translation Aid (CETA) Cart B that can be used by spacewalkers to move along the truss with equipment. STS-113 is scheduled to launch Oct. 6, 2002.

  20. STS-113 Mission Specialist Michael Lopez-Alegria looks over the P1 Truss

    NASA Technical Reports Server (NTRS)

    2002-01-01

    KENNEDY SPACE CENTER, FLA. -- STS-113 Mission Specialist Michael Lopez-Alegria looks over the P1 Integrated Truss Structure, the primary payload for the mission. The P1 truss will be attached to the central truss segment, S0 Truss, during spacewalks. The payload also includes the Crew and Equipment Translation Aid (CETA) Cart B that can be used by spacewalkers to move along the truss with equipment. STS-113 is scheduled to launch Oct. 6, 2002.

  1. The P4 truss is moved to a workstand in the SSPF

    NASA Technical Reports Server (NTRS)

    2000-01-01

    After its move across the Space Station Processing Facility, the International Space Station's P4 truss rests in its workstand. Part of the 10-truss, girder-like structure that will ultimately extend the length of a football field, the P4 is the second port truss segment that will attach to the first port truss segment (P1 truss). The P4 is scheduled for mission 12A in September 2002.

  2. STS-112 S1 Truss is transported to the payload canister

    NASA Technical Reports Server (NTRS)

    2002-01-01

    KENNEDY SPACE CENTER, FLA. - Workers inside the payload canister watch the S1 Integrated Truss Structure as it is lowered toward them. The canister will transport the truss to Atlantis. The first starboard truss segment, the S1 will be attached to the Central truss segment, the S0 Truss, on the International Space Station during mission STS-112. Atlantis is scheduled to launch no earlier than Oct. 2.

  3. The challenge of adaptive structures

    NASA Astrophysics Data System (ADS)

    Breitbach, E. J.; Wimmel, R.

    Future lightweight design in space structure technology has to pay more attention to vibration suppression, to position control, or, more generally, to structure-inherent adaptability. These properties are often called "intelligent" or "smart", ignoring the fact that only creatures can have mental abilities. Having adaptation mechanisms for every dynamic process, living nature indeed teaches us that it is inexpedient if technical structural systems dispense with adaptability. Vibration and stability phenomena are making performance restrictions in space systems more and more evident. The DLR project ARES (Actively Reacting Flexible Structures) intends to overcome these limitations by developing a new class of technical systems. The ARES concept essentially consists of two new technologies: new kinds of integrated sensors and actuators working as components lying in the structural load path, and adaptive controllers consisting of digital filters which are adaptive in that they react against changing environmental influences as well as changes within the structure itself.

  4. The Z1 truss is prepped in the PCR for transfer to Discovery's payload bay

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Inside the Payload Changeout Room (PCR), workers prepare to move the Integrated Truss Structure Z1 out of the payload canister. Once inside the PCR, workers will get ready to move the Z1 into the payload bay of Space Shuttle Discovery. The Z1 truss is the first of 10 that will become the backbone of the International Space Station, eventually stretching the length of a football field. Along with its companion payload, the third Pressurized Mating Adapter, the Z1 is scheduled to be launched aboard Discovery Oct. 5 at 9:38 p.m. EDT.

  5. KINEMATIC ANALYSIS OF MODULAR, TRUSS-BASED MANIPULATOR UNITS

    SciTech Connect

    Salerno, R. J.

    1994-06-01

    Decontamination and Dismantling (D&D) activities within the U.S. Department of Energy (DOE) require a long reach manipulator with a large load capacity. Variable Geometry Trusses (VGTs) are a unique class of mechanical structures which allow the advantages of truss structures for large scale applications to be applied to large robotic manipulators. Individual VGT units may be assembled to create a modular, long-reach, truss-type manipulator. Each module of such a manipulator system is either a static truss section or one of several possible VGT geometries. While many potential applications exist for this technology, the present work is largely motivated by the need for generic robotic systems for remote manipulation. A manipulator system based on VGT modules provides several advantages. The reconfigurable nature of the manipulator system allows it to be adapted on site to unforeseen conditions. The kinematic redundancy of the manipulator enables it to work effectively even in a highly obstructed workspace. The parallel structure of the truss modules enables the manipulator to be withdrawn in the event of a structural failure. Finally, the open framework of the modules provides a clear, protected passageway for control and power cabling, waste conveyance, or other services required at the end effector. As is implied in a truss structure, all primary members of a VGT are ideally loaded in pure tension or compression. This results in an extremely stiff and strong manipulator system with minimal overall weight. Careful design of the joints of a VGT is very important to the overall stiffness and accuracy of the structure, as several links (as many as six) are joined together at each joint. The greatest disadvantage to this approach to manipulator design has traditionally been that the kinematics of VGT structures are complex and poorly understood. This report specifically addresses the kinematics of several possible geometries for the individual VGT units. Equations and

  6. Multi-Criterion Preliminary Design of a Tetrahedral Truss Platform

    NASA Technical Reports Server (NTRS)

    Wu, K. Chauncey

    1995-01-01

    An efficient method is presented for multi-criterion preliminary design and demonstrated for a tetrahedral truss platform. The present method requires minimal analysis effort and permits rapid estimation of optimized truss behavior for preliminary design. A 14-m-diameter, 3-ring truss platform represents a candidate reflector support structure for space-based science spacecraft. The truss members are divided into 9 groups by truss ring and position. Design variables are the cross-sectional area of all members in a group, and are either 1, 3 or 5 times the minimum member area. Non-structural mass represents the node and joint hardware used to assemble the truss structure. Taguchi methods are used to efficiently identify key points in the set of Pareto-optimal truss designs. Key points identified using Taguchi methods are the maximum frequency, minimum mass, and maximum frequency-to-mass ratio truss designs. Low-order polynomial curve fits through these points are used to approximate the behavior of the full set of Pareto-optimal designs. The resulting Pareto-optimal design curve is used to predict frequency and mass for optimized trusses. Performance improvements are plotted in frequency-mass (criterion) space and compared to results for uniform trusses. Application of constraints to frequency and mass and sensitivity to constraint variation are demonstrated.

  7. A Practical Monitoring System for the Structural Safety of Mega-Trusses Using Wireless Vibrating Wire Strain Gauges

    PubMed Central

    Park, Hyo Seon; Lee, Hwan Young; Choi, Se Woon; Kim, Yousok

    2013-01-01

    Sensor technologies have been actively employed in structural health monitoring (SHM) to evaluate structural safety. To provide stable and real-time monitoring, a practical wireless sensor network system (WSNS) based on vibrating wire strain gauges (VWSGs) is proposed and applied to a building under construction. In this WSNS, the data measured from each VWSG are transmitted to the sensor node via a signal line and then transmitted to the master node through a short-range wireless communication module (operating on the Industrial, Scientific, and Medical (ISM) band). The master node also employs a long-range wireless communication module (Code Division Multiple Access—CDMA) to transmit the received data from the sensor node to a server located in a remote area, which enables a manager to examine the measured data in real time without any time or location restrictions. In this study, a total of 48 VWSGs, 14 sensor nodes, and seven master nodes were implemented to measure long-term strain variations of mega-trusses in an irregular large-scale building under construction. Based on strain data collected over a 16-month period, a quantitative evaluation of the construction process was performed to determine the aspects that exhibit the greatest influence on member behavior and to conduct a comparison with numerical simulation results. The effect of temperature stress on the structural elements was also analyzed. From these observations, the feasibility of a long-term WSNS based on VWSGs to evaluate the structural safety of an irregular building under construction was confirmed. PMID:24351640

  8. A practical monitoring system for the structural safety of mega-trusses using wireless vibrating wire strain gauges.

    PubMed

    Park, Hyo Seon; Lee, Hwan Young; Choi, Se Woon; Kim, Yousok

    2013-01-01

    Sensor technologies have been actively employed in structural health monitoring (SHM) to evaluate structural safety. To provide stable and real-time monitoring, a practical wireless sensor network system (WSNS) based on vibrating wire strain gauges (VWSGs) is proposed and applied to a building under construction. In this WSNS, the data measured from each VWSG are transmitted to the sensor node via a signal line and then transmitted to the master node through a short-range wireless communication module (operating on the Industrial, Scientific, and Medical (ISM) band). The master node also employs a long-range wireless communication module (Code Division Multiple Access-CDMA) to transmit the received data from the sensor node to a server located in a remote area, which enables a manager to examine the measured data in real time without any time or location restrictions. In this study, a total of 48 VWSGs, 14 sensor nodes, and seven master nodes were implemented to measure long-term strain variations of mega-trusses in an irregular large-scale building under construction. Based on strain data collected over a 16-month period, a quantitative evaluation of the construction process was performed to determine the aspects that exhibit the greatest influence on member behavior and to conduct a comparison with numerical simulation results. The effect of temperature stress on the structural elements was also analyzed. From these observations, the feasibility of a long-term WSNS based on VWSGs to evaluate the structural safety of an irregular building under construction was confirmed. PMID:24351640

  9. P-1 truss arrival at KSC

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Workers oversee the placement of the P-1 truss, a component of the International Space Station, onto a flatbed truck that will move it to the Operations and Checkout Building for processing. The P-1 truss, scheduled to fly in spring of 2002, is part of a total 10-truss, girder-like structure on the Station that will ultimately extend the length of a football field. Astronauts will attach the 14-by-15 foot structure to the port side of the center truss, S0, during the spring assembly flight. The 33,000-pound P- 1 will house the thermal radiator rotating joint (TRRJ) that will rotate the Station's radiators away from the sun to increase their maximum cooling efficiency.

  10. Natural frequency of uniform and optimized tetrahedral truss platforms

    NASA Technical Reports Server (NTRS)

    Wu, K. Chauncey; Lake, Mark S.

    1994-01-01

    Qualitative and quantitative estimates for the fundamental frequency of uniform and optimized tetrahedral truss platforms are determined. A semiempirical equation is developed for the frequency of free-free uniform trusses as a function of member material properties, truss dimensions, and parasitic (nonstructural) mass fraction Mp/Mt. Optimized trusses with frequencies approximately two times those of uniform trusses are determined by varying the cross-sectional areas of member groups. Trusses with 3 to 8 rings, no parasitic mass, and member areas up to 25 times the minimum area are optimized. Frequencies computed for ranges of both Mp/Mt and the ratio of maximum area to minimum area are normalized to the frequency of a uniform truss with no parasitic mass. The normalized frequency increases with the number of rings, and both frequency and the ratio of maximum area to minimum area decrease with increasing Mp/Mt. Frequency improvements that are achievable with a limited number of member areas are estimated for a 3-ring truss by using Taguchi methods. Joint stiffness knockdown effects are also considered. Comparison of optimized and baseline uniform truss frequencies indicates that tailoring can significantly increase structural frequency; maximum gains occur for trusses with low values of Mp/Mt. This study examines frequency trends for ranges of structural parameters and may be used as a preliminary design guide.

  11. Prestressed rock truss

    SciTech Connect

    Johnson, S.F.

    1981-06-23

    A roof support system for mines in which prestressed rock trusses are bolted to the roof of the mine with roof bolts which each extend beyond the width of the mine gallery and the method of installing said trusses into position.

  12. Correlation of predicted and measured thermal stresses on a truss-type aircraft structure

    NASA Technical Reports Server (NTRS)

    Jenkins, J. M.; Schuster, L. S.; Carter, A. L.

    1978-01-01

    A test structure representing a portion of a hypersonic vehicle was instrumented with strain gages and thermocouples. This test structure was then subjected to laboratory heating representative of supersonic and hypersonic flight conditions. A finite element computer model of this structure was developed using several types of elements with the NASA structural analysis (NASTRAN) computer program. Temperature inputs from the test were used to generate predicted model thermal stresses and these were correlated with the test measurements.

  13. 16. Pony trusses pier between the 64 foot truss ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    16. Pony trusses - pier between the 64 foot truss and the first 80 foot truss. View of the lower chord pin connection at the juncture of the two pony trusses as they sit on the replacement pier added, circa 1966. Shows the floor beam, chord eye bars. There are 10 of these similar connections for the six pony trusses. A 1 1/2 conduit is also shown. - Weidemeyer Bridge, Spanning Thomes Creek at Rawson Road, Corning, Tehama County, CA

  14. Model correlation and damage location for large space truss structures: Secant method development and evaluation

    NASA Technical Reports Server (NTRS)

    Smith, Suzanne Weaver; Beattie, Christopher A.

    1991-01-01

    On-orbit testing of a large space structure will be required to complete the certification of any mathematical model for the structure dynamic response. The process of establishing a mathematical model that matches measured structure response is referred to as model correlation. Most model correlation approaches have an identification technique to determine structural characteristics from the measurements of the structure response. This problem is approached with one particular class of identification techniques - matrix adjustment methods - which use measured data to produce an optimal update of the structure property matrix, often the stiffness matrix. New methods were developed for identification to handle problems of the size and complexity expected for large space structures. Further development and refinement of these secant-method identification algorithms were undertaken. Also, evaluation of these techniques is an approach for model correlation and damage location was initiated.

  15. P-1 truss moves into O&C Building

    NASA Technical Reports Server (NTRS)

    2000-01-01

    The P-1 truss, a component of the International Space Station, sits inside the Operations and Checkout Building where it will undergo processing. The truss, scheduled to fly in spring of 2002, is part of a total 10-truss, girder-like structure on the Station that will ultimately extend the length of a football field. Astronauts will attach the 14-by-15 foot structure to the port side of the center truss, S0, during the spring assembly flight. The 33,000-pound P-1 will house the thermal radiator rotating joint (TRRJ) that will rotate the Station's radiators away from the sun to increase their maximum cooling efficiency.

  16. Deployable M-Braced Truss

    NASA Technical Reports Server (NTRS)

    Mikulas, M. M., Jr.; Rhodes, M. D.

    1985-01-01

    Tension/compression and shear separated structurally in deployable beam. M-Braced Sections Packaged using combination of hinges and telescoping sections. When upper sections telescope into base, diagonals hinge, telescope, and rotate along batten. Components of M-braced truss fabricated from conventional metallic materials or nonmetallic materials such as graphite/epoxy. Applications include masts for antenna feed horns and ribs for solar array blankets.

  17. Truss Performance and Packaging Metrics

    NASA Technical Reports Server (NTRS)

    Mikulas, Martin M.; Collins, Timothy J.; Doggett, William; Dorsey, John; Watson, Judith

    2006-01-01

    In the present paper a set of performance metrics are derived from first principals to assess the efficiency of competing space truss structural concepts in terms of mass, stiffness, and strength, for designs that are constrained by packaging. The use of these performance metrics provides unique insight into the primary drivers for lowering structural mass and packaging volume as well as enabling quantitative concept performance evaluation and comparison. To demonstrate the use of these performance metrics, data for existing structural concepts are plotted and discussed. Structural performance data is presented for various mechanical deployable concepts, for erectable structures, and for rigidizable structures.

  18. Adaptive Control For Flexible Structures

    NASA Technical Reports Server (NTRS)

    Bayard, David S.; Ih, Che-Hang Charles; Wang, Shyh Jong

    1988-01-01

    Paper discusses ways to cope with measurement noise in adaptive control system for large, flexible structure in outer space. System generates control signals for torque and thrust actuators to turn all or parts of structure to desired orientations while suppressing torsional and other vibrations. Main result of paper is general theory for introduction of filters to suppress measurement noise while preserving stability.

  19. Development of a truss joint for robotic assembly of space structures

    NASA Technical Reports Server (NTRS)

    Parma, George F.

    1992-01-01

    This report presents the results of a detailed study of mechanical fasteners which were designed to facilitate robotic assembly of structures. Design requirements for robotic structural assembly were developed, taking into account structural properties and overall system design, and four candidate fasteners were designed to meet them. These fasteners were built and evaluated in the laboratory, and the Hammer-Head joint was chosen as superior overall. It had a high reliability of fastening under misalignments of 2.54 mm (0.1 in) and 3 deg, the highest end fixity (2.18), the simplest end effector, an integral capture guide, good visual verification, and the lightest weight (782 g, 1.72 lb). The study found that a good design should incorporate chamfers sliding on chamfers, cylinders sliding on chamfers, and hard surface finishes on sliding surfaces. The study also comments on robot flexibility, sag, hysteresis, thermal expansion, and friction which were observed during the testing.

  20. System identification of a truss type space structure using the multiple boundary condition test (MBCT) method

    NASA Technical Reports Server (NTRS)

    Kuo, C. P.; Wada, B. K.

    1987-01-01

    Experimental results on the application of the multiple boundary condition test (MBCT) method to experimental hardware have validated its usefulness in the ground testing of large flexible space structures. Excellant results were obtained with a beam with a uniform cross-section and with a beam consisting of two different cross-sections alternately located. The MBCT method is then applied to a 12 bay MAST type structure which is part of the NASA COFS program, and the cross-sectional area of the updated mathematical model was found to be within 4.5 percent of the true value.

  1. Truss Optimization for a Manned Nuclear Electric Space Vehicle using Genetic Algorithms

    NASA Technical Reports Server (NTRS)

    Benford, Andrew; Tinker, Michael L.

    2004-01-01

    The purpose of this paper is to utilize the genetic algorithm (GA) optimization method for structural design of a nuclear propulsion vehicle. Genetic algorithms provide a guided, random search technique that mirrors biological adaptation. To verify the GA capabilities, other traditional optimization methods were used to generate results for comparison to the GA results, first for simple two-dimensional structures, and then for full-scale three-dimensional truss designs.

  2. Minimizing distortion and internal forces in truss structures by simulated annealing

    NASA Technical Reports Server (NTRS)

    Kincaid, Rex K.; Padula, Sharon L.

    1990-01-01

    Inaccuracies in the length of members and the diameters of joints of large space structures may produce unacceptable levels of surface distortion and internal forces. Here, two discrete optimization problems are formulated, one to minimize surface distortion (DSQRMS) and the other to minimize internal forces (FSQRMS). Both of these problems are based on the influence matrices generated by a small-deformation linear analysis. Good solutions are obtained for DSQRMS and FSQRMS through the use of a simulated annealing heuristic.

  3. 29. 100 foot through truss looking north from the ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    29. 100 foot through truss - looking north from the deck through the south portal of the first through truss, to show the general configuration of the upper part of the structure. - Weidemeyer Bridge, Spanning Thomes Creek at Rawson Road, Corning, Tehama County, CA

  4. 32. 100 foot through truss looking north from the ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    32. 100 foot through truss - looking north from the deck through the exit portal of the second through truss, showing the general arrangement of the underside of the upper part of the structure. - Weidemeyer Bridge, Spanning Thomes Creek at Rawson Road, Corning, Tehama County, CA

  5. Detail of tension bars at end posts western truss. Shows ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Detail of tension bars at end posts western truss. Shows adjustable bars at top of structure; diagonal and vertical members on truss are not adjustable. Looking north from civilian land. - Naval Supply Annex Stockton, Rough & Ready Island, Stockton, San Joaquin County, CA

  6. Detail of tension bars at end posts western truss. Shows ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Detail of tension bars at end posts western truss. Shows adjustable bars at top of structure; diagonal and vertical members on truss are not adjustable. Looking north from civilian land. - Naval Supply Annex Stockton, Daggett Road Bridge, Daggett Road traversing Burns Cut Off, Stockton, San Joaquin County, CA

  7. STS-112 S1 truss in Payload Changeout Room at Launch Pad 39-B

    NASA Technical Reports Server (NTRS)

    2002-01-01

    KENNEDY SPACE CENTER, FLA. -- The payload canister is ready to be opened in the Payload Changeout Room at the pad. Inside is the S1 Integrated Truss Structure, primary payload on mission STS-112 aboard Space Shuttle Atlantis. The first starboard truss segment, the S1 will be attached to the Central truss segment, the S0 Truss, on the International Space Station during the mission. Atlantis is scheduled to launch no earlier than Oct. 2.

  8. STS-112 S1 Truss is transported to the payload canister

    NASA Technical Reports Server (NTRS)

    2002-01-01

    KENNEDY SPACE CENTER, FLA. -- An overhead crane lifts the S1 Integrated Truss Structure from its workstand. The S1 will be placed in the payload canister for transport it to Atlantis. The first starboard truss segment, the S1 will be attached to the Central truss segment, the S0 Truss, on the International Space Station during mission STS-112. Atlantis is scheduled to launch no earlier than Oct. 2.

  9. STS-112 S1 Truss is transported to the payload canister

    NASA Technical Reports Server (NTRS)

    2002-01-01

    KENNEDY SPACE CENTER, FLA. -- An overhead crane moves the S1 Integrated Truss Structure above over other equipment to get to the payload canister for transport to Atlantis. The first starboard truss segment, the S1 will be attached to the Central truss segment, the S0 Truss, on the International Space Station during mission STS-112. Atlantis is scheduled to launch no earlier than Oct. 2.

  10. 3D Structured Grid Adaptation

    NASA Technical Reports Server (NTRS)

    Banks, D. W.; Hafez, M. M.

    1996-01-01

    Grid adaptation for structured meshes is the art of using information from an existing, but poorly resolved, solution to automatically redistribute the grid points in such a way as to improve the resolution in regions of high error, and thus the quality of the solution. This involves: (1) generate a grid vis some standard algorithm, (2) calculate a solution on this grid, (3) adapt the grid to this solution, (4) recalculate the solution on this adapted grid, and (5) repeat steps 3 and 4 to satisfaction. Steps 3 and 4 can be repeated until some 'optimal' grid is converged to but typically this is not worth the effort and just two or three repeat calculations are necessary. They also may be repeated every 5-10 time steps for unsteady calculations.

  11. P-1 truss moved to O&C Building

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Cranes place the P-1 truss, a component of the International Space Station, on a transport vehicle that will move it to the Operations and Checkout Building for processing. The truss had been temporarily stored in the RLV hangar in the background as a precaution against approaching bad weather. The P-1 truss, scheduled to fly in spring of 2002, is part of a total 10-truss, girder-like structure on the Station that will ultimately extend the length of a football field. Astronauts will attach the 14-by- 15 foot structure to the port side of the center truss, S0, during the spring assembly flight. The 33,000-pound P-1 will house the thermal radiator rotating joint (TRRJ) that will rotate the Station's radiators away from the sun to increase their maximum cooling efficiency.

  12. Experimental characterization of deployable trusses and joints

    NASA Technical Reports Server (NTRS)

    Ikegami, R.; Church, S. M.; Keinholz, D. A.; Fowler, B. L.

    1987-01-01

    The structural dynamic properties of trusses are strongly affected by the characteristics of joints connecting the individual beam elements. Joints are particularly significant in that they are often the source of nonlinearities and energy dissipation. While the joints themselves may be physically simple, direct measurement is often necessary to obtain a mathematical description suitable for inclusion in a system model. Force state mapping is a flexible, practical test method for obtaining such a description, particularly when significant nonlinear effects are present. It involves measurement of the relationship, nonlinear or linear, between force transmitted through a joint and the relative displacement and velocity across it. An apparatus and procedure for force state mapping are described. Results are presented from tests of joints used in a lightweight, composite, deployable truss built by the Boeing Aerospace Company. The results from the joint tests are used to develop a model of a full 4-bay truss segment. The truss segment was statically and dynamically tested. The results of the truss tests are presented and compared with the analytical predictions from the model.

  13. Comparative morphology of configurations with reduced part count derived from the octahedral-tetrahedral truss

    NASA Technical Reports Server (NTRS)

    Lalvani, Haresh; Collins, Timothy J.

    1991-01-01

    Morphology (the study of structure and form) of the octahedral-tetrahedral (octet) truss is described. Both the geometry and symmetry of the octet truss are considered. Morphological techniques based on symmetry operations are presented which enable the derivation of reduced-part-count truss configurations from the octet truss by removing struts and nodes. These techniques are unique because their Morphological origination and they allow for the systematic generation and analysis of a large variety of structures. Methods for easily determining the part count and redundancy of infinite truss configurations are presented. Nine examples of truss configurations obtained by applying the derivation techniques are considered. These configurations are structurally stable while at the same time exhibiting significant reductions in part count. Some practical and analytical considerations, such as structural performance, regarding the example reduced-part-count truss geometries are briefly discussed.

  14. STS-110 payload S0 Truss is moved to payload canister in O&C

    NASA Technical Reports Server (NTRS)

    2002-01-01

    KENNEDY SPACE CENTER, FLA. -- In the Operations and Checkout Building, an overhead crane carries the Integrated Truss Structure S0 from its workstand toward the payload canister. The S0 truss will be transported to the launch pad for mission STS-110. Part of the payload, the S0 truss will become the backbone of the orbiting International Space Station (ISS), at the center of the 10-truss, girderlike structure that will ultimately extend the length of a football field on the ISS. The S0 truss will be attached to the U.S. Lab, 'Destiny,' on the 11-day mission. Launch is scheduled for April 4.

  15. Analysis of Brace Stiffness Influence on Stability of the Truss

    NASA Astrophysics Data System (ADS)

    Krajewski, M.; Iwicki, P.

    2015-02-01

    The paper is devoted to the numerical and experimental research of stability of a truss with side elastic supports at the top chord. The structure is a model of a real roof truss scaled by factor 1/4. The linear buckling analysis and non-linear static analysis were carried out. The buckling length factor for the compressed top chord was calculated and the limit load for the imperfect truss shell model with respect to brace stiffness was obtained. The relation between brace normal force and loading of the truss is presented. The threshold stiffness of braces necessary to obtain the maximum buckling load was found. The truss load bearing capacity obtained from numerical analysis was compared with Eurocode 3 requirements.

  16. 13. TOP OF STATIC TEST TOWER VIEW OF STEEL TRUSS ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    13. TOP OF STATIC TEST TOWER VIEW OF STEEL TRUSS STRUCTURE AND OVERHEAD CRANE. - Marshall Space Flight Center, Saturn Propulsion & Structural Test Facility, East Test Area, Huntsville, Madison County, AL

  17. STS-113 Mission Specialists review data on the P1 Truss

    NASA Technical Reports Server (NTRS)

    2002-01-01

    KENNEDY SPACE CENTER, FLA. - STS-113 Mission Specialists Michael Lopez-Alegria (left) and John Herrington (center) review data on the P1 Integrated Truss Structure with a technician in the Space Station Processing Facility. During the mission, the P1 truss will be attached to the central truss segment, S0 Truss, during spacewalks. The payload also includes the Crew and Equipment Translation Aid (CETA) Cart B that can be used by spacewalkers to move along the truss with equipment. STS-113 is scheduled to launch Oct. 6, 2002.

  18. The P4 truss is moved to a workstand in the SSPF

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Suspended by an overhead crane in the Space Station Processing Facility, the International Space Station's P4 truss moves toward a workstand. Below and behind it on the floor is the Multi- Purpose Logistics Module Raffaello, another segment of the Space Station. Part of the 10-truss, girder-like structure that will ultimately extend the length of a football field, the P4 is the second port truss segment that will attach to the first port truss segment (P1 truss). The P4 is scheduled for mission 12A in September 2002.

  19. International Space Station Sports a New Truss

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This close-up view of the International Space Station (ISS), newly equipped with its new 27,000-pound S0 (S-zero) truss, was photographed by an astronaut aboard the Space Shuttle Atlantis STS-110 during its ISS flyaround mission while pulling away from the ISS. The STS-110 mission prepared the Station for future spacewalks by installing and outfitting the 43-foot-long S0 truss and preparing the first railroad in space, the Mobile Transporter. The 27,000 pound S0 truss was the first of 9 segments that will make up the Station's external framework that will eventually stretch 356 feet (109 meters), or approximately the length of a football field. This central truss segment also includes a flatcar called the Mobile Transporter and rails that will become the first 'space railroad,' which will allow the Station's robotic arm to travel up and down the finished truss for future assembly and maintenance. The completed truss structure will hold solar arrays and radiators to provide power and cooling for additional international research laboratories from Japan and Europe that will be attached to the Station. STS-110 Extravehicular Activity (EVA) marked the first use of the Station's robotic arm to maneuver spacewalkers around the Station and was the first time all of a shuttle crew's spacewalks were based out of the Station's Quest Airlock. It was also the first Shuttle to use three Block II Main Engines. The Space Shuttle Orbiter Atlantis STS-110 mission, was launched April 8, 2002 and returned to Earth April 19, 2002.

  20. International Space Station Sports a New Truss

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This close-up view of the International Space Station (ISS), newly equipped with its new 27,000- pound S0 (S-zero) truss, was photographed by an astronaut aboard the Space Shuttle Atlantis STS-110 mission following its undocking from the ISS. The STS-110 mission prepared the Station for future spacewalks by installing and outfitting the 43-foot-long S0 truss and preparing the first railroad in space, the Mobile Transporter. The 27,000 pound S0 truss was the first of 9 segments that will make up the Station's external framework that will eventually stretch 356 feet (109 meters), or approximately the length of a football field. This central truss segment also includes a flatcar called the Mobile Transporter and rails that will become the first 'space railroad,' which will allow the Station's robotic arm to travel up and down the finished truss for future assembly and maintenance. The completed truss structure will hold solar arrays and radiators to provide power and cooling for additional international research laboratories from Japan and Europe that will be attached to the Station. STS-110 Extravehicular Activity (EVA) marked the first use of the Station's robotic arm to maneuver spacewalkers around the Station and was the first time all of a shuttle crew's spacewalks were based out of the Station's Quest Airlock. It was also the first Shuttle to use three Block II Main Engines. The Space Shuttle Orbiter Atlantis STS-110 mission, was launched April 8, 2002 and returned to Earth April 19, 2002.

  1. International Space Station Sports a New Truss

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This close-up view of the International Space Station (ISS), newly equipped with its new 27,000-pound S0 (S-zero) truss, was photographed by an astronaut aboard the Space Shuttle Atlantis STS-110 upon its ISS flyaround mission while pulling away from the ISS. The STS-110 mission prepared the Station for future spacewalks by installing and outfitting the 43-foot-long S0 truss and preparing the first railroad in space, the Mobile Transporter. The 27,000 pound S0 truss was the first of 9 segments that will make up the Station's external framework that will eventually stretch 356 feet (109 meters), or approximately the length of a football field. This central truss segment also includes a flatcar called the Mobile Transporter and rails that will become the first 'space railroad,' which will allow the Station's robotic arm to travel up and down the finished truss for future assembly and maintenance. The completed truss structure will hold solar arrays and radiators to provide power and cooling for additional international research laboratories from Japan and Europe that will be attached to the Station. STS-110 Extravehicular Activity (EVA) marked the first use of the Station's robotic arm to maneuver spacewalkers around the station and was the first time all of a Shuttle crew's spacewalks were based out of the Station's Quest Airlock. It was also the first Shuttle to use three Block II Main Engines. The Space Shuttle Orbiter Atlantis STS-110 mission, was launched April 8, 2002 and returned to Earth April 19, 2002.

  2. International Space Station Sports a New Truss

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This close-up view of the International Space Station (ISS), newly equipped with its new 27,000-pound S0 (S-zero) truss, was photographed by an astronaut aboard the Space Shuttle Atlantis STS-110 mission following its undocking from the ISS. The STS-110 mission prepared the Station for future spacewalks by installing and outfitting the 43-foot-long S0 truss and preparing the first railroad in space, the Mobile Transporter. The 27,000 pound S0 truss was the first of 9 segments that will make up the Station's external framework that will eventually stretch 356 feet (109 meters), or approximately the length of a football field. This central truss segment also includes a flatcar called the Mobile Transporter and rails that will become the first 'space railroad,' which will allow the Station's robotic arm to travel up and down the finished truss for future assembly and maintenance. The completed truss structure will hold solar arrays and radiators to provide power and cooling for additional international research laboratories from Japan and Europe that will be attached to the Station. STS-110 Extravehicular Activity (EVA) marked the first use of the Station's robotic arm to maneuver spacewalkers around the Station and was the first time all of a Shuttle crew's spacewalks were based out of the Station's Quest Airlock. It was also the first Shuttle to use three Block II Main Engines. The Space Shuttle Orbiter Atlantis STS-110 mission, was launched April 8, 2002 and returned to Earth April 19, 2002.

  3. International Space Station Sports a New Truss

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This close-up view of the International Space Station (ISS), newly equipped with its new 27,000-pound S0 (S-zero) truss, was photographed by an astronaut aboard the Space Shuttle Atlantis STS-110 during its ISS flyaround mission while pulling away from the ISS. The STS-110 mission prepared the Station for future spacewalks by installing and outfitting the 43-foot-long S0 truss and preparing the first railroad in space, the Mobile Transporter. The 27,000-pound S0 truss was the first of 9 segments that will make up the Station's external framework that will eventually stretch 356 feet (109 meters), or approximately the length of a football field. This central truss segment also includes a flatcar called the Mobile Transporter and rails that will become the first 'space railroad,' which will allow the Station's robotic arm to travel up and down the finished truss for future assembly and maintenance. The completed truss structure will hold solar arrays and radiators to provide power and cooling for additional international research laboratories from Japan and Europe that will be attached to the Station. STS-110 Extravehicular Activity (EVA) marked the first use of the Station's robotic arm to maneuver spacewalkers around the Station and was the first time all of a Shuttle crew's spacewalks were based out of the Station's Quest Airlock. It was also the first Shuttle to use three Block II Main Engines. The Space Shuttle Orbiter Atlantis STS-110 mission, was launched April 8, 2002 and returned to Earth April 19, 2002.

  4. Two pass method and radiation interchange processing when applied to thermal-structural analysis of large space truss structures

    NASA Technical Reports Server (NTRS)

    Warren, Andrew H.; Arelt, Joseph E.; Lalicata, Anthony L.; Rogers, Karen M.

    1993-01-01

    A method of efficient and automated thermal-structural processing of very large space structures is presented. The method interfaces the finite element and finite difference techniques. It also results in a pronounced reduction of the quantity of computations, computer resources and manpower required for the task, while assuring the desired accuracy of the results.

  5. The P-1 truss in the O&C

    NASA Technical Reports Server (NTRS)

    2000-01-01

    In the foreground is the P-1 truss, resting in a blue workstand in the long, crowded Operations and Checkout Building. Scheduled to fly in spring of 2002, the P-1 is part of a total 10-truss, girder-like structure that will ultimately extend the length of a football field. Astronauts will attach the 14- by 15-foot structure to the port side of the center truss, S0, during the spring assembly flight. The 33,000-pound P-1 will house the thermal radiator rotating joint (TRRJ) that will rotate the International Space Station's radiators away from the sun to increase their maximum cooling efficiency.

  6. 48. REMOVAL OF FIRST TRUSS. The first truss removed here ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    48. REMOVAL OF FIRST TRUSS. The first truss removed here rests on ground plates and awaits the similar placement of all the trusses for temporary storage. In the foreground are cut out sections of roofing also removed by crane. Note the 1873-74 standing seam sheet metal roof above the 1851 shingling. The roof pole gutters were in part made up of bench back rails. - Twelfth Street Meeting House, 20 South Twelfth Street, Philadelphia, Philadelphia County, PA

  7. Wave propagation in equivalent continuums representing truss lattice materials

    SciTech Connect

    Messner, Mark C.; Barham, Matthew I.; Kumar, Mukul; Barton, Nathan R.

    2015-07-29

    Stiffness scales linearly with density in stretch-dominated lattice meta-materials offering the possibility of very light yet very stiff structures. Current additive manufacturing techniques can assemble structures consisting of these lattice materials, but the design of such structures will require accurate, efficient simulation techniques. Equivalent continuum models have several advantages over discrete truss models of stretch dominated lattices, including computational efficiency and ease of model construction. However, the development an equivalent model suitable for representing the dynamic response of a periodic truss is complicated by microinertial effects. This paper derives a dynamic equivalent continuum model for periodic truss structures and verifies it against detailed finite element simulations. The model must incorporate microinertial effects to accurately reproduce long-wavelength characteristics of the response such as anisotropic elastic soundspeeds. The formulation presented here also improves upon previous work by preserving equilibrium at truss joints for affine lattice deformation and by improving numerical stability by eliminating vertices in the effective yield surface.

  8. Changing Stiffnesses Of Truss Members For Vibration Tests

    NASA Technical Reports Server (NTRS)

    Wada, Ben K.

    1994-01-01

    Extension of active-member method of vibration testing of trusses and similar structures proposed to obtain additional data for refinement of finite-element mathematical models of vibrational properties of structures. Active truss members not only used in vibration tests to excite and measure vibrations of structures, but also made to have different effective stiffnesses in some tests, enabling excitation of different vibrational modes yielding additional data. Aspects of active-member method of vibration testing described previously in articles in NASA Tech Briefs including "Two Techniques for Suppressing Vibrations in Structures" (NPO-17889), "Active Suppression of Vibrations in a Truss" (NPO-18305), and "Active Members Excite and Measure Vibrations in Trusses" (NPO-18353).

  9. 7. DETAIL OF DECK TRUSS SPANNING CANAL. THIS DECK TRUSS ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    7. DETAIL OF DECK TRUSS SPANNING CANAL. THIS DECK TRUSS WA ALSO ERECTED IN 1893 AS PART OF AN EXTENSIVE RECONSTRUCTION OF THE BRIDGE. LOOKING NORTHEAST FROM SOUTH SIDE OF CANAL. - Illinois Central Railroad, Illinois River Bridge, Spanning Illinois River, La Salle, La Salle County, IL

  10. 63. DETAIL OF TRAVELING CRANE TRUSS FROM NORTHEAST. TRUSS IS ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    63. DETAIL OF TRAVELING CRANE TRUSS FROM NORTHEAST. TRUSS IS IN FRONT OF CRUSHED OXIDIZED ORE BIN. THE BARREN SOLUTION TANK IS JUST VISIBLE IN RIGHT BACKGROUND. - Bald Mountain Gold Mill, Nevada Gulch at head of False Bottom Creek, Lead, Lawrence County, SD

  11. Hybrid deployable support truss designs for LDR

    NASA Technical Reports Server (NTRS)

    Hedgepeth, J.

    1988-01-01

    Concepts for a 20-meter diameter Large Deployable Reflector (LDR) deployable truss backup structure, and analytical predictions of its structural characteristics are discussed. The concept shown is referred to as the SIXPAC; It is a combination of the PACTRUSS concept and a single-fold beam, which would make up the desired backup structure. One advantage of retaining the PACTRUSS concept is its packaging density and its capability for synchronous deployment. Various 2-meter hexagonal panel arrangements are possible for this Hybrid PACTRUSS structure depending on the panel-to-structure attachment strategies used. Static analyses of the SIXPAC using various assumptions for truss designs and panel masses of 10 kg sq meters were performed to predict the tip displacement of the structure when supported at the center. The tip displacement ranged from 0.20 to 0.44 mm without the panel mass, and from 0.9 to 3.9 mm with the panel mass (in a 1-g field). The data indicate that the structure can be adequately ground tested to validate its required performance in space, assuming the required performance in space is approximately 100 microns. The static displacement at the tip of the structure when subjected to an angular acceleration of 0.001 rad/sec squared were estimated to range from 0.8 to 7.5 microns, depending on the type of truss elements.

  12. P-1 truss arrives at O&C Building

    NASA Technical Reports Server (NTRS)

    2000-01-01

    The P-1 truss, a component of the International Space Station, arrives in the parking lot outside the Operations and Checkout Building where it will undergo processing. The P-1 truss, scheduled to fly in spring of 2002, is part of a total 10-truss, girder-like structure on the Space Station that will ultimately extend the length of a football field. Astronauts will attach the 14-by-15 foot structure to the port side of the center truss, S0, during the spring assembly flight. The 33,000-pound P-1 will house the thermal radiator rotating joint (TRRJ) that will rotate the Station's radiators away from the sun to increase their maximum cooling efficiency.

  13. P-1 truss moved to O&C Building

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Workers oversee the placement of the P-1 truss, a component of the International Space Station, onto the bed of a transport vehicle that will move it to the Operations and Checkout Building for processing. The P-1 truss, scheduled to fly in spring of 2002, is part of a total 10-truss, girder-like structure on the Station that will ultimately extend the length of a football field. Astronauts will attach the 14-by-15 foot structure to the port side of the center truss, S0, during the spring assembly flight. The 33,000-pound P-1 will house the thermal radiator rotating joint (TRRJ) that will rotate the Station's radiators away from the sun to increase their maximum cooling efficiency.

  14. Design and Synthesis of Triangulated DNA Origami Trusses.

    PubMed

    Matthies, Michael; Agarwal, Nayan P; Schmidt, Thorsten L

    2016-03-01

    DNA nanotechnology offers unique control over matter on the nanoscale. Here, we extend the DNA origami method to cover a range of wireframe truss structures composed of equilateral triangles, which use less material per volume than standard multiple-helix bundles. From a flat truss design, we folded tetrahedral, octahedral, or irregular dodecahedral trusses by exchanging few connector strands. Other than standard origami designs, the trusses can be folded in low-salt buffers that make them compatible with cell culture buffers. The structures also have defined cavities that may in the future be used to precisely position functional elements such as metallic nanoparticles or enzymes. Our graph routing program and a simple design pipeline will enable other laboratories to make use of this valuable and potent new construction principle for DNA-based nanoengineering. PMID:26883285

  15. STS-110 S0 Truss in O&C building ready for launch

    NASA Technical Reports Server (NTRS)

    2002-01-01

    KENNEDY SPACE CENTER, FLA. - In the Operations and Checkout Building, the Integrated Truss Structure S0 is ready for transport to the launch pad on mission STS-110. Scheduled for launch April 4, the 11-day mission will feature Space Shuttle Atlantis docking with the International Space Station (ISS) and delivering the S0 truss, the centerpiece-segment of the primary truss structure that will eventually extend over 300 feet.

  16. Dynamic adaptivity of "smart" piezoelectric structures

    NASA Astrophysics Data System (ADS)

    Tzou, Horn-Sen; Zhong, Jianping P.

    1990-10-01

    Active smart" space and machine structures with adaptive dynamic characteristics have long been interested in a variety of high-performance systems, e.g., flexible robots, flexible space structures, "smart" machines, etc. In this paper, an active adaptive structure made of piezoelectric materials is proposed and evaluated. The structural adaptivity is achieved by a voltage feedback (open or closed loops) utilizing the converse piezoelectric effect. A mathematical model is proposed and the electrodynamic equations of motion and the generalized boundary conditions of a generic piezoelectric shell subjected to mechanical and electrical excitations are derived using Hamilton's principle and the linear piezoelectric theory. The dynamic adaptivity of the structure is introduced using a feedback control system. The theory is demonstrated in a case study in which the structural adaptivity (natural frequency) is investigated.

  17. STS-110 payload S0 Truss is moved to payload canister in O&C

    NASA Technical Reports Server (NTRS)

    2002-01-01

    KENNEDY SPACE CENTER, FLA. -- In the Operations and Checkout Building, the Integrated Truss Structure S0 is ready to be moved to the payload canister for transport to the launch pad for mission STS-110. Part of the payload, the S0 truss will become the backbone of the orbiting International Space Station (ISS), at the center of the 10-truss, girderlike structure that will ultimately extend the length of a football field on the ISS. The S0 truss will be attached to the U.S. Lab, 'Destiny,' on the 11-day mission. Launch is scheduled for April 4.

  18. Fluidic origami: a plant-inspired adaptive structure with shape morphing and stiffness tuning

    NASA Astrophysics Data System (ADS)

    Li, Suyi; Wang, K. W.

    2015-10-01

    Inspired by the physics behind the rapid plant movements and the rich topologies in origami folding, this research creates a unique class of multi-functional adaptive structure through exploring the innovation of fluidic origami. The idea is to connect multiple Miura folded sheets along their crease lines into a space-filling structure, and fill the tubular cells in-between with working fluids. The pressure and fluid flow in these cells can be strategically controlled much like in plants for nastic movements. The relationship between the internal fluid volume and the overall structure deformation is primarily determined by the kinematics of folding. This relationship can be exploited so that fluidic origami can achieve actuation/morphing by actively changing the internal fluid volume, and stiffness tuning by constraining the fluid volume. In order to characterize the working principles and performance potentials of these two adaptive functions, this research develops an equivalent truss frame model on a fluidic origami unit cell to analyze its fundamental elastic characteristics. Eigen-stiffness analysis based on this model reveals the primary modes of deformation and their relationships with initial folding configurations. Performances of the adaptive functions are correlated to the crease pattern design. In parallel to analytical studies, the feasibility of the morphing and stiffness tuning is also examined experimentally via a 3D printed multi-material prototype demonstrator. The research reported in this paper could lead to the synthesis of adaptive fluidic origami cellular metastructures or metamaterial systems for various engineering applications.

  19. STS-110 payload S0 Truss is lifted into payload changeout room

    NASA Technical Reports Server (NTRS)

    2002-01-01

    KENNEDY SPACE CENTER, FLA. -- The payload canister with the S0 Integrated Truss Structure arrives at the launch pad for transfer to Space Shuttle Atlantis's payload bay. Part of the payload on mission STS-110, the S0 truss will become the backbone of the orbiting International Space Station (ISS). The S0 truss will be attached to the U.S. Lab, 'Destiny,' on the 11-day mission. Launch is scheduled for April 4.

  20. Fatigue analysis of mini-mast space truss

    NASA Technical Reports Server (NTRS)

    Hwang, Shoi Y.

    1989-01-01

    The functional, structural adequacy of a 20 meter long generic space truss (Mini-Mast), subjected to fatigue loading, was examined with respect to the failure modes which are most likely to occur during services. The space truss is made of thin-walled tubes having unidirectional, zero degree layups of Celanese G50 graphite fibers/Narmco 5217 epoxy composites. The approach used to investigate the most probable failure mode of the truss under fatigue loading is to determine the stress level, including the types of stress, in the member first, then followed by failure mode analysis based on the stress level just determined. To begin, an approximate beam-parameter truss (BPT) model is analyzed first, followed by a detailed analysis of the truss using a finite element model (FEM) run with NASTRAN code. The response results of the BPT model are used to compare FEM results and to check any major deviation of trend derived from the FEM. The purpose of the work was to search available fatigue data of the tube material, to conduct approximate dynamical stress analysis of the BPT model, to run detailed dynamical stress analysis of the FEM model using NASTRAN code, and to predict the fatigue life of the truss member based on limited fatigue data.

  1. STS-112 S1 truss in Payload Changeout Room at Launch Pad 39-B

    NASA Technical Reports Server (NTRS)

    2002-01-01

    KENNEDY SPACE CENTER, FLA. -- In the Payload Changeout Room at the pad, the payload is moved out of the payload canister for transfer to Space Shuttle Atlantis' payload bay for mission STS-112. The primary payload on the mission is the S1 Integrated Truss Structure. The first starboard truss segment, the S1 will be attached to the Central truss segment, the S0 Truss, on the International Space Station during the mission. Atlantis is scheduled to launch no earlier than Oct. 2.

  2. STS-110 payload S0 Truss in Payload Changeout Room at LC-39A

    NASA Technical Reports Server (NTRS)

    2002-01-01

    KENNEDY SPACE CENTER, FLA. - In the payload changeout room, workers watch as the doors of the payload canister open to reveal the S0 Integrated Truss Structure. The truss will be moved into the PCR and then transferred to Space Shuttle Atlantis's payload bay. Part of the payload on mission STS-110, the S0 truss will become the backbone of the orbiting International Space Station (ISS). The S0 truss will be attached to the U.S. Lab, 'Destiny,' on the 11-day mission. Launch is scheduled for April 4.

  3. STS-110 payload S0 Truss is moved to payload canister in O&C

    NASA Technical Reports Server (NTRS)

    2002-01-01

    KENNEDY SPACE CENTER, FLA. -- In the Operations and Checkout Building, an overhead crane carries the Integrated Truss Structure S0 to the payload canister which will transport it to the launch pad for mission STS-110. Seen below the truss is the Multi-Purpose Logistics Module Donatello, currently not in use. The S0 truss will be part of the payload on Space Shuttle Atlantis. The S0 truss will be attached to the U.S. Lab, 'Destiny,' on the 11-day mission, becoming the backbone of the orbiting International Space Station (ISS). Launch is scheduled for April 4.

  4. Telerobotic truss assembly

    NASA Technical Reports Server (NTRS)

    Sheridan, Philip L.

    1987-01-01

    The ACCESS truss was telerobotically assembled in order to gain experience with robotic assembly of hardware designed for astronaut extravehicular (EVA) assembly. Tight alignment constraints of the ACCESS hardware made telerobotic assembly difficult. A wider alignment envelope and a compliant end effector would have reduced the problem. The manipulator had no linear motion capability, but many of the assembly operations required straight line motion. The manipulator was attached to a motion table in order to provide the X, Y, and Z translations needed. A programmable robot with linear translation capability would have eliminated the need for the motion table and streamlined the assembly. Poor depth perception was a major problem. Shaded paint schemes and alignment lines were helpful in reducing this problem. The four cameras used worked well for only some operations. It was not possible to identify camera locations that worked well for all assembly steps. More cameras or movable cameras would have simplified some operations. The audio feedback system was useful.

  5. An articulated-truss space crane concept

    NASA Technical Reports Server (NTRS)

    Sutter, Thomas R.; Bush, Harold G.; Wallsom, Richard E.

    1990-01-01

    An articulated-truss space-crane concept is described, and four articulating-joint (AJ) concepts are evaluated. The space-crane concept uses the same truss structure hardware as Space Station Freedom. The joint concepts are compared according to their actuator stroke ratio, actuator authority, and part count. One AJ concept is selected as a candidate space-crane joint because of its better performance and lower part count. The space-crane reach envelope is determined as a function of the number of AJs and the number of fixed-length booms. A space crane with three booms, three AJs, and one rotary joint provides an adequate reach envelope for an expected work area. The space-crane tip velocity, because of an allowable truss strut compressive load, is limited to approximately 1.0 in./sec for a 300,000-lbm payload. The displacement response is also shown for an emergency stop scenario as a function of the payload mass. The space-crane tip deflection is on the order of 12 in. for a 300,000-lbm payload.

  6. Rod shop, roof and truss detail showing older pink roof ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Rod shop, roof and truss detail showing older pink roof truss, newer pratt truss, and longitudinal, truss for overhead traveling crane - Chicago, Burlington & Quincy Railroad, Roundhouse & Shops, Broadway & Spring Streets, Aurora, Kane County, IL

  7. Aeroelastic Analysis of SUGAR Truss-Braced Wing Wind-Tunnel Model Using FUN3D and a Nonlinear Structural Model

    NASA Technical Reports Server (NTRS)

    Bartels, Robert E.; Scott, Robert C.; Allen, Timothy J.; Sexton, Bradley W.

    2015-01-01

    Considerable attention has been given in recent years to the design of highly flexible aircraft. The results of numerous studies demonstrate the significant performance benefits of strut-braced wing (SBW) and trussbraced wing (TBW) configurations. Critical aspects of the TBW configuration are its larger aspect ratio, wing span and thinner wings. These aspects increase the importance of considering fluid/structure and control system coupling. This paper presents high-fidelity Navier-Stokes simulations of the dynamic response of the flexible Boeing Subsonic Ultra Green Aircraft Research (SUGAR) truss-braced wing wind-tunnel model. The latest version of the SUGAR TBW finite element model (FEM), v.20, is used in the present simulations. Limit cycle oscillations (LCOs) of the TBW wing/strut/nacelle are simulated at angle-of-attack (AoA) values of -1, 0 and +1 degree. The modal data derived from nonlinear static aeroelastic MSC.Nastran solutions are used at AoAs of -1 and +1 degrees. The LCO amplitude is observed to be dependent on AoA. LCO amplitudes at -1 degree are larger than those at +1 degree. The LCO amplitude at zero degrees is larger than either -1 or +1 degrees. These results correlate well with both wind-tunnel data and the behavior observed in previous studies using linear aerodynamics. The LCO onset at zero degrees AoA has also been computed using unloaded v.20 FEM modes. While the v.20 model increases the dynamic pressure at which LCO onset is observed, it is found that the LCO onset at and above Mach 0.82 is much different than that produced by an earlier version of the FEM, v. 19.

  8. Ground test validation of large precision structure through adaptive structures

    NASA Technical Reports Server (NTRS)

    Wada, Ben K.

    1992-01-01

    Without novel ground validation test (GVT) approaches for such space structures as those contemplated for an orbiting optical interferometer, this and other NASA missions will be stillborn. One such approach may involve the integration of adaptive structures concepts into initial structural designs, in order to accommodate GVT, as well as to allow for redundancy and enhance mission reliability. Adaptive structures are noted to intrinsically relax GVT requirements.

  9. A modular approach to adaptive structures.

    PubMed

    Pagitz, Markus; Pagitz, Manuel; Hühne, Christian

    2014-01-01

    A remarkable property of nastic, shape changing plants is their complete fusion between actuators and structure. This is achieved by combining a large number of cells whose geometry, internal pressures and material properties are optimized for a given set of target shapes and stiffness requirements. An advantage of such a fusion is that cell walls are prestressed by cell pressures which increases, decreases the overall structural stiffness, weight. Inspired by the nastic movement of plants, Pagitz et al (2012 Bioinspir. Biomim. 7) published a novel concept for pressure actuated cellular structures. This article extends previous work by introducing a modular approach to adaptive structures. An algorithm that breaks down any continuous target shapes into a small number of standardized modules is presented. Furthermore it is shown how cytoskeletons within each cell enhance the properties of adaptive modules. An adaptive passenger seat and an aircrafts leading, trailing edge is used to demonstrate the potential of a modular approach. PMID:25289521

  10. Adaptive piezoelectric shell structures: theory and experiments

    NASA Astrophysics Data System (ADS)

    Tzou, H. S.; Zhong, J. P.

    1993-07-01

    Active "smart" space and mechanical structures with adaptive dynamic characteristics have long been interested in a variety of high-performance systems, e.g. flexible space structures, flexible robots, "smart" machines etc. In this paper, an active adaptive structure made of piezoelectric materials is proposed and evaluated. Electromechanical equations of motion and generalised boundary conditions of a generic piezoelectric shell subjected to mechanical and electrical excitations are derived using Hamilton's principle and the linear piezoelectric theory. The structural adaptivity is achieved by a voltage feedback (open or closed loops) utilising the converse piezoelectric effect. Applications of the theory is demonstrated in a bimorph beam case and a cylindrical shell case. Frequency manipulation of the bimorph beam is studied theoretically and experimentally. Damping control of the cylindrical shell via in-plane membrane forces is also investigated.

  11. Nonlinear and distributed parameter models of the mini-mast truss

    NASA Technical Reports Server (NTRS)

    Taylor, Lawrence W., Jr.

    1989-01-01

    Large spacecraft such as Space Station Freedom employ large trusses in their construction. The structural dynamics of such trusses often exhibit nonlinear behavior and little damping which can impact significantly the performance of control systems. The Mini-MAST truss was constructed to research such structural dynamics and control systems. The Mini-MAST truss is an object of study for the guest investigator program as part of NASA's controls-structures interaction program. The Mini-MAST truss is deployable and about 65 ft long. Although the bending characteristics of the Mini-MAST truss are essentially linear, the angular deflection under torsional loading has exhibited significant hysteresis and nonlinear stiffness. It is the purpose to develop nonlinear and distributed parameter models of the truss and to compare the model dynamics with actual measurements. Distributed parameter models have the advantage of requiring fewer model parameters. A tangent function is used to describe the nonlinear stiffness in torsion, partly because of the convenience of its easily expressed inverse. Hysteretic slip elements are introduced and extended to a continuum to account for the observed hysteresis in torsion. The contribution of slipping to the structural damping is analyzed and found to be strongly dependent on the applied loads. Because of the many factors which affect the damping and stiffness in a truss, it is risky to assume linearity.

  12. Modal identification of a deployable space truss

    NASA Technical Reports Server (NTRS)

    Schenk, Axel; Pappa, Richard S.

    1990-01-01

    Work performed under a collaborative research effort between NASA and the German Aerospace Research Establishment (DLR) is summarized. The objective is to develop and demonstrate advanced technology for system identification of future large space structures. Recent experiences using the eigensystem realization algorithm (ERA) for modal identification of Mini-Mast are reported. Mini-Mast is a 20-meter-long deployable space truss used for structural dynamics and active-vibration control research at the NASA Langley Research Center. Due to nonlinearities and numerous local modes, modal identification of Mini-Mast proved to be surprisingly difficult. Methods available with ERA for obtaining detailed, high-confidence results are illustrated.

  13. Offset truss hex solar concentrator

    NASA Technical Reports Server (NTRS)

    White, John E. (Inventor); Sturgis, James D. (Inventor); Erikson, Raymond J. (Inventor); Waligroski, Gregg A. (Inventor); Scott, Michael A. (Inventor)

    1991-01-01

    A solar energy concentrator system comprises an offset reflector structure made up of a plurality of solar energy reflector panel sections interconnected with one another to form a piecewise approximation of a portion of a (parabolic) surface of revolution rotated about a prescribed focal axis. Each panel section is comprised of a plurality of reflector facets whose reflective surfaces effectively focus reflected light to preselected surface portions of the interior sidewall of a cylindrically shaped solar energy receiver. The longitudinal axis of the receiver is tilted at an acute angle with respect to the optical axis such that the distribution of focussed solar energy over the interior surface of the solar engine is optimized for dynamic solar energy conversion. Each reflector panel section comprises a flat, hexagonally shaped truss support framework and a plurality of beam members interconnecting diametrically opposed corners of the hexagonal framework recessed within which a plurality of (spherically) contoured reflector facets is disposed. The depth of the framework and the beam members is greater than the thickness of a reflector facet such that a reflector facet may be tilted (for controlling the effective focus of its reflected light through the receiver aperture) without protruding from the panel section.

  14. A Super Guppy aircraft delivers the S0 truss to KSC.

    NASA Technical Reports Server (NTRS)

    1999-01-01

    The 'Super Guppy' transport aircraft approaches the runway at the KSC's Shuttle Landing Facility. On board is the S0 (S Zero) truss segment, from Boeing in Huntington Beach, Calif. The truss segment, which will become the backbone of the orbiting International Space Station (ISS), is a 44- by 15-foot structure weighing 30,800 pounds when fully outfitted and ready for launch. It will be at the center of the 10-truss, girderlike structure that will ultimately extend the length of a football field on the ISS. Eventually the S0 truss will be attached to the U.S. Lab, 'Destiny,' scheduled to be added to the ISS in April 2000. Later, other trusses will be attached to the S0 truss on-orbit. During processing at KSC, the S0 truss will have installed the Canadian Mobile Transporter, power distribution system modules, a heat pipe radiator for cooling, computers, and a pair of rate gyroscopes. Four Global Positioning System antennas are already installed. The S0 truss is scheduled to be launched in the first quarter of 2001 on mission STS-108.

  15. Installation of the S1 Truss to the International Space Station

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Astronauts Piers J. Sellers (left ) and David A. Wolf work on the newly installed Starboard One (S1) truss to the International Space Station (ISS) during the STS-112 mission. The primary payloads of this mission, ISS Assembly Mission 9A, were the Integrated Truss Assembly S1 (S One), the starboard side thermal radiator truss, and the Crew Equipment Translation Aid (CETA) cart to the ISS. The S1 truss provides structural support for the orbiting research facility's radiator panels, which use ammonia to cool the Station's complex power system. The S1 truss was attached to the S0 (S Zero) truss, which was launched on April 8, 2002 aboard the STS-110, and flows 637 pounds of anhydrous ammonia through three heat-rejection radiators. The truss is 45-feet long, 15-feet wide, 10-feet tall, and weighs approximately 32,000 pounds. The CETA cart was attached to the Mobil Transporter and will be used by assembly crews on later missions. Manufactured by the Boeing Company in Huntington Beach, California, the truss primary structure was transferred to the Marshall Space Flight Center in February 1999 for hardware installations and manufacturing acceptance testing. The launch of the STS-112 mission occurred on October 7, 2002, and its 11-day mission ended on October 18, 2002.

  16. Nonlinear damage identification of breathing cracks in Truss system

    NASA Astrophysics Data System (ADS)

    Zhao, Jie; DeSmidt, Hans

    2014-03-01

    The breathing cracks in truss system are detected by Frequency Response Function (FRF) based damage identification method. This method utilizes damage-induced changes of frequency response functions to estimate the severity and location of structural damage. This approach enables the possibility of arbitrary interrogation frequency and multiple inputs/outputs which greatly enrich the dataset for damage identification. The dynamical model of truss system is built using the finite element method and the crack model is based on fracture mechanics. Since the crack is driven by tensional and compressive forces of truss member, only one damage parameter is needed to represent the stiffness reduction of each truss member. Assuming that the crack constantly breathes with the exciting frequency, the linear damage detection algorithm is developed in frequency/time domain using Least Square and Newton Raphson methods. Then, the dynamic response of the truss system with breathing cracks is simulated in the time domain and meanwhile the crack breathing status for each member is determined by the feedback from real-time displacements of member's nodes. Harmonic Fourier Coefficients (HFCs) of dynamical response are computed by processing the data through convolution and moving average filters. Finally, the results show the effectiveness of linear damage detection algorithm in identifying the nonlinear breathing cracks using different combinations of HFCs and sensors.

  17. Hinge specification for a square-faceted tetrahedral truss

    NASA Technical Reports Server (NTRS)

    Adams, L. R.

    1984-01-01

    A square-faceted tetrahedral truss is geometrically analyzed. Expressions are developed for single degree of freedom hinges which allow packaging of the structure into a configuration in which all members are parallel and closely packed in a square pattern. Deployment is sequential, thus providing control over the structure during deployment.

  18. End-effector - joint conjugates for robotic assembly of large truss structures in space: A second generation

    NASA Technical Reports Server (NTRS)

    Brewer, W. V.

    1988-01-01

    Current designs, a first generation intended for robotic assembly, have given priority to the ease and certainty of the assembly process under less than ideal conditions with a minimum of sensory feedback. As a consequence they are either heavy or expensive and all exhibit a relatively low packaging density. Low packaging density is caused by extensive scars applied to the node, increasing its envelope diameter by as much as 150 percent. Strut envelopes are violated to a lessor extent with diameters increased by 25 percent or more. This smaller percentage is still a significant problem owing to a much higher fraction of the packaged volume represented by struts. As structures in space become larger, packaging density becomes an important consideration. The objective is to develop end-effector-joint conjugates that do not violate the envelopes of a 2.5 inch diameter node or a 1.0 inch diameter strut.

  19. Adaptive structures: some materials and structural issues

    NASA Astrophysics Data System (ADS)

    Roberts, Donald; Lloyd, Peter A.; Hopgood, P.; Mahon, Steve W.; Bowles, A. R.

    2000-08-01

    The concept of using embedded or surface-bonded solid-state actuators to effect shape change in carbon fibre composite laminates continues to have technical merit and appeal. Conventional laminate design methods tend to lead to stiff structures, whilst it is easiest to impose a change of shape on a compliant structure. This presents a possible conflict of design and suggests that the useful performance of solid- state actuators will always be limited by the stiffness of the host laminate. One possible solution is to increase the in-plane work capacity of the actuators either by using improved materials such as phase change perovskites like PLZT or improved eletroding techniques such as inter-digitated electrodes (IDEs). In this study, the performance of several different actuator/laminate systems have been modelled to determine a baseline capability in pure bending. Four cases have been considered for different panel thicknesses and lay-up sequences. The materials performance and IDE design issues have also been addressed. Modelling indicates that even with conventional actuator materials, structural displacements can be produced which could provide useful shape change in applications such as missile roll control.

  20. Optimization of NTP System Truss to Reduce Radiation Shield Mass

    NASA Technical Reports Server (NTRS)

    Scharber, Luke L.; Kharofa, Adam; Caffrey, Jarvis A.

    2016-01-01

    The benefits of nuclear thermal propulsion are numerous and relevant to the current NASA mission goals involving but not limited to the crewed missions to mars and the moon. They do however also present new and unique challenges to the design and logistics of launching/operating spacecraft. One of these challenges, relevant to this discussion, is the significant mass of the shielding which is required to ensure an acceptable radiation environment for the spacecraft and crew. Efforts to reduce shielding mass are difficult to accomplish from material and geometric design points of the shield itself, however by increasing the distance between the nuclear engines and the main body of the spacecraft the required mass of the shielding is lessened considerably. The mass can be reduced significantly per unit length, though any additional mass added by the structure to create this distance serves to offset those savings, thus the design of a lightweight structure is ideal. The challenges of designing the truss are bounded by several limiting factors including; the loading conditions, the capabilities of the launch vehicle, and achieving the ideal truss length when factoring for the overall mass reduced. Determining the overall set of mass values for a truss of varying length is difficult since to maintain an optimally designed truss the geometry of the truss or its members must change. Thus the relation between truss mass and length for these loading scenarios is not linear, and instead has relation determined by the truss design. In order to establish a mass versus length trend for various truss designs to compare with the mass saved from the shield versus length, optimization software was used to find optimal geometric properties that still met the design requirements at established lengths. By solving for optimal designs at various lengths, mass trends could be determined. The initial design findings show a clear benefit to extending the engines as far from the main

  1. TEST AND ANALYSIS ON THE PROGRESSIVE COLLAPSE OF STEEL TRUSSES UNDER CYCLIC LOADING

    NASA Astrophysics Data System (ADS)

    Imase, Fumiaki; Usami, Tsutomu; Funayama, Jyunki; Wang, Chun-Lin

    The objective of this study is to examine experimentally and analytically the damage progress of steel truss structures in cyclic loadings. The adequacy of a numerical model developed in the past study for analyzing truss structures under cyclic or dynamic loadings is examined in view of the test results of model truss structures. Seven steel truss specimens whose panel points are rigidly connected through gusset plates by high-tension bolts were tested under constant vertical loads and cyclically increasing horizontal loads. Two truss models equipped with buckling restrained braces as diagonal members were tested. Moreover, elastic-plastic large displacement analysis is executed with appropriate modeling of test truss structures and with initial lateral loads simulating initial imperfections. In many cases, good correlation between test and analysis is observed up to the points where local bolt hole damages appear near the lower panel points of test truss structures. In addition an analytical model that can examine the up-lift effect of a base plate on the hinge-support has been proposed to improve the analytical modeling.

  2. Development of a verification program for deployable truss advanced technology

    NASA Technical Reports Server (NTRS)

    Dyer, Jack E.

    1988-01-01

    Use of large deployable space structures to satisfy the growth demands of space systems is contingent upon reducing the associated risks that pervade many related technical disciplines. The overall objectives of this program was to develop a detailed plan to verify deployable truss advanced technology applicable to future large space structures and to develop a preliminary design of a deployable truss reflector/beam structure for use a a technology demonstration test article. The planning is based on a Shuttle flight experiment program using deployable 5 and 15 meter aperture tetrahedral truss reflections and a 20 m long deployable truss beam structure. The plan addresses validation of analytical methods, the degree to which ground testing adequately simulates flight and in-space testing requirements for large precision antenna designs. Based on an assessment of future NASA and DOD space system requirements, the program was developed to verify four critical technology areas: deployment, shape accuracy and control, pointing and alignment, and articulation and maneuvers. The flight experiment technology verification objectives can be met using two shuttle flights with the total experiment integrated on a single Shuttle Test Experiment Platform (STEP) and a Mission Peculiar Experiment Support Structure (MPESS). First flight of the experiment can be achieved 60 months after go-ahead with a total program duration of 90 months.

  3. The S1 Truss Prior to Installation on the International Space Station

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Being attached to the Canadarm2 on the International Space Station (ISS), the Remote Manipulator System arm built by the Canadian Space Agency, the Integrated Truss Assembly (S1) Truss is suspended over the Space Shuttle Orbiter Atlantis' cargo bay. Astronauts Sandra H. Magnus, STS-112 mission specialist, and Peggy A. Whitson, Expedition Five flight engineer, used the Canadarm2 from inside the Destiny laboratory on the ISS to lift the S1 truss out of the orbiter's cargo bay and move it into position prior to its installation on the ISS. The primary payloads of this mission, ISS Assembly Mission 9A, were the Integrated Truss Assembly S1 (S One), the starboard side thermal radiator truss, and the Crew Equipment Translation Aid (CETA) cart to the ISS. The S1 truss provides structural support for the orbiting research facility's radiator panels, which use ammonia to cool the Station's complex power system. The S1 truss was attached to the S0 (S Zero) truss, which was launched on April 8, 2002 aboard the STS-110, and flows 637 pounds of anhydrous ammonia through three heat-rejection radiators. The truss is 45-feet long, 15-feet wide, 10-feet tall, and weighs approximately 32,000 pounds. The CETA cart was attached to the Mobil Transporter and will be used by assembly crews on later missions. Manufactured by the Boeing Company in Huntington Beach, California, the truss primary structure was transferred to the Marshall Space Flight Center in February 1999 for hardware installations and manufacturing acceptance testing. The launch of the STS-112 mission occurred on October 7, 2002, and its 11-day mission ended on October 18, 2002.

  4. Parallel computations and control of adaptive structures

    NASA Technical Reports Server (NTRS)

    Park, K. C.; Alvin, Kenneth F.; Belvin, W. Keith; Chong, K. P. (Editor); Liu, S. C. (Editor); Li, J. C. (Editor)

    1991-01-01

    The equations of motion for structures with adaptive elements for vibration control are presented for parallel computations to be used as a software package for real-time control of flexible space structures. A brief introduction of the state-of-the-art parallel computational capability is also presented. Time marching strategies are developed for an effective use of massive parallel mapping, partitioning, and the necessary arithmetic operations. An example is offered for the simulation of control-structure interaction on a parallel computer and the impact of the approach presented for applications in other disciplines than aerospace industry is assessed.

  5. Development of Bonded Joint Technology for a Rigidizable-Inflatable Deployable Truss

    NASA Technical Reports Server (NTRS)

    Smeltzer, Stanley S., III

    2006-01-01

    Microwave and Synthetic Aperture Radar antenna systems have been developed as instrument systems using truss structures as their primary support and deployment mechanism for over a decade. NASA Langley Research Center has been investigating fabrication, modular assembly, and deployment methods of lightweight rigidizable/inflatable linear truss structures during that time for large spacecraft systems. The primary goal of the research at Langley Research Center is to advance these existing state-of-the-art joining and deployment concepts to achieve prototype system performance in a relevant space environment. During 2005, the development, fabrication, and testing of a 6.7 meter multi-bay, deployable linear truss was conducted at Langley Research Center to demonstrate functional and precision metrics of a rigidizable/inflatable truss structure. The present paper is intended to summarize aspects of bonded joint technology developed for the 6.7 meter deployable linear truss structure while providing a brief overview of the entire truss fabrication, assembly, and deployment methodology. A description of the basic joint design, surface preparation investigations, and experimental joint testing of component joint test articles will be described. Specifically, the performance of two room temperature adhesives were investigated to obtain qualitative data related to tube folding testing and quantitative data related to tensile shear strength testing. It was determined from the testing that a polyurethane-based adhesive best met the rigidizable/inflatable truss project requirements.

  6. Wave propagation in equivalent continuums representing truss lattice materials

    DOE PAGESBeta

    Messner, Mark C.; Barham, Matthew I.; Kumar, Mukul; Barton, Nathan R.

    2015-07-29

    Stiffness scales linearly with density in stretch-dominated lattice meta-materials offering the possibility of very light yet very stiff structures. Current additive manufacturing techniques can assemble structures consisting of these lattice materials, but the design of such structures will require accurate, efficient simulation techniques. Equivalent continuum models have several advantages over discrete truss models of stretch dominated lattices, including computational efficiency and ease of model construction. However, the development an equivalent model suitable for representing the dynamic response of a periodic truss is complicated by microinertial effects. This paper derives a dynamic equivalent continuum model for periodic truss structures and verifiesmore » it against detailed finite element simulations. The model must incorporate microinertial effects to accurately reproduce long-wavelength characteristics of the response such as anisotropic elastic soundspeeds. The formulation presented here also improves upon previous work by preserving equilibrium at truss joints for affine lattice deformation and by improving numerical stability by eliminating vertices in the effective yield surface.« less

  7. CLOSEUP VIEW OF BOTTOM OF MAIN BRIDGE CANTILEVER THROUGH TRUSS ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    CLOSE-UP VIEW OF BOTTOM OF MAIN BRIDGE CANTILEVER THROUGH TRUSS SPAN SHOWING RAILROAD PORTION OF FLOOR BEAMS AND OTHER STRUCTURAL COMPONENTS AND LOOKING NORTHWEST. - Huey P. Long Bridge, Spanning Mississippi River approximately midway between nine & twelve mile points upstream from & west of New Orleans, Jefferson, Jefferson Parish, LA

  8. 31. Interior of fabrication buildingnote pipe truss and timber framing. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    31. Interior of fabrication building-note pipe truss and timber framing. Railway to move vessels in and out of structure. Flying bridge roof of barbour-built vessel Stardust (#1) to right. - Barbour Boat Works, Tryon Palace Drive, New Bern, Craven County, NC

  9. STS-110 S0 Truss Removed From Cargo Bay

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Backdropped against the blackness of space and the Earth's horizon, the S0 (S-zero) truss is removed from Atlantis' cargo bay and onto the Destiny laboratory of the International Space Station (ISS) by Astronauts Ellen Ochoa, STS-110 mission specialist, and Daniel W. Bursch, Expedition Four flight engineer, using the ISS' Canadarm2. Space Shuttle Orbiter Atlantis, STS-110 mission, prepared the International Space Station (ISS) for future spacewalks by installing and outfitting the 43-foot-long S0 truss and preparing the first railroad in space, the Mobile Transporter. The 27,000-pound S0 truss was the first of 9 segments that will make up the Station's external framework that will eventually stretch 356 feet (109 meters), or approximately the length of a football field. This central truss segment also includes a flatcar called the Mobile Transporter and rails that will become the first 'space railroad,' which will allow the Station's robotic arm to travel up and down the finished truss for future assembly and maintenance. The completed truss structure will hold solar arrays and radiators to provide power and cooling for additional international research laboratories from Japan and Europe that will be attached to the Station. Milestones of the STS-110 mission included the first use of the Station's robotic arm to maneuver spacewalkers around the Station and it was the first time all of a Shuttle crew's spacewalks were based out of the Station's Quest Airlock. It was also the first Shuttle to use three Block II Main Engines. The Space Shuttle Orbiter Atlantis, STS-110 mission, was launched April 8, 2002 and returned to Earth April 19, 2002.

  10. Expandable panel and truss system/antenna/solar panel

    SciTech Connect

    Slysh, P.

    1983-04-12

    Disclosed is an expandable panel and truss structure capable of being stowed in a storage container (canister) for transportation into space and deployed to form structures such as antennas, solar panels or similar space or terrestial structures. The antenna formed comprises the panels stored as hinged pairs (sets) folded in accordian-like fashion together with the expandable trusses and other devices necessary for antenna space operation, such as attitude control and antenna feed. The panel sets are deployed from the canister to form a toroidal ring, circular in cross-section when deployed, for supporting the antenna lens and to form a feed support boom utilizing the canister as part of the antenna structure. The canister is connected to the ring and support boom in the deployed state by the expandable trusses. A fully automatic system is included for deploying the antenna and for holding the antenna structure in its deployed state. By adding a second (back) boom and reflector screen, a paraboloidal antenna is formed. In a second embodiment, utilizing the same storage and deployment principle but with panel sets which are triangular in cross-section, when deployed, either an offset (asymmetrical) paraboloidal or a feed horn type antenna structure is formed. In another embodiment of the invention, utilizing the same principle and with panel sets which are triangular in crosssection, when deployed, a solar panel array is formed. Also disclosed is a foldable truss geostationary platform and package for transfer into a geostationary orbit. Finally, an alternate mechanism is disclosed in the form of a pantograph for deploying panel sets to form a truss.

  11. STS-110 crew in front of S0 truss in O&C Building

    NASA Technical Reports Server (NTRS)

    2002-01-01

    KENNEDY SPACE CENTER, FLA. -- The STS-110 crew poses under the Integrated Truss Structure S0, ready for transport to the launch pad. Standing left to right are Mission Specialist Jerry Ross, Pilot Stephen Frick, Mission Specialist Lee Morin, Commander Michael Bloomfield, and Mission Specialists Rex Walheim, Ellen Ochoa and Steven Smith. Scheduled for launch April 4, the 11-day STS-110 mission will feature Space Shuttle Atlantis docking with the International Space Station (ISS) and delivering the S0 truss, the centerpiece-segment of the primary truss structure that will eventually extend over 300 feet.

  12. STS-110 payload S0 Truss is lifted into payload changeout room

    NASA Technical Reports Server (NTRS)

    2002-01-01

    KENNEDY SPACE CENTER, FLA. -- On the launch pad, the payload canister with the S0 Integrated Truss Structure moves up the Rotating Service Structure to the payload changeout room for transfer to Space Shuttle Atlantis's payload bay. Part of the payload on mission STS-110, the S0 truss will become the backbone of the orbiting International Space Station (ISS). The S0 truss will be attached to the U.S. Lab, 'Destiny,' on the 11-day mission. Launch is scheduled for April 4.

  13. STS-110 payload S0 Truss is lifted into payload changeout room

    NASA Technical Reports Server (NTRS)

    2002-01-01

    KENNEDY SPACE CENTER, FLA. -- On the launch pad, the payload canister with the S0 Integrated Truss Structure is lifted up the Rotating Service Structure to the payload changeout room for transfer to Space Shuttle Atlantis's payload bay. Part of the payload on mission STS-110, the S0 truss will become the backbone of the orbiting International Space Station (ISS). The S0 truss will be attached to the U.S. Lab, 'Destiny,' on the 11-day mission. Launch is scheduled for April 4.

  14. Adaptive structures - Challenges, issues, and opportunities

    NASA Technical Reports Server (NTRS)

    Das, Alok; Rao, S. V.; Wada, Ben K.; Obal, Michael

    1991-01-01

    Because of the precise pointing/shape control needs of future space systems coupled with a 10-20-year life requirement and very stringent limitations on system weight, a new approach to their control system design was developed. This approach, adaptive structures, exploits recent breakthroughs in advanced composite materials, sensors and actuators, and intelligent control concepts to provide an integrated structure/controller. Ground experiments, the focus of which to demonstrate and evaluate the emerging control hardware and methodologies on realistic three-dimensional testbeds, are also discussed.

  15. Advances in adaptive structures at Jet Propulsion Laboratory

    NASA Technical Reports Server (NTRS)

    Wada, Ben K.; Garba, John A.

    1993-01-01

    Future proposed NASA missions with the need for large deployable or erectable precision structures will require solutions to many technical problems. The Jet Propulsion Laboratory (JPL) is developing new technologies in Adaptive Structures to meet these challenges. The technology requirements, approaches to meet the requirements using Adaptive Structures, and the recent JPL research results in Adaptive Structures are described.

  16. Adaptive vibration damping of fin structures

    NASA Astrophysics Data System (ADS)

    Stuwing, Michael; Sachau, Delf; Breitbach, Elmar J.

    1999-07-01

    Modern military aircraft are characterized by employment of optimized structural components. New demands on exploitation of lightweight construction technology will arise because even greater flexibility with increased maneuverability is desired. The structural integration of multifunctional, often called 'smart' elements, properly activated to e.g. reduce structural loading, offers great potential to necessary advances in military aircraft design. One major problem of modern military aircraft is the buffet loading on the fin structures. Flying the aircraft at high angles of attack allows vortices, evolving from the leading edge of the wing, to hit the fin and excite structural vibrations. This leads to structural attrition as well as a reduced aircraft maneuverability. With the aim to reduce these fin vibrations, an adaptive structure has been developed which is presented in this paper. A concept is discussed with which the vibrational loads are reduced by introduction of counteracting forces using an 'active interface'. This interface concept is characterized by the integration of active, piezoelectric elements directly into the bending support of the fin structure. To validate the stability of the interface FE calculations and extensive measurements on piezoceramic stack actuators have been performed. The manufactured interface was integrate in an existing test structure and realistically loaded. The result will be given in this presentation.

  17. A Super Guppy aircraft delivers the S0 truss to KSC.

    NASA Technical Reports Server (NTRS)

    1999-01-01

    After landing at KSC's Shuttle Landing Facility, the 'Super Guppy' transport aircraft opens to reveal its cargo, a S0 (S Zero) truss segment, from Boeing in Huntington Beach, Calif. The truss segment, which will become the backbone of the orbiting International Space Station (ISS), is a 44- by 15-foot structure weighing 30,800 pounds when fully outfitted and ready for launch. It will be at the center of the ISS 10-truss, girderlike structure that will ultimately extend the length of a football field. Eventually the S0 truss will be attached to the U.S. Lab, 'Destiny,' which is scheduled to be added to the ISS in April 2000. Later, other trusses will be attached to the S0 on-orbit. During processing at KSC, the S0 truss will have installed the Canadian Mobile Transporter, power distribution system modules, a heat pipe radiator for cooling, computers, and a pair of rate gyroscopes. Four Global Positioning System antennas are already installed. The S0 truss is scheduled to be launched in the first quarter of 2001 on mission STS-108.

  18. A Super Guppy aircraft delivers the S0 truss to KSC.

    NASA Technical Reports Server (NTRS)

    1999-01-01

    At KSC's Shuttle Landing Facility, workers watch as a S0 (S Zero) truss segment built for the International Space Station (ISS) is moved out of the 'Super Guppy' aircraft that brought it to KSC from Boeing in Huntington Beach, Calif. At right a cameraman records the exercise. The truss segment, which will become the backbone of the orbiting ISS, is a 44- by 15-foot structure weighing 30,800 pounds when fully outfitted and ready for launch. It will be at the center of the ISS 10-truss, girderlike structure that will ultimately extend the length of a football field. Eventually the S0 truss will be attached to the U.S. Lab, 'Destiny,' which is scheduled to be added to the ISS in April 2000. Later, other trusses will be attached to the S0 on-orbit. During processing at KSC, the Canadian Mobile Transporter will be installed on the S0 truss, followed by power distribution system modules, a heat pipe radiator for cooling, computers, and a pair of rate gyroscopes. Four Global Positioning System antennas are already installed. The S0 truss is scheduled to be launched in the first quarter of 2001 on mission STS-108.

  19. A Super Guppy aircraft delivers the S0 truss to KSC.

    NASA Technical Reports Server (NTRS)

    1999-01-01

    At KSC's Shuttle Landing Facility, the 'Super Guppy' transport aircraft touches down on the runway. On board the aircraft is the S0 (S Zero) truss segment, from Boeing in Huntington Beach, Calif. The truss segment, which will become the backbone of the orbiting International Space Station (ISS), is a 44- by 15-foot structure weighing 30,800 pounds when fully outfitted and ready for launch. It will be at the center of the ISS 10-truss, girderlike structure that will ultimately extend the length of a football field. Eventually the S0 truss will be attached to the U.S. Lab, 'Destiny,' which is scheduled to be added to the ISS in April 2000. Later, other trusses will be attached to the S0 on- orbit. During processing at KSC, the S0 truss will have installed the Canadian Mobile Transporter, power distribution system modules, a heat pipe radiator for cooling, computers, and a pair of rate gyroscopes. Four Global Positioning System antennas are already installed. The S0 truss is scheduled to be launched in the first quarter of 2001 on mission STS-108.

  20. Structured adaptive grid generation using algebraic methods

    NASA Technical Reports Server (NTRS)

    Yang, Jiann-Cherng; Soni, Bharat K.; Roger, R. P.; Chan, Stephen C.

    1993-01-01

    The accuracy of the numerical algorithm depends not only on the formal order of approximation but also on the distribution of grid points in the computational domain. Grid adaptation is a procedure which allows optimal grid redistribution as the solution progresses. It offers the prospect of accurate flow field simulations without the use of an excessively timely, computationally expensive, grid. Grid adaptive schemes are divided into two basic categories: differential and algebraic. The differential method is based on a variational approach where a function which contains a measure of grid smoothness, orthogonality and volume variation is minimized by using a variational principle. This approach provided a solid mathematical basis for the adaptive method, but the Euler-Lagrange equations must be solved in addition to the original governing equations. On the other hand, the algebraic method requires much less computational effort, but the grid may not be smooth. The algebraic techniques are based on devising an algorithm where the grid movement is governed by estimates of the local error in the numerical solution. This is achieved by requiring the points in the large error regions to attract other points and points in the low error region to repel other points. The development of a fast, efficient, and robust algebraic adaptive algorithm for structured flow simulation applications is presented. This development is accomplished in a three step process. The first step is to define an adaptive weighting mesh (distribution mesh) on the basis of the equidistribution law applied to the flow field solution. The second, and probably the most crucial step, is to redistribute grid points in the computational domain according to the aforementioned weighting mesh. The third and the last step is to reevaluate the flow property by an appropriate search/interpolate scheme at the new grid locations. The adaptive weighting mesh provides the information on the desired concentration

  1. 13. 64 foot truss oblique view of the 64 ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    13. 64 foot truss - oblique view of the 64 foot pony truss showing its general configuration. The 80 foot pony trusses are similar. - Weidemeyer Bridge, Spanning Thomes Creek at Rawson Road, Corning, Tehama County, CA

  2. 308. Dennis Hill, Photographer April 1998 VIEW OF DECK TRUSS ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    308. Dennis Hill, Photographer April 1998 VIEW OF DECK TRUSS SPANS WITH THROUGH TRUSS SPANS AND CANTILEVER TRUSS IN BACKGROUND, SOUTH SIDE, FACING WEST. - San Francisco Oakland Bay Bridge, Spanning San Francisco Bay, San Francisco, San Francisco County, CA

  3. 2. VIEW NORTHWEST, GENERAL VIEW SHOWING RAILWAY CANAL TRUSS IN ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. VIEW NORTHWEST, GENERAL VIEW SHOWING RAILWAY CANAL TRUSS IN CENTER, RAILWAY RIVER TRUSS ON LEFT, HIGHWAY TRUSSES IN BACKGROUND - White Rock Bridge, Spanning Pawcatuck River & White Rock Canal, Westerly, Washington County, RI

  4. Active isolation of vibrations with adaptive structures

    NASA Technical Reports Server (NTRS)

    Guigou, C.; Fuller, C. R.; Wagstaff, P. R.

    1991-01-01

    Vibration transmission in structures is controlled by means of a technique which employs distributed arrays of piezoelectric transducers bonded to the supporting structure. Distributed PVDF piezoelectric strips are employed as error sensors, and a two-channel feedforward adaptive LMS algorithm is used for minimizing error signals and thereby controlling the structure. A harmonic force input excites a thick plate, and a receiving plate is configured with three pairs of piezoelectric actuators. Modal analyses are performed to determine the resonant frequencies of the system, and a scanning laser vibrometer is used to study the shape of the response of the receiving plate during excitation with and without the control algorithm. Efficient active isolation of the vibrations is achieved with modal suppression, and good control is noted in the on-resonance cases in which increased numbers of PVDF sensors and piezoelectric actuators are employed.

  5. Spanish adaptation of the structural empowerment scale.

    PubMed

    Jáimez Román, María J; Bretones, Francisco D

    2013-01-01

    The present study's objective is to create a Spanish adaptation of the Conditions of Work Effectiveness Questionnaire II (CWEQ-II) by Laschinger, Finegan, Shamian, and Wilk (2004) in order to measure structural empowerment in an organizational context. To do so, this study was conducted in two distinct phases. In the first, a group of experts carried out a back-translation of the questionnaire and in the second phase, we analyzed the questionnaire's internal structure (through exploratory and confirmatory factor analysis) and external validity. The resulting Spanish version of the questionnaire (CWEQ-S) demonstrated/exhibited good factor structure and good psychometric properties as far as reliability and validity are concerned. PMID:23866208

  6. Performance effects of tie-truss modifications for a 70-meter centerline beam waveguide antenna

    NASA Technical Reports Server (NTRS)

    Cucchissi, J. J.

    1989-01-01

    The elevation-axis tie truss of the 70-m antennas would have to be modified to accommodate a centerline beam waveguide. To accomplish this, the center section of the tie truss has to be altered, causing a change in the tie-truss compliance and affecting structural performance. Even with the center section completely removed, the worst-case rms pathlength error due to gravity load is increased from 0.025 to only 0.030 inches. Using a simple postprocessor technique, the effects of modifying the compliance can be predicted without resorting to multiple and costly re-analyses of large finite-element models on a mainframe computer.

  7. STS-110 payload S0 Truss is moved to payload canister in O&C

    NASA Technical Reports Server (NTRS)

    2002-01-01

    KENNEDY SPACE CENTER, FLA. -- Workers in the Operations and Checkout Building watch as the Integrated Truss Structure S0 is lowered into the payload canister. The S0 truss will soon be on its way to the launch pad for mission STS-110. Part of the payload on Space Shuttle Atlantis, the S0 truss will be attached to the U.S. Lab, 'Destiny,' on the 11-day mission, becoming the backbone of the orbiting International Space Station (ISS). Launch is scheduled for April 4.

  8. Structural features determining thermal adaptation of esterases.

    PubMed

    Kovacic, Filip; Mandrysch, Agathe; Poojari, Chetan; Strodel, Birgit; Jaeger, Karl-Erich

    2016-02-01

    The adaptation of microorganisms to extreme living temperatures requires the evolution of enzymes with a high catalytic efficiency under these conditions. Such extremophilic enzymes represent valuable tools to study the relationship between protein stability, dynamics and function. Nevertheless, the multiple effects of temperature on the structure and function of enzymes are still poorly understood at the molecular level. Our analysis of four homologous esterases isolated from bacteria living at temperatures ranging from 10°C to 70°C suggested an adaptation route for the modulation of protein thermal properties through the optimization of local flexibility at the protein surface. While the biochemical properties of the recombinant esterases are conserved, their thermal properties have evolved to resemble those of the respective bacterial habitats. Molecular dynamics simulations at temperatures around the optimal temperatures for enzyme catalysis revealed temperature-dependent flexibility of four surface-exposed loops. While the flexibility of some loops increased with raising the temperature and decreased with lowering the temperature, as expected for those loops contributing to the protein stability, other loops showed an increment of flexibility upon lowering and raising the temperature. Preserved flexibility in these regions seems to be important for proper enzyme function. The structural differences of these four loops, distant from the active site, are substantially larger than for the overall protein structure, indicating that amino acid exchanges within these loops occurred more frequently thereby allowing the bacteria to tune atomic interactions for different temperature requirements without interfering with the overall enzyme function. PMID:26647400

  9. [Trusses in the current management of hernia].

    PubMed

    Gianom, D; Schubiger, C; Decurtins, M

    2002-11-01

    To assess the frequency and reasons for truss prescription, we surveyed 437 general practitioners collaborating with the surgical department of the Kantonsspital Winterthur and all members of the Swiss Association of Orthotists. 59% of the general practitioners answered. For 85% of them trusses are obsolete. Based on the data of the orthotists, an estimated 1740 trusses are issued in Switzerland annually (250 per million population). In Switzerland approximately 16,000 hernia operations are performed annually. Therefore, 11% of hernia patients are supplied with a truss rather than referred for a consultant surgical opinion. Patients can be divided into groups, one that wears the truss only for a short time in order to delay surgery for medical or occupational reasons and another group, especially elderly patients, that wears the truss permanently. Poor hernia control and pain, hernia incarceration, or dissatisfaction with the uncomfortable truss are reasons for referral to a surgeon. In our personal experience with 14 patients, all judged their situation after the operation better than with the truss. Our study confirms that despite advances in hernia surgery and in the use of regional and local anesthesia trusses are often prescribed. PMID:12430061

  10. Design of a welded joint for robotic, on-orbit assembly of space trusses

    NASA Technical Reports Server (NTRS)

    Rule, W. K.; Thomas, F. P.

    1992-01-01

    A preliminary design for a weldable truss joint for on-orbit assembly of large space structures is described. The joint was designed for ease of assembly, for structural efficiency, and to allow passage of fluid (for active cooling or other purposes) along the member through the joint. The truss members were assumed to consist of graphite/epoxy tubes to which were bonded 2219-T87 aluminum alloy end fittings for welding on-orbit to truss nodes of the same alloy. A modified form of gas tungsten arc welding was assumed to be the welding process. The joint was designed to withstand the thermal and structural loading associated with a 120-ft diameter tetrahedral truss intended as an aerobrake for a mission to Mars.

  11. Design of a welded joint for robotic, on-orbit assembly of space trusses

    NASA Astrophysics Data System (ADS)

    Rule, W. K.; Thomas, F. P.

    1992-10-01

    A preliminary design for a weldable truss joint for on-orbit assembly of large space structures is described. The joint was designed for ease of assembly, for structural efficiency, and to allow passage of fluid (for active cooling or other purposes) along the member through the joint. The truss members were assumed to consist of graphite/epoxy tubes to which were bonded 2219-T87 aluminum alloy end fittings for welding on-orbit to truss nodes of the same alloy. A modified form of gas tungsten arc welding was assumed to be the welding process. The joint was designed to withstand the thermal and structural loading associated with a 120-ft diameter tetrahedral truss intended as an aerobrake for a mission to Mars.

  12. Structured adaptive focusing through scattering media

    NASA Astrophysics Data System (ADS)

    Di Battista, Diego; Ancora, Daniele; Zhang, Haisu; Lemonaki, Krystalia; Avtzi, Stella; Tzortzakis, Stelios; Leonetti, Marco; Zacharakis, Giannis

    2016-03-01

    The combined use of a wavefront modulator and a scattering medium forms an "opaque lens" which forces the light to focus tightly. The adaptive focus has the same shape as the correlation function of the original speckle pattern and it can be generated at defined positions with resolution up to hundreds of nanometers. We have demonstrated that manipulating the speckle pattern spatial components can structure the shape of the focus. Exploiting selectively spatial-frequencies from the speckle components we realized opaque lenses able to produce sub-correlation foci and Bessel beams.

  13. Conceptual design for scaled truss antenna flight experiment

    NASA Technical Reports Server (NTRS)

    Lee, W. H.

    1984-01-01

    The conceptual design for a scaled truss antenna structures experiment program (STASEP) is presented. The hardware analysis of the scaled truss antenna structure (STAS) was performed by interactive design and evaluation of advanced spacecraft (IDEAS) computer aided, interactive, design and analysis program. Four STAS's were designed to be launched by the Shuttle, tested by using the space technology experiments platform (STEP) and space transportation system (STS), and then free flown in short lifetime orbits. Data were gathered on deployment, structural characteristics, geometric accuracies, thermal performance, and drag and lifetime as an orbiting spacecraft. Structural and thermal properties were determined for the STAS, including mass properties, thermal loading, structural natural frequencies, and mode shapes. The necessary analysis, scaling, and ground testing are discussed.

  14. Control of a flexible planar truss using proof mass actuators

    NASA Technical Reports Server (NTRS)

    Minas, Constantinos; Garcia, Ephrahim; Inman, Daniel J.

    1989-01-01

    A flexible structure was modeled and actively controlled by using a single space realizable linear proof mass actuator. The NASA/UVA/UB actuator was attached to a flexible planar truss structure at an optimal location and it was considered as both passive and active device. The placement of the actuator was specified by examining the eigenvalues of the modified model that included the actuator dynamics, and the frequency response functions of the modified system. The electronic stiffness of the actuator was specified, such that the proof mass actuator system was tuned to the fourth structural mode of the truss by using traditional vibration absorber design. The active control law was limited to velocity feedback by integrating of the signals of two accelerometers attached to the structure. The two lower modes of the closed-loop structure were placed further in the LHS of the complex plane. The theoretically predicted passive and active control law was experimentally verified.

  15. Positional control strategies for a modular, long-reach, truss-type manipulator

    NASA Astrophysics Data System (ADS)

    Salerno, Robert James

    1993-01-01

    This dissertation proposes a new type of modular, long-reach, truss type manipulator. Variable Geometry Trusses (VGT's) are used to construct a reconfigurable manipulator system in which all primary members are loaded in pure tension or compression. Each module of the manipulator system is either a static truss link or one of several possible VGT actuators. This results in an extremely stiff and strong manipulator system with minimal overall weight. While many potential applications exist for this technology, the present work was largely motivated by the need for a robotic waste remediation system for underground radioactive waste storage tanks. This new manipulator system provides several advantages when used for this application. The reconfigurable nature of the proposed system allows the manipulator to be adapted on site to unforeseen conditions. Additionally, the kinematic redundancy of the manipulator ensures that solutions can be accomplished even in a highly obstructed workspace. The parallel structure of the truss modules enables the manipulator to be withdrawn in the event of a structural failure. Finally, of particular importance to this task, the open framework of the modules provide a passageway for waste conveyance or additionally, could act as a shielded conduit for control and power cabling. Kinematic analysis algorithms tailored to address the peculiarities of this new manipulator system have also been developed. In this work, the kinematic redundancy of the system is exploited to provide alternative solutions, to avoid numerical difficulties at singularities, or to avoid workspace obstacles. These issues are addressed through a combination of null space optimization procedures and order reduction methods. The null space optimization procedures are accomplished by extracting information from a full singular value decomposition of the jacobian matrix. This method is shown to converge quickly, even for systems with thirty or more degrees of freedom

  16. Adaptive momentum management for large space structures

    NASA Technical Reports Server (NTRS)

    Hahn, E.

    1987-01-01

    Momentum management is discussed for a Large Space Structure (LSS) with the structure selected configuration being the Initial Orbital Configuration (IOC) of the dual keel space station. The external forces considered were gravity gradient and aerodynamic torques. The goal of the momentum management scheme developed is to remove the bias components of the external torques and center the cyclic components of the stored angular momentum. The scheme investigated is adaptive to uncertainties of the inertia tensor and requires only approximate knowledge of principle moments of inertia. Computational requirements are minimal and should present no implementation problem in a flight type computer and the method proposed is shown to be effective in the presence of attitude control bandwidths as low as .01 radian/sec.

  17. Structural dynamic health monitoring of adaptive CFRP structures

    NASA Astrophysics Data System (ADS)

    Kaiser, Stephan; Melcher, Joerg; Breitbach, Elmar J.; Sachau, Delf

    1999-07-01

    The DLR Institute of Structural Mechanics is engaged in the construction and optimization of adaptive structures for aerospace and terrestrial applications. Due to the FFS- Project, one of the recent works of the Institute is the reduction of buffet induced vibration loads at a fin. The construction of modern aircrafts is influenced b the increasing use of fiber composites. They have more specific stiffness and strength properties than metals. On the other hand the layered structure leads to new kinds of damages like delaminations. In the fin interface there are actuators and sensors integrated. Therefore the fin is connected with a controller. For the extension of this adaptive system towards an on-line tool for health monitoring this controller can be used as an identifier of the structure's modal parameters. The most promising procedure is based on MX filters. These filters constitute the filter coefficients from which a fast transformation procedure extracts the modal parameters. The changes of these parameters are related to the location and extent of the damage. So when using the already integrate controller for system identification, one can have a low-cost on-line damage detection for dynamic adaptive structures. First off-line test at CFRP plates have shown the ability to detect delaminations.

  18. P-1 truss moved to work stand in O&C Building

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Inside the Operations and Checkout Building, an overhead crane lifts the top of the canister containing the P-1 truss, a component of the International Space Station. The truss, scheduled to fly in spring of 2002, is part of a total 10-truss, girder-like structure on the Station that will ultimately extend the length of a football field. Astronauts will attach the 14-by- 15 foot structure to the port side of the center truss, S0, during the spring assembly flight. The 33,000-pound P-1 will house the thermal radiator rotating joint (TRRJ) that will rotate the Station's radiators away from the sun to increase their maximum cooling efficiency.

  19. Composite Space Telescope Truss

    NASA Video Gallery

    NASA engineers are recycling an idea for a lightweight, compact space telescope structure from the early 1990s. The 315 struts and 84 nodes were originally designed to enable spacewalking astronaut...

  20. Adaptive dynamics for physiologically structured population models.

    PubMed

    Durinx, Michel; Metz, J A J Hans; Meszéna, Géza

    2008-05-01

    We develop a systematic toolbox for analyzing the adaptive dynamics of multidimensional traits in physiologically structured population models with point equilibria (sensu Dieckmann et al. in Theor. Popul. Biol. 63:309-338, 2003). Firstly, we show how the canonical equation of adaptive dynamics (Dieckmann and Law in J. Math. Biol. 34:579-612, 1996), an approximation for the rate of evolutionary change in characters under directional selection, can be extended so as to apply to general physiologically structured population models with multiple birth states. Secondly, we show that the invasion fitness function (up to and including second order terms, in the distances of the trait vectors to the singularity) for a community of N coexisting types near an evolutionarily singular point has a rational form, which is model-independent in the following sense: the form depends on the strategies of the residents and the invader, and on the second order partial derivatives of the one-resident fitness function at the singular point. This normal form holds for Lotka-Volterra models as well as for physiologically structured population models with multiple birth states, in discrete as well as continuous time and can thus be considered universal for the evolutionary dynamics in the neighbourhood of singular points. Only in the case of one-dimensional trait spaces or when N = 1 can the normal form be reduced to a Taylor polynomial. Lastly we show, in the form of a stylized recipe, how these results can be combined into a systematic approach for the analysis of the (large) class of evolutionary models that satisfy the above restrictions. PMID:17943289

  1. Graphite composite truss welding and cap section forming subsystems. Volume 2: Program results

    NASA Technical Reports Server (NTRS)

    1980-01-01

    The technology required to develop a beam builder which automatically fabricates long, continuous, lightweight, triangular truss members in space from graphite/thermoplastics composite materials is described. Objectives are: (1) continue the development of forming and welding methods for graphite/thermoplastic (GR/TP) composite material; (2) continue GR/TP materials technology development; and (3) fabricate and structurally test a lightweight truss segment.

  2. STS-110 payload S0 Truss is moved to payload canister in O&C

    NASA Technical Reports Server (NTRS)

    2002-01-01

    KENNEDY SPACE CENTER, FLA. -- The Integrated Truss Structure S0 arrives at the payload canister in the Operations and Checkout Building for transfer to the launch pad for mission STS-110. Part of the payload on Space Shuttle Atlantis, the S0 truss will be attached to the U.S. Lab, 'Destiny,' on the 11-day mission, becoming the backbone of the orbiting International Space Station (ISS). Launch is scheduled for April 4.

  3. Strip antenna figure errors due to support truss member length imperfections

    NASA Technical Reports Server (NTRS)

    Greschik, Gyula; Mikular, Martin M.; Helms, Richard G.; Freeland, Robert E.

    2004-01-01

    The dependence of strip antenna steadyy state geometric errors on member length uncertainties in the supporting truss beam is studied with the Monte carlo analysis of a representative truss design. The results, presented in a format streamlined for practical use, can guide the specification for hardware fabrication of required error tolerances (for structural properties as well as member lengths), or they can aid the prediction of antenna performance if component statistics are available.

  4. Deployable Geodesic Truss

    NASA Technical Reports Server (NTRS)

    Mikulas, M. M., Jr.; Rhodes, M. D.; Simonton, J. W.

    1985-01-01

    Efficiently packaged structure deployed or retracted easily. In preliminary two-bay model each bay has sets of battens connected by two longitudinal crossed members that give bay axial and torsional stiffness. Cross-members hinged in center to fold for packaging. Bays deployed and stabilized by actuators connected between center hinges of cross-members.

  5. Adaptive structures for precision controlled large space systems

    NASA Technical Reports Server (NTRS)

    Garba, John A.; Wada, Ben K.; Fanson, James L.

    1991-01-01

    The stringent accuracy and ground test validation requirements of some of the future space missions will require new approaches in structural design. Adaptive structures, structural systems that can vary their geometric congiguration as well as their physical properties, are primary candidates for meeting the functional requirements for such missions. Research performed in the development of such adaptive structural systems is described.

  6. Preliminary design of a large tetrahedral truss/hexagonal heatshield panel aerobrake

    NASA Technical Reports Server (NTRS)

    Dorsey, John T.; Mikulas, Martin M., Jr.

    1989-01-01

    An aerobrake structural concept is introduced which consists of two primary components: (1) a lightweight erectable tetrahedral support truss; and (2) sandwich hexagonal heatshield panels which, when attached to the truss, form a continuous impermeable aerobraking surface. Generic finite element models and a general analysis procedure to design tetrahedral truss/hexagonal heatshield panel aerobrakes is developed, and values of the aerobrake design parameters which minimize mass and packaging volume for a 120-foot-diameter aerobrake are determined. Sensitivity of the aerobrake design to variations in design parameters is also assessed. The results show that a 120-foot-diameter aerobrake is viable using the concept presented (i.e., the aerobrake mass is less than or equal to 15 percent of the payload spacecraft mass). Minimizing the aerobrake mass (by increasing the number of rings in the support truss) however, leads to aerobrakes with the highest part count.

  7. Static task of von Mises planar truss analyzed using the potential energy

    NASA Astrophysics Data System (ADS)

    Kalina, Martin

    2013-10-01

    A Von Mises planar truss subjected to vertical static load at its top joint is studied. The mathematical concept of large displacement elastic analysis of the von Mises truss targeted for computers is described. The model geometry is described using finite mass points. Formulae for the evaluation of displacements of mass points and rotation of segments were derived with the help of geometrical and physical conditions. Formulae for the determination of potential energy of the system are listed. Deformation of the structure is evaluated by seeking the minimal potential energy. The step-by-step increment method combined with Newton-Raphson method is used. The mathematical solution described in the article enables the modelling of Mises truss using a finite amount of segments. The described solution is suitable for load-deflection curve computation of a limit load model. The equilibrium stability problem of von Mises truss is discussed in connection with the random effects of imperfections.

  8. 24 CFR 3280.402 - Test procedures for roof trusses.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... read and recorded to the nearest 1/32-inch. Dead load must be applied to the top and bottom chord, and... truss design evaluated by this procedure. (i) Dead load. Measure and record initial elevation of the truss or trusses in the test position at no load. Apply to the top and bottom chords of the truss...

  9. Truss topology optimization with simultaneous analysis and design

    NASA Technical Reports Server (NTRS)

    Sankaranarayanan, S.; Haftka, Raphael T.; Kapania, Rakesh K.

    1992-01-01

    Strategies for topology optimization of trusses for minimum weight subject to stress and displacement constraints by Simultaneous Analysis and Design (SAND) are considered. The ground structure approach is used. A penalty function formulation of SAND is compared with an augmented Lagrangian formulation. The efficiency of SAND in handling combinations of general constraints is tested. A strategy for obtaining an optimal topology by minimizing the compliance of the truss is compared with a direct weight minimization solution to satisfy stress and displacement constraints. It is shown that for some problems, starting from the ground structure and using SAND is better than starting from a minimum compliance topology design and optimizing only the cross sections for minimum weight under stress and displacement constraints. A member elimination strategy to save CPU time is discussed.

  10. Implementation of local feedback controllers for vibration supression of a truss using active struts

    NASA Astrophysics Data System (ADS)

    McClelland, Robert; Lim, Tae W.; Bosse, Albert; Fisher, Shalom

    1996-05-01

    This paper describes the design and implementation of local feedback controllers for active vibration suppression of a laboratory truss referred to as the Naval Research Laboratory (NRL) space truss. The NRL space truss is a 3.7 meter, 12-bay aluminum laboratory truss used as a testbed to explore smart structures technologies for future Navy spacecraft missions. To conduct real-time control and data acquisition for the implementation of controllers, a digital signal processor based system is used. Two piezoceramic active struts are employed in this experimental study. Each strut is instrumented with a force transducer and a displacement sensor. Modal strain energy computed using a refined finite element model was used to select the optimum locations of the two actuators to ensure controllability of the first two structural modes. Two local feedback controllers were designed and implemented, an integral force feedback and an integral plus double-integral force feedback. The controllers were designed independently for each active strut using classical control design techniques applied to an identified model of the system dynamics. System identification results and controller design procedure are described along with closed loop test results. The test results show up to a factor of 1/110 attenuation of the truss tip motion due to sinusoidal resonant input disturbances and up to 100 times increase in damping of the lower frequency modes of the truss.

  11. 20. 80 foot pony truss an upper chord pin ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    20. 80 foot pony truss - an upper chord pin connection at a vertical post other than at the end post. Common to the five 80 foot trusses and similar to the 64 foot truss, there are two pairs per 80 foot truss and one pair on the 64 foot truss for a total of 22. - Weidemeyer Bridge, Spanning Thomes Creek at Rawson Road, Corning, Tehama County, CA

  12. The Research of Historical Trusses in Northern Regions of Slovakia

    NASA Astrophysics Data System (ADS)

    Korenková, Renáta; Krušinský, Peter

    2014-06-01

    The blanket research of historical trusses in the territory of Slovakia has been running at our department since 2008. This research is done as teamwork in cooperation with experts from the field of conservation, and it is mainly focused on typology, construction, and the current technical and constructional state of investigated trusses. The long-time support of the grant scheme from the Ministry of Culture allows to get a fair amount of different data related to individual buildings and structures, which enables to carry out the in-depth research. In terms of their conservation and maintenance with an effort to extend their lifetime (the oldest known historical trusses in Slovakia are those of the 13th century), it is necessary to look into the microclimate impact of the under-roof space on wooden roof structures as well as to monitor the contemporary constructional and technical condition of a roof structure itself. The suitable microclimate in the under-roof space is influenced by a number of marginal conditions, constructional solutions of roof details, proper space ventilation etc

  13. Trusses in the management of hernia today.

    PubMed

    Cheek, C M; Williams, M H; Farndon, J R

    1995-12-01

    In the UK an estimated 40,000 trusses are issued annually. The rate of 700 per million is higher than that presently found in other countries and may be because of reduced access to surgery. Despite the high use of trusses little has been published on their effectiveness, complication rates and value. This review summarizes current knowledge, and concludes that further studies on the benefits and effectiveness of trusses need to be performed to enable patients to receive appropriate advice and guidance. PMID:8548220

  14. Design, analysis, and testing of the Phase 1 CSI Evolutionary Model erectable truss

    NASA Technical Reports Server (NTRS)

    Gronet, M. J.; Davis, D. A.; Kintis, D. H.; Brillhart, R. D.; Atkins, E. M.

    1992-01-01

    This report addressed the design, analysis, and testing of the erectable truss structure for the Phase 1 CSI Evolutionary Model (CEM) testbed. The Phase 1 CEM testbed is the second testbed to form part of an ongoing program of focused research at NASA/LaRC in the development of Controls-Structures Integration (CSI) technology. The Phase 1 CEM contains the same overall geometry, weight, and sensor locations as the Phase 0 CEM, but is based in an integrated controller and structure design, whereby both structure and controller design variables are sized simultaneously. The Phase 1 CEM design features seven truss sections composed of struts with tailored mass and stiffness properties. A common erectable joint is used and the strut stiffness is tailored by varying the cross-sectional area. To characterize the structure, static tests were conducted on individual struts and 10-bay truss assemblies. Dynamic tests were conducted on 10-bay truss assemblies as well as the fully-assembled CEM truss. The results indicate that the static and dynamic properties of the structure are predictable, well-characterized, and within the performance requirements established during the Phase 1 CEM integrated controller/structure design analysis.

  15. Evolutionary Optimization of a Geometrically Refined Truss

    NASA Technical Reports Server (NTRS)

    Hull, P. V.; Tinker, M. L.; Dozier, G. V.

    2007-01-01

    Structural optimization is a field of research that has experienced noteworthy growth for many years. Researchers in this area have developed optimization tools to successfully design and model structures, typically minimizing mass while maintaining certain deflection and stress constraints. Numerous optimization studies have been performed to minimize mass, deflection, and stress on a benchmark cantilever truss problem. Predominantly traditional optimization theory is applied to this problem. The cross-sectional area of each member is optimized to minimize the aforementioned objectives. This Technical Publication (TP) presents a structural optimization technique that has been previously applied to compliant mechanism design. This technique demonstrates a method that combines topology optimization, geometric refinement, finite element analysis, and two forms of evolutionary computation: genetic algorithms and differential evolution to successfully optimize a benchmark structural optimization problem. A nontraditional solution to the benchmark problem is presented in this TP, specifically a geometrically refined topological solution. The design process begins with an alternate control mesh formulation, multilevel geometric smoothing operation, and an elastostatic structural analysis. The design process is wrapped in an evolutionary computing optimization toolset.

  16. Evolutionary optimization of a Genetically Refined Truss

    NASA Technical Reports Server (NTRS)

    Hull, Patrick V.; Tinker, Michael L.; Dozier, Gerry

    2005-01-01

    Structural optimization is a field of research that has experienced noteworthy growth for many years. Researchers in this area have developed optimization tools to successfully design and model structures, typically minimizing mass while maintaining certain deflection and stress constraints. Numerous optimization studies have been performed to minimize mass, deflection and stress on a benchmark cantilever truss problem. Predominantly traditional optimization theory is applied to this problem. The cross-sectional area of each member is optimized to minimize the aforementioned objectives. This paper will present a structural optimization technique that has been previously applied to compliant mechanism design. This technique demonstrates a method that combines topology optimization, geometric refinement, finite element analysis, and two forms of evolutionary computation: Genetic Algorithms and Differential Evolution to successfully optimize a benchmark structural optimization problem. An non-traditional solution to the benchmark problem is presented in this paper, specifically a geometrically refined topological solution. The design process begins with an alternate control mesh formulation, multilevel geometric smoothing operation, and an elastostatic structural analysis. The design process is wrapped in an evolutionary computing optimization toolset.

  17. Beam and Truss Finite Element Verification for DYNA3D

    SciTech Connect

    Rathbun, H J

    2007-07-16

    The explicit finite element (FE) software program DYNA3D has been developed at Lawrence Livermore National Laboratory (LLNL) to simulate the dynamic behavior of structures, systems, and components. This report focuses on verification of beam and truss element formulations in DYNA3D. An efficient protocol has been developed to verify the accuracy of these structural elements by generating a set of representative problems for which closed-form quasi-static steady-state analytical reference solutions exist. To provide as complete coverage as practically achievable, problem sets are developed for each beam and truss element formulation (and their variants) in all modes of loading and physical orientation. Analyses with loading in the elastic and elastic-plastic regimes are performed. For elastic loading, the FE results are within 1% of the reference solutions for all cases. For beam element bending and torsion loading in the plastic regime, the response is heavily dependent on the numerical integration rule chosen, with higher refinement yielding greater accuracy (agreement to within 1%). Axial loading in the plastic regime produces accurate results (agreement to within 0.01%) for all integration rules and element formulations. Truss elements are also verified to provide accurate results (within 0.01%) for elastic and elastic-plastic loading. A sample problem to verify beam element response in ParaDyn, the parallel version DYNA3D, is also presented.

  18. Solar panel truss mounting systems and methods

    SciTech Connect

    Al-Haddad, Tristan Farris; Cavieres, Andres; Gentry, Russell; Goodman, Joseph; Nolan, Wade; Pitelka, Taylor; Rahimzadeh, Keyan; Brooks, Bradley; Lohr, Joshua; Crooks, Ryan; Porges, Jamie; Rubin, Daniel

    2015-10-20

    An exemplary embodiment of the present invention provides a solar panel truss mounting system comprising a base and a truss assembly coupled to the base. The truss assembly comprises a first panel rail mount, second panel rail mount parallel to the first panel rail mount, base rail mount parallel to the first and second panel rail mounts, and a plurality of support members. A first portion of the plurality of support members extends between the first and second panel rail mounts. A second portion of the plurality of support members extends between the first panel rail mount and the base rail mount. A third portion of the plurality of support members extends between the second panel rail mount and the base rail mount. The system can further comprise a plurality of connectors for coupling a plurality of photovoltaic solar panels to the truss assembly.

  19. Solar panel truss mounting systems and methods

    DOEpatents

    Al-Haddad, Tristan Farris; Cavieres, Andres; Gentry, Russell; Goodman, Joseph; Nolan, Wade; Pitelka, Taylor; Rahimzadeh, Keyan; Brooks, Bradley; Lohr, Joshua; Crooks, Ryan; Porges, Jamie; Rubin, Daniel

    2016-06-28

    An exemplary embodiment of the present invention provides a solar panel truss mounting system comprising a base and a truss assembly coupled to the base. The truss assembly comprises a first panel rail mount, second panel rail mount parallel to the first panel rail mount, base rail mount parallel to the first and second panel rail mounts, and a plurality of support members. A first portion of the plurality of support members extends between the first and second panel rail mounts. A second portion of the plurality of support members extends between the first panel rail mount and the base rail mount. A third portion of the plurality of support members extends between the second panel rail mount and the base rail mount. The system can further comprise a plurality of connectors for coupling a plurality of photovoltaic solar panels to the truss assembly.

  20. Adaptive Control of Flexible Structures Using Residual Mode Filters

    NASA Technical Reports Server (NTRS)

    Balas, Mark J.; Frost, Susan

    2010-01-01

    Flexible structures containing a large number of modes can benefit from adaptive control techniques which are well suited to applications that have unknown modeling parameters and poorly known operating conditions. In this paper, we focus on a direct adaptive control approach that has been extended to handle adaptive rejection of persistent disturbances. We extend our adaptive control theory to accommodate troublesome modal subsystems of a plant that might inhibit the adaptive controller. In some cases the plant does not satisfy the requirements of Almost Strict Positive Realness. Instead, there maybe be a modal subsystem that inhibits this property. This section will present new results for our adaptive control theory. We will modify the adaptive controller with a Residual Mode Filter (RMF) to compensate for the troublesome modal subsystem, or the Q modes. Here we present the theory for adaptive controllers modified by RMFs, with attention to the issue of disturbances propagating through the Q modes. We apply the theoretical results to a flexible structure example to illustrate the behavior with and without the residual mode filter. We have proposed a modified adaptive controller with a residual mode filter. The RMF is used to accommodate troublesome modes in the system that might otherwise inhibit the adaptive controller, in particular the ASPR condition. This new theory accounts for leakage of the disturbance term into the Q modes. A simple three-mode example shows that the RMF can restore stability to an otherwise unstable adaptively controlled system. This is done without modifying the adaptive controller design.

  1. Optimization of space trusses on vector multiprocessor

    SciTech Connect

    Adeli, H.; Hsu, H.L.

    1994-01-01

    Mathematical optimization of space trusses in a vector/parallel processing environment is the subject of this paper. Parallel processing is achieved through microtasking and the use of the CRAY CFT77 compiler directives. Speed-up results are presented for four space-truss examples. It is concluded that the speedup due to microtasking is improved substantially with an increase in the size of the problem.

  2. A crane is lowered toward the S0 truss to transfer it to a workstand in the

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Inside the Operations and Checkout Bldg. (O&C), workers (at left) watch over the maneuvering of the overhead crane toward the S0 truss segment below it. The S0 truss will undergo processing in the O&C during which the Canadian Mobile Transporter, power distribution system modules, a heat pipe radiator for cooling, computers, and a pair of rate gyroscopes will be installed. Four Global Positioning System antennas are already installed. A 44- by 15-foot structure weighing 30,800 pounds when fully outfitted and ready for launch, the truss will be at the center of the ISS 10-truss, girderlike structure that will ultimately extend the length of a football field. Eventually the S0 truss will be attached to the U.S. Lab, 'Destiny,' which is scheduled to be added to the ISS in April 2000. Later, other trusses will be attached to the S0 on-orbit. The S0 truss is scheduled to be launched in the first quarter of 2001 on mission STS-108.

  3. Structurally adaptive space crane concept for assembling space systems on orbit

    NASA Technical Reports Server (NTRS)

    Dorsey, John T.; Sutter, Thomas R.; Wu, K. Chauncey

    1992-01-01

    Many future human space exploration missions will probably require large vehicles that must be assembled on orbit. Thus, a device that can move, position, and assemble large and massive spacecraft components on orbit becomes essential for these missions. A concept is described for such a device: a space crane concept that uses erectable truss hardware to achieve high-stiffness and low-mass booms and uses articulating truss joints that can be assembled on orbit. The hardware has been tested and shown to have linear load-deflection response and to be structurally predictable. The hardware also permits the crane to be reconfigured into different geometries to satisfy future assembly requirements. A number of articulating and rotary joint concepts have been sized and analyzed, and the results are discussed. Two strategies were proposed to suppress motion-induced vibration: placing viscous dampers in selected truss struts and preshaping motion commands. Preliminary analyses indicate that these techniques have the potential to greatly enhance structural damping.

  4. Parallel adaptive mesh refinement for electronic structure calculations

    SciTech Connect

    Kohn, S.; Weare, J.; Ong, E.; Baden, S.

    1996-12-01

    We have applied structured adaptive mesh refinement techniques to the solution of the LDA equations for electronic structure calculations. Local spatial refinement concentrates memory resources and numerical effort where it is most needed, near the atomic centers and in regions of rapidly varying charge density. The structured grid representation enables us to employ efficient iterative solver techniques such as conjugate gradients with multigrid preconditioning. We have parallelized our solver using an object-oriented adaptive mesh refinement framework.

  5. Tests of an alternate mobile transporter and extravehicular activity assembly procedure for the Space Station Freedom truss

    NASA Technical Reports Server (NTRS)

    Heard, Walter L., Jr.; Watson, Judith J.; Lake, Mark S.; Bush, Harold G.; Jensen, J. Kermit; Wallsom, Richard E.; Phelps, James E.

    1992-01-01

    Results are presented from a ground test program of an alternate mobile transporter (MT) concept and extravehicular activity (EVA) assembly procedure for the Space Station Freedom (SSF) truss keel. A three-bay orthogonal tetrahedral truss beam consisting of 44 2-in-diameter struts and 16 nodes was assembled repeatedly in neutral buoyancy by pairs of pressure-suited test subjects working from astronaut positioning devices (APD's) on the MT. The truss bays were cubic with edges 15 ft long. All the truss joint hardware was found to be EVA compatible. The average unit assembly time for a single pair of experienced test subjects was 27.6 sec/strut, which is about half the time derived from other SSF truss assembly tests. A concept for integration of utility trays during truss assembly is introduced and demonstrated in the assembly tests. The concept, which requires minimal EVA handling of the trays, is shown to have little impact on overall assembly time. The results of these tests indicate that by using an MT equipped with APD's, rapid EVA assembly of a space station-size truss structure can be expected.

  6. [Truss-induced macular amyloidosis].

    PubMed

    Abels, C; Karrer, S; Landthaler, M; Szeimies, R M

    2001-10-01

    A 80-year-old male presented with a long time history of a localized red-brown macule with superficial lichenification and slight scaling in the right groin. An earlier skin biopsy revealed the presence of amyloid deposits. The patient therefore had a complete internal checkup including a rectal biopsy for exclusion of systemic amyloidosis. However, the laboratory data did not reveal any specific abnormalities including immunoglobulins and Bence-Jones protein. The rectal biopsy was also nonspecific. After skin examination, a rebiopsy was performed at our department showing acanthosis and spongiosis of the epidermis with parakeratosis. A homogenous eosinophilic deposit was present in the upper dermis and stained positive with thioflavine. At the second visit the patient wore a truss for a right inguinal hernia, perfectly matching the area of the skin lesion. Thus, the diagnosis of a localized macular amyloidosis was confirmed very likely due to permanent local friction. The classification of localized cutaneous amyloidoses should include local trauma as a cause to avoid unnecessary and exhausting internal checkups to exclude systemic involvement. PMID:11715396

  7. 5. DETAIL VIEW OF TWO PANEL POINTS OF TRUSS, SHOWING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    5. DETAIL VIEW OF TWO PANEL POINTS OF TRUSS, SHOWING OVAL, TUBULAR UPPER CHORD MEMBER, VERTICALS, DIAGONALS, AND LOWER CHORD. - White Bowstring Arch Truss Bridge, Spanning Yellow Creek at Cemetery Drive (Riverside Drive), Poland, Mahoning County, OH

  8. 21. DETAIL OF SPRING BLOCK AND BASE OF ROOF TRUSS ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    21. DETAIL OF SPRING BLOCK AND BASE OF ROOF TRUSS ON WEST WALL OF NORTHEAST TRANSEPT. NOTE REINFORCING ADDED TO TRUSS IN DISTANCE. - Cornell University, Sage Chapel, Central Avenue, Ithaca, Tompkins County, NY

  9. 9. 64 foot pony truss south west bearing abutment ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    9. 64 foot pony truss - south west bearing abutment of the first pony, truss, showing the sheet piling and the added 'I' beam support. - Weidemeyer Bridge, Spanning Thomes Creek at Rawson Road, Corning, Tehama County, CA

  10. 12. 80 foot pony truss looking east from the ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    12. 80 foot pony truss - looking east from the upstream side, view of a single pony truss showing its general arrangement on replacement piers, circa 1966. - Weidemeyer Bridge, Spanning Thomes Creek at Rawson Road, Corning, Tehama County, CA

  11. 23. 100 foot through truss looking west from the ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    23. 100 foot through truss - looking west from the downstream side, view of a single through truss showing its general arrangement on extended column piers. - Weidemeyer Bridge, Spanning Thomes Creek at Rawson Road, Corning, Tehama County, CA

  12. 5. DETAIL OF OTHER END OF TRUSS WITH PLATE IDENTIFYING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    5. DETAIL OF OTHER END OF TRUSS WITH PLATE IDENTIFYING 'COMMISSIONERS J. C. ROBINSON, PETER KNITTLE, DAVID H. EDWARDS.' - Town Creek Truss-leg Bedstead Bridge, Spanning Town Creek at County Route 82, Van Wert, Van Wert County, OH

  13. 4. DETAIL OF TRUSS END AND MAKER'S PLATE WHICH STATES ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. DETAIL OF TRUSS END AND MAKER'S PLATE WHICH STATES 'BRACKETT BRIDGE CO., BUILDERS, CINCINNATI, O. 1894.' - Town Creek Truss-leg Bedstead Bridge, Spanning Town Creek at County Route 82, Van Wert, Van Wert County, OH

  14. Detail One Half of Wood Truss, Detail One Quarter Plan ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Detail One Half of Wood Truss, Detail One Quarter Plan of Floor Beams & Bottom Truss Cord, Detail at A Plan, Detail at B Plan - Covered Bridge, Spanning Darby Creek, North Lewisburg, Champaign County, OH

  15. 2. GENERAL VIEW OF BRIDGE SHOWING PARKER THROUGH TRUSS CENTER ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. GENERAL VIEW OF BRIDGE SHOWING PARKER THROUGH TRUSS CENTER SPAN AND DECK TRUSS SPANS AT EITHER SIDE OF CENTER SPAN, LOOKING NORTHWEST - Ouachita River Bridge, Spanning Ouachita River at U.S. Highway 167, Calion, Union County, AR

  16. Community Structure and Vietnamese Refugee Adaptation: The Significance of Context.

    ERIC Educational Resources Information Center

    Starr, Paul D.; Roberts, Alden E.

    1982-01-01

    Describes research investigating the effects of community structure on the adjustment of Vietnamese refugees in America. Emphasizes how congruence between individual characteristics and characteristics of the receiving community determine successful refugee adaptation to a new environment. (MJL)

  17. Ground vibration tests of a high fidelity truss for verification of on orbit damage location techniques

    NASA Technical Reports Server (NTRS)

    Kashangaki, Thomas A. L.

    1992-01-01

    This paper describes a series of modal tests that were performed on a cantilevered truss structure. The goal of the tests was to assemble a large database of high quality modal test data for use in verification of proposed methods for on orbit model verification and damage detection in flexible truss structures. A description of the hardware is provided along with details of the experimental setup and procedures for 16 damage cases. Results from selected cases are presented and discussed. Differences between ground vibration testing and on orbit modal testing are also described.

  18. P-1 truss moved to work stand in O&C Building

    NASA Technical Reports Server (NTRS)

    2000-01-01

    The P-1 truss, a component of the International Space Station, is moved the length of the Operations and Checkout Building to its work stand where it will undergo processing. Scheduled to fly in spring of 2002, the P-1 is part of a total 10-truss, girder-like structure on the Station that will ultimately extend the length of a football field. Astronauts will attach the 14-by-15 foot structure to the port side of the center truss, S0, during the spring assembly flight. The 33,000-pound P-1 will house the thermal radiator rotating joint (TRRJ) that will rotate the Station's radiators away from the sun to increase their maximum cooling efficiency.

  19. P-1 truss moved to work stand in O&C Building

    NASA Technical Reports Server (NTRS)

    2000-01-01

    The P-1 truss, a component of the International Space Station, is lowered into a work stand in the Operations and Checkout Building where it will undergo processing. Scheduled to fly in spring of 2002, the P-1 is part of a total 10-truss, girder-like structure on the Station that will ultimately extend the length of a football field. Astronauts will attach the 14-by-15 foot structure to the port side of the center truss, S0, during the spring assembly flight. The 33,000-pound P-1 will house the thermal radiator rotating joint (TRRJ) that will rotate the Station's radiators away from the sun to increase their maximum cooling efficiency.

  20. P-1 truss moved to work stand in O&C Building

    NASA Technical Reports Server (NTRS)

    2000-01-01

    The P-1 truss (top of photo), a component of the International Space Station, nears its work stand in the Operations and Checkout Building where it will undergo processing. Scheduled to fly in spring of 2002, the P-1 is part of a total 10-truss, girder-like structure on the Station that will ultimately extend the length of a football field. Astronauts will attach the 14-by- 15 foot structure to the port side of the center truss, S0, during the spring assembly flight. The 33,000-pound P-1 will house the thermal radiator rotating joint (TRRJ) that will rotate the Station's radiators away from the sun to increase their maximum cooling efficiency.

  1. P-1 truss moved to work stand in O&C Building

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Inside the Operations and Checkout Building, the P-1 truss, a component of the International Space Station, is lifted out of its canister to move to a work stand where it will undergo processing. Scheduled to fly in spring of 2002, the P-1 is part of a total 10-truss, girder-like structure on the Station that will ultimately extend the length of a football field. Astronauts will attach the 14-by-15 foot structure to the port side of the center truss, S0, during the spring assembly flight. The 33,000- pound P-1 will house the thermal radiator rotating joint (TRRJ) that will rotate the Station's radiators away from the sun to increase their maximum cooling efficiency.

  2. Harmonic finite-element thermoelastic analysis of space frames and trusses

    SciTech Connect

    Givoli, D.; Rand, O. )

    1993-09-01

    A numerical procedure is devised for the thermoelastic analysis of three-dimensional frame- or truss-type space structures exposed to solar radiation. Thin-walled frame or truss members with cross sections of arbitrary shape are considered. Tension-compression, bending, shear, and torsional effects due to the temperature distribution induced by the solar radiation are all taken into account. The procedure proposed involves finite element discretization in the axial direction and a harmonic analysts in the circumferential direction of each member. This procedure is an extension of the one employed previously to obtain the temperature field in trusses. A multibay frame structure serves as a model to demonstrate the performance of the proposed method. The temperature, displacement, and stress fields in the frame are found in various cases. 23 refs.

  3. Closeup view showing portion of continuous bottom chord of truss ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Close-up view showing portion of continuous bottom chord of truss with other web members and posts of the truss connected thereto at a joint by the use of a large steel pin. Note: The timber ties supporting the track (not shown but above) span transversely from truss to truss which are on 16' -0 centers. - Bridgeport Swing Span Bridge, Spanning Tennessee River, Bridgeport, Jackson County, AL

  4. P1 Truss Radiator assembly processing at KSC

    NASA Technical Reports Server (NTRS)

    2002-01-01

    KENNEDY SPACE CENTER, FLA. -- In the Space Station Processing Facility, workers prepare to attach an overhead crane to the radiator assembly that just arrived. The radiator is part of the payload on mission STS-113, which also includes the first port truss segment, P1 Truss, to be attached to the central truss segment, S0 Truss, on the International Space Station. Once delivered, the will remain stowed until flight 12A.1. STS-113 is scheduled to launch Oct. 6, 2002

  5. P1 Truss Radiator assembly processing at KSC

    NASA Technical Reports Server (NTRS)

    2002-01-01

    KENNEDY SPACE CENTER, FLA. -- In the Space Station Processing Facility, workers oversee the lowering of the newly arrived radiator assembly onto a workstand. The radiator is part of the payload on mission STS-113, which also includes the first port truss segment, P1 Truss, to be attached to the central truss segment, S0 Truss, on the International Space Station. Once delivered, the will remain stowed until flight 12A.1. STS-113 is scheduled to launch Oct. 6, 2002

  6. P1 Truss Radiator assembly processing at KSC

    NASA Technical Reports Server (NTRS)

    2002-01-01

    KENNEDY SPACE CENTER, FLA. -- In the Space Station Processing Facility, an overhead crane moves the newly arrived radiator assembly toward a workstand. The radiator is part of the payload on mission STS-113, which also includes the first port truss segment, P1 Truss, to be attached to the central truss segment, S0 Truss, on the International Space Station. Once delivered, the will remain stowed until flight 12A.1. STS-113 is scheduled to launch Oct. 6, 2002

  7. P1 Truss Radiator assembly processing at KSC

    NASA Technical Reports Server (NTRS)

    2002-01-01

    KENNEDY SPACE CENTER, FLA. -- In the Space Station Processing Facility, workers help guide the newly arrived radiator assembly onto a workstand. The radiator is part of the payload on mission STS-113, which also includes the first port truss segment, P1 Truss, to be attached to the central truss segment, S0 Truss, on the International Space Station. Once delivered, the will remain stowed until flight 12A.1. STS-113 is scheduled to launch Oct. 6, 2002

  8. Control of sound radiation with active/adaptive structures

    NASA Technical Reports Server (NTRS)

    Fuller, C. R.; Rogers, C. A.; Robertshaw, H. H.

    1992-01-01

    Recent research is discussed in the area of active structural acoustic control with active/adaptive structures. Progress in the areas of structural acoustics, actuators, sensors, and control approaches is presented. Considerable effort has been given to the interaction of these areas with each other due to the coupled nature of the problem. A discussion is presented on actuators bonded to or embedded in the structure itself. The actuators discussed are piezoceramic actuators and shape memory alloy actuators. The sensors discussed are optical fiber sensors, Nitinol fiber sensors, piezoceramics, and polyvinylidene fluoride sensors. The active control techniques considered are state feedback control techniques and least mean square adaptive algorithms. Results presented show that significant progress has been made towards controlling structurally radiated noise by active/adaptive means applied directly to the structure.

  9. 30. 100 foot through truss detail of an upper, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    30. 100 foot through truss - detail of an upper, inside, corner of a through truss. Shows the upper chord pin connection, end post, lateral lace strut and sway bracing. There are four of these per through truss, for a total of eight. - Weidemeyer Bridge, Spanning Thomes Creek at Rawson Road, Corning, Tehama County, CA

  10. 28. 100 foot through truss a typical lower chord ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    28. 100 foot through truss - a typical lower chord pin connection, located below each vertical lace post on the through trusses. Each truss has four of these for a total of eight. Shown is the floor beam below the pin connection, and the four inch conduit. - Weidemeyer Bridge, Spanning Thomes Creek at Rawson Road, Corning, Tehama County, CA

  11. 31. 100 foot through truss view is the outside ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    31. 100 foot through truss - view is the outside of an upper chord pin connection at the end post of a through truss. Shown also, is the ornamental urn treatment, one placed at each of the upper end post junctions of the truss. Only seven of the original eight remain today. - Weidemeyer Bridge, Spanning Thomes Creek at Rawson Road, Corning, Tehama County, CA

  12. Bridge Types: Suspension Bridge Spans, Section AA; Cantilever Truss Spans, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Bridge Types: Suspension Bridge Spans, Section A-A; Cantilever Truss Spans, Section B-B; Through Truss Spans, Section C-C; Deck Truss Spans, Section D-D - San Francisco Oakland Bay Bridge, Spanning San Francisco Bay, San Francisco, San Francisco County, CA

  13. 13. View of Truss tower and pivot pier locking east. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    13. View of Truss tower and pivot pier locking east. When the draw is open, the two arms of the truss act as cantilevers supported by the truss tower. A counterweight in the shorter of the bridge keeps the span in proper balance. - Center Street Swing Bridge, Southwest of Public Square, Cleveland, Cuyahoga County, OH

  14. 40. GARRET TRUSS DETAIL. The south queen post (called 'king ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    40. GARRET TRUSS DETAIL. The south queen post (called 'king post' in the 1755 account for scantling for the Greater Meeting House) of the third truss from the east end. Note the numerals for assembling the truss members and the plaster marks from the 1755 Monthly Meeting Room. - Twelfth Street Meeting House, 20 South Twelfth Street, Philadelphia, Philadelphia County, PA

  15. 9. GENERAL VIEW OF THE CAST IRON TRUSS SYSTEM IN ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    9. GENERAL VIEW OF THE CAST IRON TRUSS SYSTEM IN THE ATTIC OF UNIT 2, SHOWING THE JUNCTION OF THE TRUSSES ABOVE THE MAIN ENTRY GABLE WITH THE TYPICAL TRUSS SYSTEM FOR THE WING; LOOKING SSW. (Ryan and Ceronie) - Watervliet Arsenal, Building No. 40, Broadway between Dalliba & Watervliet Avenues, Watervliet, Albany County, NY

  16. UNIDENTIFIED CATENARY SUSPENSION BRIDGE WITH TRUSSED OBELISK TOWERS ON STONE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    UNIDENTIFIED CATENARY SUSPENSION BRIDGE WITH TRUSSED OBELISK TOWERS ON STONE PIERS, SHOWING HOWE PIPE TRUSS RAILING AND TRUSSED DECK BEAMS TYPICAL TO BRIDGES BUILT BY FLINN-MOYER COMPANY. 3/4 VIEW FROM BELOW. - Clear Fork of Brazos River Suspension Bridge, Spanning Clear Fork of Brazos River at County Route 179, Albany, Shackelford County, TX

  17. Auxeticity in truss networks and the role of bending versus stretching deformation

    NASA Astrophysics Data System (ADS)

    Desmoulins, Albert; Zelhofer, Alex J.; Kochmann, Dennis M.

    2016-05-01

    Auxetic behavior (i.e., a negative value of Poisson’s ratio) has been reported for a variety of cellular networks including truss structures. Commonly, this implies that the geometric arrangement of truss members within a periodic unit cell is designed to achieve the negative Poisson effect, e.g., in the reentrant honeycomb configuration. Here, we show that elastic periodic truss lattices can be tuned to display auxeticity by controlling the ratio of bending to stretching stiffness. If the nodal stiffness (or the bending stiffness) is low compared to the stretching stiffness of individual truss members, then the lattice is expected to exhibit a positive Poisson’s ratio, showing lateral expansion upon uniaxial compression. In contrast, if the nodal or bending stiffness is high (and buckling is prevented), the lattice may reveal auxetic behavior, contracting laterally under uniaxial compression. This effect is demonstrated in two dimensions for the examples of square and triangular lattices, and it is confirmed both analytically in the limit of small strains as well as numerically for finite elastic deformation. Under large deformation, instability additionally gives rise to auxetic behavior due to truss buckling.

  18. PaR Tensile Truss for Nuclear Decontamination and Decommissioning - 12467

    SciTech Connect

    Doebler, Gary R.

    2012-07-01

    Remote robotics and manipulators are commonly used in nuclear decontamination and decommissioning (D and D) processes. D and D robots are often deployed using rigid telescoping masts in order to apply and counteract side loads. However, for very long vertical reaches (15 meters or longer) and high lift capacities, a telescopic is usually not practical due to the large cross section and weight required to make the mast stiff and resist seismic forces. For those long vertical travel applications, PaR Systems has recently developed the Tensile Truss, a rigid, hoist-driven 'structure' that employs six independent wire rope hoists to achieve long vertical reaches. Like a mast, the Tensile Truss is typically attached to a bridge-mounted trolley and is used as a platform for robotic manipulators and other remotely operated tools. For suspended, rigid deployment of D and D tools with very long vertical reaches, the Tensile Truss can be a better alternative than a telescoping mast. Masts have length limitations that can make them impractical or unworkable as lengths increase. The Tensile Truss also has the added benefits of increased safety, ease of decontamination, superior stiffness and ability to withstand excessive side loading. A Tensile Truss system is currently being considered for D and D operations and spent fuel recovery at the Fukushima Daiichi Nuclear Power Plant in Japan. This system will deploy interchangeable tools such as underwater hydraulic manipulators, hydraulic shears and crushers, grippers and fuel grapples. (authors)

  19. Structural Probability Concepts Adapted to Electrical Engineering

    NASA Technical Reports Server (NTRS)

    Steinberg, Eric P.; Chamis, Christos C.

    1994-01-01

    Through the use of equivalent variable analogies, the authors demonstrate how an electrical subsystem can be modeled by an equivalent structural subsystem. This allows the electrical subsystem to be probabilistically analyzed by using available structural reliability computer codes such as NESSUS. With the ability to analyze the electrical subsystem probabilistically, we can evaluate the reliability of systems that include both structural and electrical subsystems. Common examples of such systems are a structural subsystem integrated with a health-monitoring subsystem, and smart structures. Since these systems have electrical subsystems that directly affect the operation of the overall system, probabilistically analyzing them could lead to improved reliability and reduced costs. The direct effect of the electrical subsystem on the structural subsystem is of secondary order and is not considered in the scope of this work.

  20. Gradient-based adaptation of continuous dynamic model structures

    NASA Astrophysics Data System (ADS)

    La Cava, William G.; Danai, Kourosh

    2016-01-01

    A gradient-based method of symbolic adaptation is introduced for a class of continuous dynamic models. The proposed model structure adaptation method starts with the first-principles model of the system and adapts its structure after adjusting its individual components in symbolic form. A key contribution of this work is its introduction of the model's parameter sensitivity as the measure of symbolic changes to the model. This measure, which is essential to defining the structural sensitivity of the model, not only accommodates algebraic evaluation of candidate models in lieu of more computationally expensive simulation-based evaluation, but also makes possible the implementation of gradient-based optimisation in symbolic adaptation. The proposed method is applied to models of several virtual and real-world systems that demonstrate its potential utility.

  1. 25. 'HANGAR SHEDS TRUSSES DETAILS; ARCHITECTURAL PLANS ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    25. 'HANGAR SHEDS - TRUSSES - DETAILS; ARCHITECTURAL PLANS - PLANT AREA; MODIFICATION CENTER NO. 1, DAGGETT, CALIFORNIA.' Sections and details of trusses, ironwork, and joints, as modified to show ridge joint detail. As built. This blueline also shows the fire suppression system, added in orange pencil for 'Project 13: Bldgs. T-30, T-50, T-70, T-90' at a later, unspecified date. Contract no. W509 Eng. 2743; File no. 555/84, revision B, dated August 24, 1942. No sheet number. - Barstow-Daggett Airport, Hangar Shed No. 4, 39500 National Trails Highway, Daggett, San Bernardino County, CA

  2. Devices prevent ice damage to trusses of semi

    SciTech Connect

    Marthinsen, A.

    1985-04-01

    Much exploration drilling is done in subarctic waters around the world, and this will be important in the future. Special demands will be made on the drilling structures to enable them to withstand collisions with drifting ice. A Newfoundland Certificate of Fitness, for example, says a vessel must be able to tolerate collision with the largest iceberg that can be undetectable by radar, with out the danger of platform collapse. The iceberg in this case is defined as having a weight of 5000 tons and a drifting velocity of 2 meters/second. Devices to prevent ice damage to the trusses of semisubmersibles are discussed.

  3. Distributed parameter estimation for NASA Mini-Mast truss through displacement measurements

    NASA Technical Reports Server (NTRS)

    Huang, Jen-Kuang; Shen, Ji-Yao; Taylor, Lawrence W., Jr.

    1991-01-01

    Most methods of system identification of large flexible structures by far are based on the lumped parameter approach. Because of the considerable computational burden due to the large number of unknown parameters, distributed parameter approach, which greatly decreases the number of unknowns, has being investigated. In this paper a distributed parameter model for the estimation of modal characteristics of NASA Mini-Mast truss has been formulated. Both Bernoulli-Euler beam and Timoshenko beam equations are used to characterize the lateral bending vibrations of the truss. The measurement of the lateral displacement at the tip of the truss is provided to the maximum likelihood estimator. Closed-form solutions of the partial differential equations and closed-form expressions of the sensitivity functions are derived so that the estimation algorithm is highly efficient. The resulting estimates from test data by using Timoshenko beam model are found to be comparable to those derived from finite element analysis.

  4. STS-113 P1 Truss payload in the SSPF

    NASA Technical Reports Server (NTRS)

    2002-01-01

    KENNEDY SPACE CENTER, FLA. -- Inside the Space Station Processing Facility, technicians use an overhead crane to lower the P1 Truss Segment into the payload canister. The P1 truss is the primary payload for Mission STS-113. It is the first port truss segment which will be attached to the Station'''s central truss segment, S0. Once delivered, the P1 truss will remain stowed until flight 12A.1. The mission will also deliver the Expedition 6 crew to the Station and return Expedition 5 to Earth. Space Shuttle Endeavour is scheduled to launch no earlier than Nov. 10 on the 11-day mission.

  5. STS-113 P1 Truss payload in the SSPF

    NASA Technical Reports Server (NTRS)

    2002-01-01

    KENNEDY SPACE CENTER, FLA. -- Inside the Space Station Processing Facility, the P1 Truss Segment is lowered into the payload canister. The P1 truss is the primary payload for Mission STS-113. It is the first port truss segment which will be attached to the Station'''s central truss segment, S0. Once delivered, the P1 truss will remain stowed until flight 12A.1. The mission will also deliver the Expedition 6 crew to the Station and return Expedition 5 to Earth. Space Shuttle Endeavour is scheduled to launch no earlier than Nov. 10 on the 11-day mission.

  6. STS-113 P1 Truss payload in the SSPF

    NASA Technical Reports Server (NTRS)

    2002-01-01

    KENNEDY SPACE CENTER, FLA. -- Inside the Space Station Processing Facility, technicians prepare the P1 Truss Segment to be hooked to the overhead crane and moved toward the payload canister. The P1 truss is the primary payload for Mission STS-113. It is the first port truss segment which will be attached to the Station's central truss segment, S0. Once delivered, the P1 truss will remain stowed until flight 12A.1. The mission will also deliver the Expedition 6 crew to the Station and return Expedition 5 to Earth. Space Shuttle Endeavour is scheduled to launch no earlier than Nov. 10 on the 11-day mission.

  7. STS-113 P1 Truss payload in the SSPF

    NASA Technical Reports Server (NTRS)

    2002-01-01

    KENNEDY SPACE CENTER, FLA. -- Inside the Space Station Processing Facility, the P1 Truss Segment is moved by overhead crane through the highbay toward the payload canister. The P1 truss is the primary payload for Mission STS-113. It is the first port truss segment which will be attached to the Station'''s central truss segment, S0. Once delivered, the P1 truss will remain stowed until flight 12A.1. The mission will also deliver the Expedition 6 crew to the Station and return Expedition 5 to Earth. Space Shuttle Endeavour is scheduled to launch no earlier than Nov. 10 on the 11-day mission.

  8. 18. 80 foot pony truss detail of the lower ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    18. 80 foot pony truss - detail of the lower cord pin connection, typical of the 80 foot trusses and similar to the 64 foot truss, where the vertical lace post joins the upper and lower chords. There are two pair of each 80 foot truss and a single pair on the 64 foot truss for a total of 22. The view also shows the chord eye bar and eye rod along with the diagonal bar and rod members. The rod hanging diagonally to the left is a broken lateral member. A four inch conduit is also in view. - Weidemeyer Bridge, Spanning Thomes Creek at Rawson Road, Corning, Tehama County, CA

  9. Adaptive structures for fixed and rotary wing aircraft

    NASA Astrophysics Data System (ADS)

    Martin, Willi; Jänker, Peter; Siemetzki, Markus; Lorkowski, Thomas; Grohmann, Boris; Maier, Rudolf; Maucher, Christoph; Klöppel, Valentin; Enenkl, Bernhard; Roth, Dieter; Hansen, Heinz

    2007-07-01

    Since more than 10 years EADS Innovation Works, which is the corporate research centre of EADS (European Aeronautic Defence and Space Company), is investigating smart materials and adaptive structures for aircraft in cooperation with EADS business units. Focus of research efforts are adaptive systems for shape control, noise reduction and vibration control of both fixed and rotary wing aircraft as well as for lift optimisation of fixed wing aircraft. Two outstanding adaptive systems which have been pushed ahead in cooperation with Airbus Germany and Eurocopter Germany are adaptive servo flaps for helicopter rotor blades and innovative high lift devices for fixed wing aircraft which both were tested in flight for the first time representing world premieres. In this paper various examples of adaptive systems are presented which were developed and realized by EADS in recent years.

  10. Damage assessment of the truss system with uncertainty using frequency response function based damage identification method

    NASA Astrophysics Data System (ADS)

    Zhao, Jie; DeSmidt, Hans; Yao, Wei

    2015-04-01

    A novel vibration-based damage identification methodology for the truss system with mass and stiffness uncertainties is proposed and demonstrated. This approach utilizes the damaged-induced changes of frequency response functions (FRF) to assess the severity and location of the structural damage in the system. The damage identification algorithm is developed basing on the least square and Newton-Raphson methods. The dynamical model of system is built using finite element method and Lagrange principle while the crack model is based on fracture mechanics. The method is synthesized via numerical examples for a truss system to demonstrate the effectiveness in detecting both stiffness and mass uncertainty existed in the system.

  11. Transformational part-count in layered octahedral-tetrahedral truss configurations

    NASA Technical Reports Server (NTRS)

    Lalvani, Haresh

    1990-01-01

    The number of component part (nodes, struts and panels) termed part count, is an important factor in the design, manufacture, and assembly of modular space structures. Part count expressions are presented for a variety of profiles derived from the layered octahedral-tetrahedral truss configuration. Referred to as the tetrahedral truss in the NASA projects, this specific geometry has been used in several missions. The general expressions presented here transforms to others as one profile changes to another. Such transformational part count relations provide a measure of flexibility and generality, and may be useful when dealing with a wider range of geometric configurations.

  12. A crane moves toward the S0 truss to transfer it to a workstand in the O&C Bldg.

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Inside the Operations and Checkout Bldg. (O&C), an overhead crane is centered over the S0 truss segment before lowering. The crane will move it to a workstand in the O&C where it will undergo processing. In the foreground is the protective cover just removed. During the processing, the Canadian Mobile Transporter, power distribution system modules, a heat pipe radiator for cooling, computers, and a pair of rate gyroscopes will be installed. Four Global Positioning System antennas are already installed. A 44- by 15-foot structure weighing 30,800 pounds when fully outfitted and ready for launch, the truss will be at the center of the ISS 10-truss, girderlike structure that will ultimately extend the length of a football field. Eventually the S0 truss will be attached to the U.S. Lab, 'Destiny,' which is scheduled to be added to the ISS in April 2000. Later, other trusses will be attached to the S0 on-orbit. The S0 truss is scheduled to be launched in the first quarter of 2001 on mission STS-108.

  13. Adaptive Crystal Structures: CuAu and NiPt

    NASA Astrophysics Data System (ADS)

    Sanati, M.; Wang, L. G.; Zunger, Alex

    2003-01-01

    We discover that Au-rich Cu1-xAux and Pt-rich Ni1-xPtx contain a composition range in which there is a quasicontinuum of stable, ordered “adaptive structures” made of (001) repeat units of simple structural motifs. This is found by searching ˜3×106 different fcc configurations whose energies are parametrized via a “cluster expansion” of first-principles-calculated total energies of just a few structures. This structural adaptivity is explained in terms of an anisotropic, long-range strain energy.

  14. Finite element analysis of a deployable space structure

    NASA Technical Reports Server (NTRS)

    Hutton, D. V.

    1982-01-01

    To assess the dynamic characteristics of a deployable space truss, a finite element model of the Scientific Applications Space Platform (SASP) truss has been formulated. The model incorporates all additional degrees of freedom associated with the pin-jointed members. Comparison of results with SPAR models of the truss show that the joints of the deployable truss significantly affect the vibrational modes of the structure only if the truss is relatively short.

  15. Dynamics of adaptive structures: Design through simulations

    NASA Technical Reports Server (NTRS)

    Park, K. C.; Alexander, S.

    1993-01-01

    The use of a helical bi-morph actuator/sensor concept by mimicking the change of helical waveform in bacterial flagella is perhaps the first application of bacterial motions (living species) to longitudinal deployment of space structures. However, no dynamical considerations were analyzed to explain the waveform change mechanisms. The objective is to review various deployment concepts from the dynamics point of view and introduce the dynamical considerations from the outset as part of design considerations. Specifically, the impact of the incorporation of the combined static mechanisms and dynamic design considerations on the deployment performance during the reconfiguration stage is studied in terms of improved controllability, maneuvering duration, and joint singularity index. It is shown that intermediate configurations during articulations play an important role for improved joint mechanisms design and overall structural deployability.

  16. A continuum model for interconnected lattice trusses

    NASA Technical Reports Server (NTRS)

    Balakrishnan, A. V.

    1992-01-01

    A continuum model for interconnected lattice trusses based on the 1D Timoshenko beam approximation is developed using the NASA-LRC Phase Zero Evolutionary Model. The continuum model dynamics is presented in the canonical wave-equation form in a Hilbert space.

  17. Structured Adaptive Mesh Refinement Application Infrastructure

    2010-07-15

    SAMRAI is an object-oriented support library for structured adaptice mesh refinement (SAMR) simulation of computational science problems, modeled by systems of partial differential equations (PDEs). SAMRAI is developed and maintained in the Center for Applied Scientific Computing (CASC) under ASCI ITS and PSE support. SAMRAI is used in a variety of application research efforts at LLNL and in academia. These applications are developed in collaboration with SAMRAI development team members.

  18. Guided Adaptive Image Smoothing via Directional Anisotropic Structure Measurement.

    PubMed

    Zang, Yu; Huang, Hua; Zhang, Lei

    2015-09-01

    Image smoothing prefers a good metric to identify dominant structures from textures adaptive of intensity contrast. In this paper, we drop on a novel directional anisotropic structure measurement (DASM) toward adaptive image smoothing. With observations on psychological perception regarding anisotropy, non-periodicity and local directionality, DASM can well characterize structures and textures independent on their contrast scales. By using such measurement as constraint, we design a guided adaptive image smoothing scheme by improving extrema localization and envelopes construction in a structure-aware manner. Our approach can well suppresses the staircase-like artifacts and blur of structures that appear in previous methods, which better suits structure-preserving image smoothing task. The algorithm is performed on a space-filling curve as the reduced domain, so it is very fast and much easy to implement in practice. We make comprehensive comparisons with previous state-of-the-art methods for a variety of applications. Experimental results demonstrate the merit using our DASM as metric to identify structures, and the effectiveness and efficiency of our adaptive image smoothing approach to produce commendable results. PMID:26357284

  19. Novel Control Effectors for Truss Braced Wing

    NASA Technical Reports Server (NTRS)

    White, Edward V.; Kapania, Rakesh K.; Joshi, Shiv

    2015-01-01

    At cruise flight conditions very high aspect ratio/low sweep truss braced wings (TBW) may be subject to design requirements that distinguish them from more highly swept cantilevered wings. High aspect ratio, short chord length and relative thinness of the airfoil sections all contribute to relatively low wing torsional stiffness. This may lead to aeroelastic issues such as aileron reversal and low flutter margins. In order to counteract these issues, high aspect ratio/low sweep wings may need to carry additional high speed control effectors to operate when outboard ailerons are in reversal and/or must carry additional structural weight to enhance torsional stiffness. The novel control effector evaluated in this study is a variable sweep raked wing tip with an aileron control surface. Forward sweep of the tip allows the aileron to align closely with the torsional axis of the wing and operate in a conventional fashion. Aft sweep of the tip creates a large moment arm from the aileron to the wing torsional axis greatly enhancing aileron reversal. The novelty comes from using this enhanced and controllable aileron reversal effect to provide roll control authority by acting as a servo tab and providing roll control through intentional twist of the wing. In this case the reduced torsional stiffness of the wing becomes an advantage to be exploited. The study results show that the novel control effector concept does provide roll control as described, but only for a restricted class of TBW aircraft configurations. For the configuration studied (long range, dual aisle, Mach 0.85 cruise) the novel control effector provides significant benefits including up to 12% reduction in fuel burn.

  20. Adaptive structural vibration control of acoustic deflector

    NASA Astrophysics Data System (ADS)

    Ostasevicius, Vytautas; Palevicius, Arvydas; Ragulskis, Minvydas; Dagys, Donatas; Janusas, Giedrius

    2004-06-01

    Vehicle interior acoustics became an important design criterion. Both legal restrictions and the growing demand for comfort, force car manufacturers to optimize the vibro-acoustic behavior of their products. The main source of noise is, of course, the engine, but sometimes some ill-designed cover or other shell structure inside the car resonates and makes unpredicted noise. To avoid this, we must learn the genesis mechanism of such vibrations, having as subject complex 3D shells. The swift development of computer technologies opens the possibility to numerically predict and optimize the vibrations and noises.

  1. A mobile work station concept for mechanically aided astronaut assembly of large space trusses

    NASA Technical Reports Server (NTRS)

    Heard, W. L., Jr.; Bush, H. G.; Wallson, R. E.; Jensen, J. K.

    1983-01-01

    This report presents results of a series of truss assembly tests conducted to evaluate a mobile work station concept intended to mechanically assist astronaut manual assembly of erectable space trusses. The tests involved assembly of a tetrahedral truss beam by a pair of test subjects with and without pressure (space) suits, both in Earth gravity and in simulated zero gravity (neutral buoyancy in water). The beam was assembled from 38 identical graphite-epoxy nestable struts, 5.4 m in length with aluminum quick-attachment structural joints. Struts and joints were designed to closely simulate flight hardware. The assembled beam was approximately 16.5 m long and 4.5 m on each of the four sides of its diamond-shaped cross section. The results show that average in-space assembly rates of approximately 38 seconds per strut can be expected for struts of comparable size. This result is virtually independent of the overall size of the structure being assembled. The mobile work station concept would improve astronaut efficiency for on-orbit manual assembly of truss structures, and also this assembly-line method is highly competitive with other construction methods being considered for large space structures.

  2. STS-110 M.S. Morin and Walheim with S0 Truss

    NASA Technical Reports Server (NTRS)

    2002-01-01

    KENNEDY SPACE CENTER, FLA. - STS-110 Mission Specialists Lee Morin and Rex Walheim look up at the S0 Integrated Truss Structure, part of the payload on their mission to the International Space Station. Crew members are at KSC for Terminal Countdown Demonstration Test activities that include the payload familiarization and a simulated launch countdown. Mission STS-110 is scheduled for launch April 4.

  3. Residual mode filters and adaptive control in large space structures

    NASA Technical Reports Server (NTRS)

    Davidson, Roger A.; Balas, Mark J.

    1989-01-01

    One of the most difficult problems in controlling large systems and structures is compensating for the destructive interaction which can occur between the reduced-order model (ROM) of the plant, which is used by the controller, and the unmodeled dynamics of the plant, often called the residual modes. The problem is more significant in the case of large space structures because their naturally light damping and high performance requirements lead to more frequent, destructive residual mode interaction (RMI). Using the design/compensation technique of residual mode filters (RMF's), effective compensation of RMI can be accomplished in a straightforward manner when using linear controllers. The use of RMF's has been shown to be effective for a variety of large structures, including a space-based laser and infinite dimensional systems. However, the dynamics of space structures is often uncertain and may even change over time due to on-orbit erosion from space debris and corrosive chemicals in the upper atmosphere. In this case, adaptive control can be extremely beneficial in meeting the performance requirements of the structure. Adaptive control for large structures is also based on ROM's and so destructive RMI may occur. Unfortunately, adaptive control is inherently nonlinear, and therefore the known results of RMF's cannot be applied. The purpose is to present the results of new research showing the effects of RMI when using adaptive control and the work which will hopefully lead to RMF compensation of this problem.

  4. Block-structured adaptive mesh refinement - theory, implementation and application

    SciTech Connect

    Deiterding, Ralf

    2011-01-01

    Structured adaptive mesh refinement (SAMR) techniques can enable cutting-edge simulations of problems governed by conservation laws. Focusing on the strictly hyperbolic case, these notes explain all algorithmic and mathematical details of a technically relevant implementation tailored for distributed memory computers. An overview of the background of commonly used finite volume discretizations for gas dynamics is included and typical benchmarks to quantify accuracy and performance of the dynamically adaptive code are discussed. Large-scale simulations of shock-induced realistic combustion in non-Cartesian geometry and shock-driven fluid-structure interaction with fully coupled dynamic boundary motion demonstrate the applicability of the discussed techniques for complex scenarios.

  5. Minimum mass design of large-scale space trusses subjected to thermal gradients

    NASA Technical Reports Server (NTRS)

    Williams, R. Brett; Agnes, Gregory S.

    2006-01-01

    Lightweight, deployable trusses are commonly used to support space-borne instruments including RF reflectors, radar panels, and telescope optics. While in orbit, these support structures are subjected to thermal gradients that vary with altitude, location in orbit, and self-shadowing. Since these instruments have tight dimensional-stability requirements, their truss members are often covered with multi-layer insulation (MLI) blankets to minimize thermal distortions. This paper develops a radiation heat transfer model to predict the thermal gradient experienced by a triangular truss supporting a long, linear radar panel in Medium Earth Orbit (MEO). The influence of self-shadowing effects of the radar panel are included in the analysis, and the influence of both MLI thickness and outer covers/coatings on the magnitude of the thermal gradient are formed into a simple, two-dimensional analysis. This thermal model is then used to size and estimate the structural mass of a triangular truss that meets a given set of structural requirements.

  6. Geometric and Static Analysis of the Historical Trusses in Roman Catholic Church of the Holy Kozma and Damian in the Abramová Village

    NASA Astrophysics Data System (ADS)

    Krušinský, Peter; Capková, Eva; Gocál, Jozef; Holešová, Michaela

    2015-12-01

    The truss of the Roman Catholic Church of the holy Kozma and Damian was managed to date to the year 1470/71d. It represents one of the few well-preserved medieval structures in this region. The form of roofs is a typical for rafter collar-beam construction without stiffening frame. The geometrical analysis of the main roofs trusses is based on logical dependencies and a description of a process in the truss design, pointing to evaluative relations resulting especially from the Pythagorean Geometry. Consequently, a spatial numerical model of the roof structure was developed in order to perform a static analysis of the roof structure in accordance with present standards. Due to the fact that during the diagnostic survey there were noted some missing structural elements in the roof construction (angle braces), in further analysis, an attention was paid to the importance of the selected structural elements and their role in the construction of the truss itself.

  7. Structural Adaptation of Normal and Tumour Vascular Networks

    PubMed Central

    Secomb, Timothy W.; Dewhirst, Mark W.; Pries, Axel R.

    2012-01-01

    Vascular networks are dynamic structures, adapting to changing conditions by structural remodelling of vessel diameters and by growth of new vessels and regression of existing vessels. The vast number of blood vessels in the circulatory system, more than 109, implies that vessels’ arrangement and structure are not under individual genetic control but emerge as a result of generic responses of each segment to the various stimuli that it experiences. To obtain insight into the types of response that are needed, a network-oriented approach has been used, in which theoretical models are used to simulate structural adaptation in vascular networks, and the results are compared with experimental observations. With regard to the structural control of vessel diameters, this approach shows that responses to both haemodynamic and metabolic stimuli are needed for the formation of functionally adequate and efficient network structures. Furthermore, information transfer in both upstream and downstream directions is essential for balancing flows between long and short flow pathways. Otherwise, functional shunting occurs, that is, short pathways become enlarged and flow bypasses longer pathways. Information transfer in the upstream direction is achieved by conducted responses communicated along vessel walls. Simulations of structural adaptation in tumour microvascular networks indicate that impaired vascular communication, resulting in functional shunting, may be an important factor causing the dysfunctional microcirculation and local hypoxia typically observed in tumours. Anti-angiogenic treatment of tumours may restore vascular communication and thereby improve or normalize flow distribution in tumour vasculature. PMID:21995550

  8. Computerized Adaptive Testing with Multiple-Form Structures

    ERIC Educational Resources Information Center

    Armstrong, Ronald D.; Jones, Douglas H.; Koppel, Nicole B.; Pashley, Peter J.

    2004-01-01

    A multiple-form structure (MFS) is an ordered collection or network of testlets (i.e., sets of items). An examinee's progression through the network of testlets is dictated by the correctness of an examinee's answers, thereby adapting the test to his or her trait level. The collection of paths through the network yields the set of all possible…

  9. Wireless Laser Range Finder System for Vertical Displacement Monitoring of Mega-Trusses during Construction

    PubMed Central

    Park, Hyo Seon; Son, Sewook; Choi, Se Woon; Kim, Yousok

    2013-01-01

    As buildings become increasingly complex, construction monitoring using various sensors is urgently needed for both more systematic and accurate safety management and high-quality productivity in construction. In this study, a monitoring system that is composed of a laser displacement sensor (LDS) and a wireless sensor node was proposed and applied to an irregular building under construction. The subject building consists of large cross-sectional members, such as mega-columns, mega-trusses, and edge truss, which secured the large spaces. The mega-trusses and edge truss that support this large space are of the cantilever type. The vertical displacement occurring at the free end of these members was directly measured using an LDS. To validate the accuracy and reliability of the deflection data measured from the LDS, a total station was also employed as a sensor for comparison with the LDS. In addition, the numerical simulation result was compared with the deflection obtained from the LDS and total station. Based on these investigations, the proposed wireless displacement monitoring system was able to improve the construction quality by monitoring the real-time behavior of the structure, and the applicability of the proposed system to buildings under construction for the evaluation of structural safety was confirmed. PMID:23648650

  10. Wireless laser range finder system for vertical displacement monitoring of mega-trusses during construction.

    PubMed

    Park, Hyo Seon; Son, Sewook; Choi, Se Woon; Kim, Yousok

    2013-01-01

    As buildings become increasingly complex, construction monitoring using various sensors is urgently needed for both more systematic and accurate safety management and high-quality productivity in construction. In this study, a monitoring system that is composed of a laser displacement sensor (LDS) and a wireless sensor node was proposed and applied to an irregular building under construction. The subject building consists of large cross-sectional members, such as mega-columns, mega-trusses, and edge truss, which secured the large spaces. The mega-trusses and edge truss that support this large space are of the cantilever type. The vertical displacement occurring at the free end of these members was directly measured using an LDS. To validate the accuracy and reliability of the deflection data measured from the LDS, a total station was also employed as a sensor for comparison with the LDS. In addition, the numerical simulation result was compared with the deflection obtained from the LDS and total station. Based on these investigations, the proposed wireless displacement monitoring system was able to improve the construction quality by monitoring the real-time behavior of the structure, and the applicability of the proposed system to buildings under construction for the evaluation of structural safety was confirmed. PMID:23648650

  11. Adaptive modelling of structured molecular representations for toxicity prediction

    NASA Astrophysics Data System (ADS)

    Bertinetto, Carlo; Duce, Celia; Micheli, Alessio; Solaro, Roberto; Tiné, Maria Rosaria

    2012-12-01

    We investigated the possibility of modelling structure-toxicity relationships by direct treatment of the molecular structure (without using descriptors) through an adaptive model able to retain the appropriate structural information. With respect to traditional descriptor-based approaches, this provides a more general and flexible way to tackle prediction problems that is particularly suitable when little or no background knowledge is available. Our method employs a tree-structured molecular representation, which is processed by a recursive neural network (RNN). To explore the realization of RNN modelling in toxicological problems, we employed a data set containing growth impairment concentrations (IGC50) for Tetrahymena pyriformis.

  12. Adaptive-Control Experiments On A Large Flexible Structure

    NASA Technical Reports Server (NTRS)

    Ih, Che-Hang C.; Bayard, David S.; Wang, Shyh J.; Eldred, Daniel B.

    1990-01-01

    Antennalike flexible structure built for research in advanced technology including suppression of vibrations and control of initial deflections. Structure instrumented with sensors and actuators connected to digital electronic control system, programmed with control algorithms to be tested. Particular attention in this research focused on direct model-reference adaptive-control algorithm based on command generator tracker theory. Built to exhibit multiple vibrational modes, low modal frequencies, and low structural damping. Made three-dimensional so complicated interactions among components of structure and control system investigated.

  13. 33. 100 foot through truss view is a detail ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    33. 100 foot through truss - view is a detail of the underside of the north west corner of the second through truss. Shows the upper chord pin connection, end post, lateral lace strut and sway bracing. This is typical of all four corners of each through truss for this bridge for a total of eight. - Weidemeyer Bridge, Spanning Thomes Creek at Rawson Road, Corning, Tehama County, CA

  14. 21. 80 foot pony truss view is from the ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    21. 80 foot pony truss - view is from the deck, looking down to the junction of the two pony trusses, showing the top of the lower chord pin connection on top of the replacement pier. Also shown is some deck surface and an electrical conduit. This is typical of the junction of all the pony trusses. - Weidemeyer Bridge, Spanning Thomes Creek at Rawson Road, Corning, Tehama County, CA

  15. 19. 80 foot pony truss view of upper chord ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    19. 80 foot pony truss - view of upper chord pin connection at the end post, typical of the five 80 foot trusses and similar to the 64 foot tress. There are two pair per pony truss for a total of 24. Shown are the vertical lace post, end post, top chord member, and a diagonal member. - Weidemeyer Bridge, Spanning Thomes Creek at Rawson Road, Corning, Tehama County, CA

  16. 35. SECOND FLOOR WEST ROOM LOOKING NORTH. The two trusses ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    35. SECOND FLOOR WEST ROOM LOOKING NORTH. The two trusses above this room date from 1812. They differ from the 1755 salvaged trusses in that they are made of pine rather than poplar, their numbering system differs, and they do not have pockets for joists. These two trusses were added to extend the plan of the building when it was re-erected in 1812. - Twelfth Street Meeting House, 20 South Twelfth Street, Philadelphia, Philadelphia County, PA

  17. Adaptive control of large space structures using recursive lattice filters

    NASA Technical Reports Server (NTRS)

    Sundararajan, N.; Goglia, G. L.

    1985-01-01

    The use of recursive lattice filters for identification and adaptive control of large space structures is studied. Lattice filters were used to identify the structural dynamics model of the flexible structures. This identification model is then used for adaptive control. Before the identified model and control laws are integrated, the identified model is passed through a series of validation procedures and only when the model passes these validation procedures is control engaged. This type of validation scheme prevents instability when the overall loop is closed. Another important area of research, namely that of robust controller synthesis, was investigated using frequency domain multivariable controller synthesis methods. The method uses the Linear Quadratic Guassian/Loop Transfer Recovery (LQG/LTR) approach to ensure stability against unmodeled higher frequency modes and achieves the desired performance.

  18. Structured near-optimal channel-adapted quantum error correction

    NASA Astrophysics Data System (ADS)

    Fletcher, Andrew S.; Shor, Peter W.; Win, Moe Z.

    2008-01-01

    We present a class of numerical algorithms which adapt a quantum error correction scheme to a channel model. Given an encoding and a channel model, it was previously shown that the quantum operation that maximizes the average entanglement fidelity may be calculated by a semidefinite program (SDP), which is a convex optimization. While optimal, this recovery operation is computationally difficult for long codes. Furthermore, the optimal recovery operation has no structure beyond the completely positive trace-preserving constraint. We derive methods to generate structured channel-adapted error recovery operations. Specifically, each recovery operation begins with a projective error syndrome measurement. The algorithms to compute the structured recovery operations are more scalable than the SDP and yield recovery operations with an intuitive physical form. Using Lagrange duality, we derive performance bounds to certify near-optimality.

  19. Recent Developments in Smart Adaptive Structures for Solar Sailcraft

    NASA Technical Reports Server (NTRS)

    Worton, M. S.; Kim, Y. K.; Oakley, J.; Adetona, O.; Keel, L. H.

    2007-01-01

    The "Smart Adaptive Structures for Solar Sailcraft" development activity at MSFC has investigated issues associated with understanding how to model and scale the subsystem and multi-body system dynamics of a gossamer solar sailcraft with the objective of designing sailcraft attitude control systems. This research and development activity addressed three key tasks that leveraged existing facilities and core competencies of MSFC to investigate dynamics and control issues of solar sails. Key aspects of this effort included modeling and testing of a 30 m deployable boom; modeling of the multi-body system dynamics of a gossamer sailcraft; investigation of control-structures interaction for gossamer sailcraft; and development and experimental demonstration of adaptive control technologies to mitigate control-structures interaction.

  20. Adaptive control of large space structures using recursive lattice filters

    NASA Technical Reports Server (NTRS)

    Goglia, G. L.

    1985-01-01

    The use of recursive lattice filters for identification and adaptive control of large space structures was studied. Lattice filters are used widely in the areas of speech and signal processing. Herein, they are used to identify the structural dynamics model of the flexible structures. This identified model is then used for adaptive control. Before the identified model and control laws are integrated, the identified model is passed through a series of validation procedures and only when the model passes these validation procedures control is engaged. This type of validation scheme prevents instability when the overall loop is closed. The results obtained from simulation were compared to those obtained from experiments. In this regard, the flexible beam and grid apparatus at the Aerospace Control Research Lab (ACRL) of NASA Langley Research Center were used as the principal candidates for carrying out the above tasks. Another important area of research, namely that of robust controller synthesis, was investigated using frequency domain multivariable controller synthesis methods.

  1. An adaptive learning control system for large flexible structures

    NASA Technical Reports Server (NTRS)

    Thau, F. E.

    1985-01-01

    The objective of the research has been to study the design of adaptive/learning control systems for the control of large flexible structures. In the first activity an adaptive/learning control methodology for flexible space structures was investigated. The approach was based on using a modal model of the flexible structure dynamics and an output-error identification scheme to identify modal parameters. In the second activity, a least-squares identification scheme was proposed for estimating both modal parameters and modal-to-actuator and modal-to-sensor shape functions. The technique was applied to experimental data obtained from the NASA Langley beam experiment. In the third activity, a separable nonlinear least-squares approach was developed for estimating the number of excited modes, shape functions, modal parameters, and modal amplitude and velocity time functions for a flexible structure. In the final research activity, a dual-adaptive control strategy was developed for regulating the modal dynamics and identifying modal parameters of a flexible structure. A min-max approach was used for finding an input to provide modal parameter identification while not exceeding reasonable bounds on modal displacement.

  2. Design optimization in underground coal systems. Volume VIII. The roof truss: an analysis with applications to mine design. Final technical report

    SciTech Connect

    Not Available

    1981-02-28

    The purpose of this research effort was to optimize the application of the roof truss for use in supporting coal mine roofs. Model analysis using two-dimensinal, body-loaded, photoelastic models was supplemented with field data and testing. A detailed literature review was also undertaken. The detailed analysis of photoelastic models of roof trusses was pursued by varying a number of the truss parameters - center-span installation angles and blocking-point configuration. In obtaining reduced deflection, the best support was achieved employing an angle of installation of 90/sup 0/. However, due to roof failute considerations, the recommended angle of installation was 45/sup 0/. Blocking points were shown to have an effect on roof-support capacity as well as truss span, and field tests indicated that the installation of a roof truss actually raised the roof. Also, from field measurements, it was shown that all sections of the arch carried the same load. The use of the roof truss as a major support principle and device in underground coal mines was confined. The installation angle should be 45/sup 0/ in any specified roof span. Blocking is an essential part of the arch installation and should be carefully implemented to insure maximum efficiency of the arch. It was concluded that: the truss installation of 45/sup 0/ produces maximum benefit when the overall stability of the roof is considered; the two-dimensional, body-loaded photoelastic model may be used to analyze underground structures; in underground installations, all components of the roof truss structure sustain the same load; and uplift of the roof may be achieved during installation of the roof truss system.

  3. Adaptive state estimation for control of flexible structures

    NASA Technical Reports Server (NTRS)

    Chen, Chung-Wen; Huang, Jen-Kuang

    1990-01-01

    This paper proposes a new approach of obtaining adaptive state estimation of a system in the presence of unknown system disturbances and measurement noise. In the beginning, a non-optimal Kalman filter with arbitrary initial guess for the process and measurement noises is implemented. At the same time, an adaptive transversal predictor (ATP) based on the recursive least-squares (RLS) algorithm is used to yield optimal one- to p- step-ahead output predictions using the previous input/output data. Referring to these optimal predictions the Kalman filter gain is updated and the performance of the state estimation is thus improved. If forgetting factor is implemented in the recursive least-squares algorithm, this method is also capable of dealing with the situation when the noise statistics are slowly time-varying. This feature makes this new approach especially suitable for the control of flexible structures. A numerical example demonstrates the feasibility of this real time adaptive state estimation method.

  4. Software abstractions and computational issues in parallel structure adaptive mesh methods for electronic structure calculations

    SciTech Connect

    Kohn, S.; Weare, J.; Ong, E.; Baden, S.

    1997-05-01

    We have applied structured adaptive mesh refinement techniques to the solution of the LDA equations for electronic structure calculations. Local spatial refinement concentrates memory resources and numerical effort where it is most needed, near the atomic centers and in regions of rapidly varying charge density. The structured grid representation enables us to employ efficient iterative solver techniques such as conjugate gradient with FAC multigrid preconditioning. We have parallelized our solver using an object- oriented adaptive mesh refinement framework.

  5. roof truss detail, historic strap hinge detail Chopawamsic Recreational ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    roof truss detail, historic strap hinge detail - Chopawamsic Recreational Demonstration Area - Cabin Camp 1, Main Arts and Crafts Lodge, Prince William Forest Park, Triangle, Prince William County, VA

  6. Design of a welded joint for robotic, on-orbit assembly of space trusses

    NASA Technical Reports Server (NTRS)

    Rule, William K.

    1992-01-01

    In the future, some spacecraft will be so large that they must be assembled on-orbit. These spacecraft will be used for such tasks as manned missions to Mars or used as orbiting platforms for monitoring the Earth or observing the universe. Some large spacecraft will probably consist of planar truss structures to which will be attached special purpose, self-contained modules. The modules will most likely be taken to orbit fully outfitted and ready for use in heavy-lift launch vehicles. The truss members will also similarly be taken to orbit, but most unassembled. The truss structures will need to be assembled robotically because of the high costs and risks of extra-vehicular activities. Some missions will involve very large loads. To date, very few structures of any kind have been constructed in space. Two relatively simple trusses were assembled in the Space Shuttle bay in late 1985. Here the development of a design of a welded joint for on-orbit, robotic truss assembly is described. Mechanical joints for this application have been considered previously. Welded joints have the advantage of allowing the truss members to carry fluids for active cooling or other purposes. In addition, welded joints can be made more efficient structurally than mechanical joints. Also, welded joints require little maintenance (will not shake loose), and have no slop which would cause the structure to shudder under load reversal. The disadvantages of welded joints are that a more sophisticated assembly robot is required, weld flaws may be difficult to detect on-orbit, the welding process is hazardous, and welding introduces contamination to the environment. In addition, welded joints provide less structural damping than do mechanical joints. Welding on-orbit was first investigated aboard a Soyuz-6 mission in 1969 and then during a Skylab electron beam welding experiment in 1973. A hand held electron beam welding apparatus is currently being prepared for use on the MIR space station

  7. Design of a welded joint for robotic, on-orbit assembly of space trusses

    NASA Astrophysics Data System (ADS)

    Rule, William K.

    1992-12-01

    In the future, some spacecraft will be so large that they must be assembled on-orbit. These spacecraft will be used for such tasks as manned missions to Mars or used as orbiting platforms for monitoring the Earth or observing the universe. Some large spacecraft will probably consist of planar truss structures to which will be attached special purpose, self-contained modules. The modules will most likely be taken to orbit fully outfitted and ready for use in heavy-lift launch vehicles. The truss members will also similarly be taken to orbit, but most unassembled. The truss structures will need to be assembled robotically because of the high costs and risks of extra-vehicular activities. Some missions will involve very large loads. To date, very few structures of any kind have been constructed in space. Two relatively simple trusses were assembled in the Space Shuttle bay in late 1985. Here the development of a design of a welded joint for on-orbit, robotic truss assembly is described. Mechanical joints for this application have been considered previously. Welded joints have the advantage of allowing the truss members to carry fluids for active cooling or other purposes. In addition, welded joints can be made more efficient structurally than mechanical joints. Also, welded joints require little maintenance (will not shake loose), and have no slop which would cause the structure to shudder under load reversal. The disadvantages of welded joints are that a more sophisticated assembly robot is required, weld flaws may be difficult to detect on-orbit, the welding process is hazardous, and welding introduces contamination to the environment. In addition, welded joints provide less structural damping than do mechanical joints. Welding on-orbit was first investigated aboard a Soyuz-6 mission in 1969 and then during a Skylab electron beam welding experiment in 1973. A hand held electron beam welding apparatus is currently being prepared for use on the MIR space station

  8. Salvage of Failed Total Ankle Replacement Using a Custom Titanium Truss.

    PubMed

    Mulhern, Jennifer L; Protzman, Nicole M; White, Amari M; Brigido, Stephen A

    2016-01-01

    Subsidence of the talar component results in significant morbidity after total ankle replacement. When recognized, prompt revision could be needed to preserve the function of the implant; however, this is not always the case. In situations in which the implant cannot be revised, tibiotalocalcaneal arthrodesis might be necessary to salvage the extremity. The purpose of the present report is to describe the use of a custom titanium alloy truss to fill a bony void created by explantation of the implant components. Total ankle replacement was performed as the initial surgery to address end-stage osteoarthritis. Two years after the index procedure, the patient underwent revision of the polyethylene and talar components with subtalar arthrodesis secondary to progressive subtalar osteoarthritis and talar subsidence. The implant subsequently became infected and was removed. The patient underwent re-implantation after the infection had resolved, but significant talar subsidence required conversion to a tibiotalocalcaneal arthrodesis with a custom titanium alloy truss and retrograde intramedullary nail. At the most recent follow-up appointment, the patient was weightbearing on a stable extremity and pain free. Radiographic examination confirmed appropriate implant alignment and evidence of bone formation throughout the titanium truss. Although our results are restricted to a single case with initial, limited follow-up data, combining sound structural mechanics with an open architecture and unique texture, the custom titanium truss appears to maintain the limb length and promote healing across a large void. PMID:26884264

  9. Application of truss analysis for the quantification of changes in fish condition

    USGS Publications Warehouse

    Fitzgerald, Dean G.; Nanson, Jeffrey W.; Todd, Thomas N.; Davis, Bruce M.

    2002-01-01

    Conservation of skeletal structure and unique body ratios in fishes facilitated the development of truss analysis as a taxonomic tool to separate physically-similar species. The methodology is predicated on the measurement of across-body distances from a sequential series of connected polygons. Changes in body shape or condition among members of the same species can be quantified with the same technique, and we conducted a feeding experiment using yellow perch (Perca flavescens) to examine the utility of this approach. Ration size was used as a surrogate for fish condition, with fish receiving either a high (3.0% body wt/d) or a low ration (0.5%). Sequentially over our 11-week experiment, replicate ration groups of fish were removed and photographed while control fish were repeatedly weighed and measured. Standard indices of condition (total lipids, weight-length ratios, Fulton's condition) were compared to truss measurements determined from digitized pictures of fish. Condition indices showed similarity between rations while truss measures from the caudal region were important for quantifying changing body shape. These findings identify truss analysis as having use beyond traditional applications. It can potentially be used as a cheap, accurate, and precise descriptor of fish condition in the lab as shown here, and we hypothesize that it would be applicable in field studies.

  10. Adaptations in Electronic Structure Calculations in Heterogeneous Environments

    SciTech Connect

    Talamudupula, Sai

    2011-01-01

    Modern quantum chemistry deals with electronic structure calculations of unprecedented complexity and accuracy. They demand full power of high-performance computing and must be in tune with the given architecture for superior e ciency. To make such applications resourceaware, it is desirable to enable their static and dynamic adaptations using some external software (middleware), which may monitor both system availability and application needs, rather than mix science with system-related calls inside the application. The present work investigates scienti c application interlinking with middleware based on the example of the computational chemistry package GAMESS and middleware NICAN. The existing synchronous model is limited by the possible delays due to the middleware processing time under the sustainable runtime system conditions. Proposed asynchronous and hybrid models aim at overcoming this limitation. When linked with NICAN, the fragment molecular orbital (FMO) method is capable of adapting statically and dynamically its fragment scheduling policy based on the computing platform conditions. Signi cant execution time and throughput gains have been obtained due to such static adaptations when the compute nodes have very di erent core counts. Dynamic adaptations are based on the main memory availability at run time. NICAN prompts FMO to postpone scheduling certain fragments, if there is not enough memory for their immediate execution. Hence, FMO may be able to complete the calculations whereas without such adaptations it aborts.

  11. A three dimensional heart model based on anatomically aligned trusses.

    PubMed

    Witman, S; Gefen, A; Barnea, O

    2007-01-01

    A new approach for modeling and simulating the contraction of the heart is presented. The model is based on anatomical images and accounts for cardiac muscle fibers and their orientation. The heart is modeled as a structure built of trusses, each representing a group of myofibers with calculated deformations using matrix structural analysis. Three elements are represented; these are the contractile cardiac muscle, the elastic passive collagen, and intracardiac blood interacting with the heart's preload and afterload. Incompressibility of each element is preserved. The conduction system is simulated in the model by transferring the activating signal from one element to another or by Purkinje fibers activation. The method was demonstrated using a three-dimensional one-layer geometrical ventricle with orthogonal fibers and with anatomically oriented fibers. PMID:18002551

  12. Robot path planning for space-truss assembly

    NASA Technical Reports Server (NTRS)

    Muenger, Rolf; Sanderson, Arthur C.

    1992-01-01

    Construction, repair, and maintenance of space-based structures will require extensive planning of operations in order to effectively carry out these tasks. The path planning algorithm described here is a general approach to generating paths that guarantee collision avoidance for a single chain nonredundant or redundant robot. The algorithm uses a graph search of feasible points in position space, followed by a local potential field method that guarantees collision avoidance among objects, structures, and the robot arm as well as conformance to joint limit constraints. This algorithm is novel in its computation of goal attractive potential fields in Cartesian space, and computation of obstacle repulsive fields in robot joint space. These effects are combined to generate robot motion. Computation is efficiently implemented through the computation of the robot arm Jacobian and not the full inverse arm kinematics. These planning algorithms have been implemented and evaluated using existing space-truss designs, and are being integrated into the RPI-CIRSSE Testbed environment.

  13. Adaptive sensor array algorithm for structural health monitoring of helmet

    NASA Astrophysics Data System (ADS)

    Zou, Xiaotian; Tian, Ye; Wu, Nan; Sun, Kai; Wang, Xingwei

    2011-04-01

    The adaptive neural network is a standard technique used in nonlinear system estimation and learning applications for dynamic models. In this paper, we introduced an adaptive sensor fusion algorithm for a helmet structure health monitoring system. The helmet structure health monitoring system is used to study the effects of ballistic/blast events on the helmet and human skull. Installed inside the helmet system, there is an optical fiber pressure sensors array. After implementing the adaptive estimation algorithm into helmet system, a dynamic model for the sensor array has been developed. The dynamic response characteristics of the sensor network are estimated from the pressure data by applying an adaptive control algorithm using artificial neural network. With the estimated parameters and position data from the dynamic model, the pressure distribution of the whole helmet can be calculated following the Bazier Surface interpolation method. The distribution pattern inside the helmet will be very helpful for improving helmet design to provide better protection to soldiers from head injuries.

  14. Accuracy potentials for large space antenna structures

    NASA Technical Reports Server (NTRS)

    Hedgepeth, J. M.

    1980-01-01

    The relationships among materials selection, truss design, and manufacturing techniques in the interest of surface accuracies for large space antennas are discussed. Among the antenna configurations considered are: tetrahedral truss, pretensioned truss, and geodesic dome and radial rib structures. Comparisons are made of the accuracy achievable by truss and dome structure types for a wide variety of diameters, focal lengths, and wavelength of radiated signal, taking into account such deforming influences as solar heating-caused thermal transients and thermal gradients.

  15. Structural adaptations to diverse fighting styles in sexually selected weapons

    PubMed Central

    McCullough, Erin L.; Tobalske, Bret W.; Emlen, Douglas J.

    2014-01-01

    The shapes of sexually selected weapons differ widely among species, but the drivers of this diversity remain poorly understood. Existing explanations suggest weapon shapes reflect structural adaptations to different fighting styles, yet explicit tests of this hypothesis are lacking. We constructed finite element models of the horns of different rhinoceros beetle species to test whether functional specializations for increased performance under species-specific fighting styles could have contributed to the diversification of weapon form. We find that horns are both stronger and stiffer in response to species-typical fighting loads and that they perform more poorly under atypical fighting loads, which suggests weapons are structurally adapted to meet the functional demands of fighting. Our research establishes a critical link between weapon form and function, revealing one way male–male competition can drive the diversification of animal weapons. PMID:25201949

  16. Temporal and structural heterogeneities emerging in adaptive temporal networks

    NASA Astrophysics Data System (ADS)

    Aoki, Takaaki; Rocha, Luis E. C.; Gross, Thilo

    2016-04-01

    We introduce a model of adaptive temporal networks whose evolution is regulated by an interplay between node activity and dynamic exchange of information through links. We study the model by using a master equation approach. Starting from a homogeneous initial configuration, we show that temporal and structural heterogeneities, characteristic of real-world networks, spontaneously emerge. This theoretically tractable model thus contributes to the understanding of the dynamics of human activity and interaction networks.

  17. Segmentation of branching vascular structures using adaptive subdivision surface fitting

    NASA Astrophysics Data System (ADS)

    Kitslaar, Pieter H.; van't Klooster, Ronald; Staring, Marius; Lelieveldt, Boudewijn P. F.; van der Geest, Rob J.

    2015-03-01

    This paper describes a novel method for segmentation and modeling of branching vessel structures in medical images using adaptive subdivision surfaces fitting. The method starts with a rough initial skeleton model of the vessel structure. A coarse triangular control mesh consisting of hexagonal rings and dedicated bifurcation elements is constructed from this skeleton. Special attention is paid to ensure a topological sound control mesh is created around the bifurcation areas. Then, a smooth tubular surface is obtained from this coarse mesh using a standard subdivision scheme. This subdivision surface is iteratively fitted to the image. During the fitting, the target update locations of the subdivision surface are obtained using a scanline search along the surface normals, finding the maximum gradient magnitude (of the imaging data). In addition to this surface fitting framework, we propose an adaptive mesh refinement scheme. In this step the coarse control mesh topology is updated based on the current segmentation result, enabling adaptation to varying vessel lumen diameters. This enhances the robustness and flexibility of the method and reduces the amount of prior knowledge needed to create the initial skeletal model. The method was applied to publicly available CTA data from the Carotid Bifurcation Algorithm Evaluation Framework resulting in an average dice index of 89.2% with the ground truth. Application of the method to the complex vascular structure of a coronary artery tree in CTA and to MRI images were performed to show the versatility and flexibility of the proposed framework.

  18. Experimental implementation of adaptive control for flexible space structures

    NASA Technical Reports Server (NTRS)

    Mcgraw, Gary A.

    1988-01-01

    On-going research at The Aerospace Corporation studying the feasibility of applying adaptive control methodologies to the control of flexible space structures is described. A laboratory testbed was established to test system identification and control approaches. The laboratory set-up and controller design approach are discussed. The ARX least squares parameter estimation technique is analyzed in terms of frequency domain transfer function bias error. This analysis approach enables the determination of the effects of sampling rate, sensor type, and data prefiltering on the estimation performance. The ability to identify space structure dynamics over a range of frequencies is shown to be heavily dependent on these factors.

  19. Model of adaptive temporal development of structured finite systems

    NASA Astrophysics Data System (ADS)

    Patera, Jiri; Shaw, Gordon L.; Slansky, Richard; Leng, Xiaodan

    1989-07-01

    The weight systems of level-zero representations of affine Kac-Moody algebras provide an appropriate kinematical framework for studying structured finite systems with adaptive temporal development. Much of the structure is determined by Lie algebra theory, so it is possible to restrict greatly the connection space and analytic results are possible. The time development of these systems often evolves to cyclic temporal-spatial patterns, depending on the definition of the dynamics. The purpose of this paper is to set up the mathematical formalism for this ``memory in Lie algebras'' class of models. An illustration is used to show the kinds of complex behavior that occur in simple cases.

  20. 9. OBLIQUE VIEW, PARTIAL WEST SPAN, FROM SOUTHWEST, SHOWING TRUSS ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    9. OBLIQUE VIEW, PARTIAL WEST SPAN, FROM SOUTHWEST, SHOWING TRUSS PANELS AND SOLID CONFIGURATION OF TRUSS MEMBERS, INCLUDING POLYGONAL TOP CHORD, VERTICAL AND DIAGONAL MEMBERS, AND CROSS-STRUTS - Glendale Road Bridge, Spanning Deep Creek Lake on Glendale Road, McHenry, Garrett County, MD

  1. 24. 100 foot through truss view is from the ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    24. 100 foot through truss - view is from the deck, looking down to the junction of the two through trusses where they are attached to pier #7. There are only two of these, located on each end of pier #7. - Weidemeyer Bridge, Spanning Thomes Creek at Rawson Road, Corning, Tehama County, CA

  2. 36. 100 foot through truss view is the outside ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    36. 100 foot through truss - view is the outside of an upper chord pin connection showing the vertical post and a diagonal member. There are four of these for each of two through trusses for a total of eight. - Weidemeyer Bridge, Spanning Thomes Creek at Rawson Road, Corning, Tehama County, CA

  3. 27. 100 foot through truss a typical lower chord ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    27. 100 foot through truss - a typical lower chord pin connection, located below the vertical member junction with the end post and upper chord. View shows one diagonal member. There are four of these per through truss for a total of 8, also shows the four inch conduit. - Weidemeyer Bridge, Spanning Thomes Creek at Rawson Road, Corning, Tehama County, CA

  4. 7. 80 foot pony truss underside of bridge, looking ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    7. 80 foot pony truss - underside of bridge, looking north, showing the original pier and the outrigger type extension to raise and level the present-day support for the pony trusses. - Weidemeyer Bridge, Spanning Thomes Creek at Rawson Road, Corning, Tehama County, CA

  5. 14. 64 foot pony truss view of a lower ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    14. 64 foot pony truss - view of a lower cord pin connection at the first vertical post, this truss has two pair of this connection for a total of four. - Weidemeyer Bridge, Spanning Thomes Creek at Rawson Road, Corning, Tehama County, CA

  6. VIEW OF CANTILEVER THROUGH TRUSS BRIDGE PORTALS AT JUNCTION BETWEEN ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW OF CANTILEVER THROUGH TRUSS BRIDGE PORTALS AT JUNCTION BETWEEN SIMPLE THROUGH TRUSS SPAN LOOKING SOUTHEAST TOWARD WEST BANK. - Huey P. Long Bridge, Spanning Mississippi River approximately midway between nine & twelve mile points upstream from & west of New Orleans, Jefferson, Jefferson Parish, LA

  7. 11. 100 foot through truss north east bearing abutment ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    11. 100 foot through truss - north east bearing abutment of the second through truss, showing that the bearing point is to the backmost position of the concrete pier. This bearing point is on a concrete extension of the original bearing point now covered by rock and soil. - Weidemeyer Bridge, Spanning Thomes Creek at Rawson Road, Corning, Tehama County, CA

  8. 24 CFR 3280.402 - Test procedure for roof trusses.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... the design. The top and bottom chords shall be braced and covered with the material, with connections... procedure, the top chord may be sheathed with 1/4 inch by 12 inch plywood strips. The plywood strips shall be at least long enough to cover the top chords of the trusses at the designated design truss...

  9. 13. ONE OF TWO LATERAL ROOF TRUSSES AND ROOF SUPPORT ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    13. ONE OF TWO LATERAL ROOF TRUSSES AND ROOF SUPPORT BEAMS OF SARATOGA GAS LIGHT COMPANY GASHOLDER NO. 2 HOUSE LOOKING WEST. THE WIRES AND BEAM AT RIGHT CENTER OF PHOTOGRAPH HAVE BEEN ADDED TO STABILIZE TRUSS SYSTEM - Saratoga Gas Light Company, Gasholder No. 2, Niagara Mohawk Power Corporation Substation Facility, intersection of Excelsior & East Avenues, Saratoga Springs, NY

  10. 12. CENTRAL ROOF TRUSS AND ROOF SUPPORT BEAMS OF SARATOGA ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    12. CENTRAL ROOF TRUSS AND ROOF SUPPORT BEAMS OF SARATOGA GAS LIGHT COMPANY GASHOLDER NO. 2 HOUSE, LOOKING WEST. THE WIRES AND BEAM AT RIGHT OF PHOTOGRAPH HAVE BEEN ADDED TO STABILIZE TRUSS SYSTEM. - Saratoga Gas Light Company, Gasholder No. 2, Niagara Mohawk Power Corporation Substation Facility, intersection of Excelsior & East Avenues, Saratoga Springs, NY

  11. 8. 100 foot through truss underside of bridge, looking ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    8. 100 foot through truss - underside of bridge, looking north, showing the original concrete-filled cylinder pier, as well as the concrete, (extension), and 'I' beam additions used to raise the bridge level. This pier is the mid support for the two through trusses. - Weidemeyer Bridge, Spanning Thomes Creek at Rawson Road, Corning, Tehama County, CA

  12. DETAIL OF "FEET" OF MAIN TRUSS NORTH END. NOTE PLATES ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    DETAIL OF "FEET" OF MAIN TRUSS NORTH END. NOTE PLATES ON WHICH FEET REST ALLOWING EXPANSION OF TRUSS AS IT EXPANDS AND SHRINKS UNDER THE SUN - Missouri & North Arkansas Railroad Bridge, Spanning Middle Fork Little Red River, Shirley, Van Buren County, AR

  13. 17. 80 foot pony truss detail of the lower ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    17. 80 foot pony truss - detail of the lower pin connection located where an end post joins the first and the last vertical post. There are two pair on each of the five 80 foot trusses for a total of 20. - Weidemeyer Bridge, Spanning Thomes Creek at Rawson Road, Corning, Tehama County, CA

  14. 33 CFR 147.831 - Holstein Truss Spar safety zone.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Holstein Truss Spar safety zone. 147.831 Section 147.831 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OUTER CONTINENTAL SHELF ACTIVITIES SAFETY ZONES § 147.831 Holstein Truss Spar safety zone....

  15. 33 CFR 147.831 - Holstein Truss Spar safety zone.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Holstein Truss Spar safety zone. 147.831 Section 147.831 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OUTER CONTINENTAL SHELF ACTIVITIES SAFETY ZONES § 147.831 Holstein Truss Spar safety zone....

  16. 33 CFR 147.831 - Holstein Truss Spar safety zone.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Holstein Truss Spar safety zone. 147.831 Section 147.831 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OUTER CONTINENTAL SHELF ACTIVITIES SAFETY ZONES § 147.831 Holstein Truss Spar safety zone....

  17. 33 CFR 147.831 - Holstein Truss Spar safety zone.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false Holstein Truss Spar safety zone. 147.831 Section 147.831 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OUTER CONTINENTAL SHELF ACTIVITIES SAFETY ZONES § 147.831 Holstein Truss Spar safety zone....

  18. 33 CFR 147.831 - Holstein Truss Spar safety zone.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Holstein Truss Spar safety zone. 147.831 Section 147.831 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OUTER CONTINENTAL SHELF ACTIVITIES SAFETY ZONES § 147.831 Holstein Truss Spar safety zone....

  19. New displacement-based methods for optimal truss topology design

    NASA Technical Reports Server (NTRS)

    Bendsoe, Martin P.; Ben-Tal, Aharon; Haftka, Raphael T.

    1991-01-01

    Two alternate methods for maximum stiffness truss topology design are presented. The ground structure approach is used, and the problem is formulated in terms of displacements and bar areas. This large, nonconvex optimization problem can be solved by a simultaneous analysis and design approach. Alternatively, an equivalent, unconstrained, and convex problem in the displacements only can be formulated, and this problem can be solved by a nonsmooth, steepest descent algorithm. In both methods, the explicit solving of the equilibrium equations and the assembly of the global stiffness matrix are circumvented. A large number of examples have been studied, showing the attractive features of topology design as well as exposing interesting features of optimal topologies.

  20. Passively Adaptive Inflatable Structure for the Shooting Star Experiment

    NASA Technical Reports Server (NTRS)

    Tinker, Michael L..

    1998-01-01

    An inflatable structural system is described for the Shooting Star Experiment that is a technology demonstrator flight for solar thermal propulsion. The inflatable structure is a pressurized assembly used in orbit to support a fresnel lens for focusing sunlight into a thermal storage engine. When the engine temperature reaches a preset level, the propellant is injected into the storage engine, absorbs heat from a heat exchanger, and is expanded through the nozzle to produce thrust. The inflatable structure is an adaptive system in that a regulator and relief valve are utilized to maintain pressure within design limits during the full range of orbital conditions. Further, the polyimide film material used for construction of the inflatable is highly nonlinear, with modulus varying as a function of frequency, temperature, and level of excitation. A series of tests is described for characterizing the structure in response to various operating conditions.

  1. A variable geometry truss manipulator for positioning large payloads

    SciTech Connect

    Stoughton, R.S.; Tucker, J.C.; Horner, C.G.

    1995-02-01

    A major thrust within the Department of Energy`s (DOE) Decontamination and Dismantling (D&D) Robotics program is the development of a Selective Equipment Removal System (SERS). SERS will consist of a mobile vehicle, a Dual-Arm Work Module (DAWM), and a deployment manipulator capable of extending the DAWM up to 6.096m (20) from the vehicle. The DAWM, built by RedZone Robotics, includes two Schilling Titan II manipulators, a unique five degree-of-freedom (DOF) module for positioning/orienting the two Schilling arms, and a massive steel backplane to maintain structural rigidity. Together with its payload, the DAWM weighs about 975 kg (2150 pounds). In order to accurately position the DAWM, the Pacific Northwest Laboratory (PNL) together with the National Aeronautics and Space Administration`s Langley Research Center (NASA LARC) are developing a deployment manipulator, which includes two double-octahedral Variable Geometry Truss (VGT) modules connected with a static truss section. The entire SERS system (Figure 1) will include the mobile vehicle, a 2-DOF base actuation system (waist rotate and pitch) with an output link approximately 2.134m (7) in length, the VGT system and the DAWM. The VGT system (Figure 2) consists of a 1.067m (42) diameter ({approximately}1.346m (53) long) base VGT, which mounts to the end of the output link of the base actuation system, a 1.524m (60) long static truss section which tapers from 1.067m (42) diameter at its base to 0.8128m (32) diameter at the end, and a 0.8128m (32) diameter ({approximately}1.0922m (43) long) tip VGT to which the DAWM is mounted. The stiffness of the VGT system is such that with the base VGT mounted to a rigid base and the VGT system oriented horizontally (worst case), the static deflection of the DAWM together with full payload will be less than 0.0254m.

  2. Direct Adaptive Aircraft Control Using Dynamic Cell Structure Neural Networks

    NASA Technical Reports Server (NTRS)

    Jorgensen, Charles C.

    1997-01-01

    A Dynamic Cell Structure (DCS) Neural Network was developed which learns topology representing networks (TRNS) of F-15 aircraft aerodynamic stability and control derivatives. The network is integrated into a direct adaptive tracking controller. The combination produces a robust adaptive architecture capable of handling multiple accident and off- nominal flight scenarios. This paper describes the DCS network and modifications to the parameter estimation procedure. The work represents one step towards an integrated real-time reconfiguration control architecture for rapid prototyping of new aircraft designs. Performance was evaluated using three off-line benchmarks and on-line nonlinear Virtual Reality simulation. Flight control was evaluated under scenarios including differential stabilator lock, soft sensor failure, control and stability derivative variations, and air turbulence.

  3. An adaptive genetic algorithm for crystal structure prediction

    SciTech Connect

    Wu, Shunqing; Ji, Min; Wang, Cai-Zhuang; Nguyen, Manh Cuong; Zhao, Xin; Umemoto, K.; Wentzcovitch, R. M.; Ho, Kai-Ming

    2013-12-18

    We present a genetic algorithm (GA) for structural search that combines the speed of structure exploration by classical potentials with the accuracy of density functional theory (DFT) calculations in an adaptive and iterative way. This strategy increases the efficiency of the DFT-based GA by several orders of magnitude. This gain allows a considerable increase in the size and complexity of systems that can be studied by first principles. The performance of the method is illustrated by successful structure identifications of complex binary and ternary intermetallic compounds with 36 and 54 atoms per cell, respectively. The discovery of a multi-TPa Mg-silicate phase with unit cell containing up to 56 atoms is also reported. Such a phase is likely to be an essential component of terrestrial exoplanetary mantles.

  4. Self-Adaptive Stepsize Search Applied to Optimal Structural Design

    NASA Astrophysics Data System (ADS)

    Nolle, L.; Bland, J. A.

    Structural engineering often involves the design of space frames that are required to resist predefined external forces without exhibiting plastic deformation. The weight of the structure and hence the weight of its constituent members has to be as low as possible for economical reasons without violating any of the load constraints. Design spaces are usually vast and the computational costs for analyzing a single design are usually high. Therefore, not every possible design can be evaluated for real-world problems. In this work, a standard structural design problem, the 25-bar problem, has been solved using self-adaptive stepsize search (SASS), a relatively new search heuristic. This algorithm has only one control parameter and therefore overcomes the drawback of modern search heuristics, i.e. the need to first find a set of optimum control parameter settings for the problem at hand. In this work, SASS outperforms simulated-annealing, genetic algorithms, tabu search and ant colony optimization.

  5. Adaptivity and smart algorithms for fluid-structure interaction

    NASA Technical Reports Server (NTRS)

    Oden, J. Tinsley

    1990-01-01

    This paper reviews new approaches in CFD which have the potential for significantly increasing current capabilities of modeling complex flow phenomena and of treating difficult problems in fluid-structure interaction. These approaches are based on the notions of adaptive methods and smart algorithms, which use instantaneous measures of the quality and other features of the numerical flowfields as a basis for making changes in the structure of the computational grid and of algorithms designed to function on the grid. The application of these new techniques to several problem classes are addressed, including problems with moving boundaries, fluid-structure interaction in high-speed turbine flows, flow in domains with receding boundaries, and related problems.

  6. Controller-structure interaction compensation using adaptive residual mode filters

    NASA Technical Reports Server (NTRS)

    Davidson, Roger A.; Balas, Mark J.

    1990-01-01

    It is not feasible to construct controllers for large space structures or large scale systems (LSS's) which are of the same order as the structures. The complexity of the dynamics of these systems is such that full knowledge of its behavior cannot by processed by today's controller design methods. The controller for system performance of such a system is therefore based on a much smaller reduced-order model (ROM). Unfortunately, the interaction between the LSS and the ROM-based controller can produce instabilities in the closed-loop system due to the unmodeled dynamics of the LSS. Residual mode filters (RMF's) allow the systematic removal of these instabilities in a matter which does not require a redesign of the controller. In addition RMF's have a strong theoretical basis. As simple first- or second-order filters, the RMF CSI compensation technique is at once modular, simple and highly effective. RMF compensation requires knowledge of the dynamics of the system modes which resulted in the previous closed-loop instabilities (the residual modes), but this information is sometimes known imperfectly. An adaptive, self-tuning RMF design, which compensates for uncertainty in the frequency of the residual mode, has been simulated using continuous-time and discrete-time models of a flexible robot manipulator. Work has also been completed on the discrete-time experimental implementation on the Martin Marietta flexible robot manipulator experiment. This paper will present the results of that work on adaptive, self-tuning RMF's, and will clearly show the advantage of this adaptive compensation technique for controller-structure interaction (CSI) instabilities in actively-controlled LSS's.

  7. Rapid Structured Volume Grid Smoothing and Adaption Technique

    NASA Technical Reports Server (NTRS)

    Alter, Stephen J.

    2006-01-01

    A rapid, structured volume grid smoothing and adaption technique, based on signal processing methods, was developed and applied to the Shuttle Orbiter at hypervelocity flight conditions in support of the Columbia Accident Investigation. Because of the fast pace of the investigation, computational aerothermodynamicists, applying hypersonic viscous flow solving computational fluid dynamic (CFD) codes, refined and enhanced a grid for an undamaged baseline vehicle to assess a variety of damage scenarios. Of the many methods available to modify a structured grid, most are time-consuming and require significant user interaction. By casting the grid data into different coordinate systems, specifically two computational coordinates with arclength as the third coordinate, signal processing methods are used for filtering the data [Taubin, CG v/29 1995]. Using a reverse transformation, the processed data are used to smooth the Cartesian coordinates of the structured grids. By coupling the signal processing method with existing grid operations within the Volume Grid Manipulator tool, problems related to grid smoothing are solved efficiently and with minimal user interaction. Examples of these smoothing operations are illustrated for reductions in grid stretching and volume grid adaptation. In each of these examples, other techniques existed at the time of the Columbia accident, but the incorporation of signal processing techniques reduced the time to perform the corrections by nearly 60%. This reduction in time to perform the corrections therefore enabled the assessment of approximately twice the number of damage scenarios than previously possible during the allocated investigation time.

  8. Rapid Structured Volume Grid Smoothing and Adaption Technique

    NASA Technical Reports Server (NTRS)

    Alter, Stephen J.

    2004-01-01

    A rapid, structured volume grid smoothing and adaption technique, based on signal processing methods, was developed and applied to the Shuttle Orbiter at hypervelocity flight conditions in support of the Columbia Accident Investigation. Because of the fast pace of the investigation, computational aerothermodynamicists, applying hypersonic viscous flow solving computational fluid dynamic (CFD) codes, refined and enhanced a grid for an undamaged baseline vehicle to assess a variety of damage scenarios. Of the many methods available to modify a structured grid, most are time-consuming and require significant user interaction. By casting the grid data into different coordinate systems, specifically two computational coordinates with arclength as the third coordinate, signal processing methods are used for filtering the data [Taubin, CG v/29 1995]. Using a reverse transformation, the processed data are used to smooth the Cartesian coordinates of the structured grids. By coupling the signal processing method with existing grid operations within the Volume Grid Manipulator tool, problems related to grid smoothing are solved efficiently and with minimal user interaction. Examples of these smoothing operations are illustrated for reduction in grid stretching and volume grid adaptation. In each of these examples, other techniques existed at the time of the Columbia accident, but the incorporation of signal processing techniques reduced the time to perform the corrections by nearly 60%. This reduction in time to perform the corrections therefore enabled the assessment of approximately twice the number of damage scenarios than previously possible during the allocated investigation time.

  9. Adaptive polyphase subband decomposition structures for image compression.

    PubMed

    Gerek, O N; Cetin, A E

    2000-01-01

    Subband decomposition techniques have been extensively used for data coding and analysis. In most filter banks, the goal is to obtain subsampled signals corresponding to different spectral regions of the original data. However, this approach leads to various artifacts in images having spatially varying characteristics, such as images containing text, subtitles, or sharp edges. In this paper, adaptive filter banks with perfect reconstruction property are presented for such images. The filters of the decomposition structure which can be either linear or nonlinear vary according to the nature of the signal. This leads to improved image compression ratios. Simulation examples are presented. PMID:18262904

  10. Space station structures development

    NASA Technical Reports Server (NTRS)

    Teller, V. B.

    1986-01-01

    A study of three interrelated tasks focusing on deployable Space Station truss structures is discussed. Task 1, the development of an alternate deployment system for linear truss, resulted in the preliminary design of an in-space reloadable linear motor deployer. Task 2, advanced composites deployable truss development, resulted in the testing and evaluation of composite materials for struts used in a deployable linear truss. Task 3, assembly of structures in space/erectable structures, resulted in the preliminary design of Space Station pressurized module support structures. An independent, redundant support system was developed for the common United States modules.

  11. Adaptive cellular structures and devices with internal features for enhanced structural performance

    NASA Astrophysics Data System (ADS)

    Pontecorvo, Michael Eugene

    This dissertation aims to develop a family of cellular and repeatable devices that exhibit a variety of force-displacement behaviors. It is envisioned that these cellular structures might be used either as stand-alone elements, or combined and repeated to create multiple types of structures (i.e. buildings, ship hulls, vehicle subfloors, etc.) with the ability to passively or actively perform multiple functions (harmonic energy dissipation, impact mitigation, modulus change) over a range of loading types, amplitudes, and frequencies. To accomplish this goal, this work combines repeatable structural frameworks, such as that provided by a hexagonal cellular structure, with internal structural elements such as springs, viscous dampers, buckling plates, bi-stable von Mises trusses (VMTs), and pneumatic artificial muscles (PAMs). The repeatable framework serves to position damping and load carrying elements throughout the structure, and the configuration of the internal elements allow each cell to be tuned to exhibit a desired force-displacement response. Therefore, gradient structures or structures with variable load paths can be created for an optimal global response to a range of loads. This dissertation focuses on the development of cellular structures for three functions: combined load-carrying capability with harmonic energy dissipation, impact mitigation, and cell modulus variation. One or more conceptual designs are presented for devices that can perform each of these functions, and both experimental measurements and simulations are used to gain a fundamental understanding of each device. Chapter 2 begins with a presentation of a VMT model that is the basis for many of the elements. The equations of motion for the VMT are derived and the static and dynamic behavior of the VMT are discussed in detail. Next, two metrics for the energy dissipation of the VMT - hysteresis loop area and loss factor - are presented. The responses of the VMT to harmonic displacement

  12. An adaptive identification and control scheme for large space structures

    NASA Technical Reports Server (NTRS)

    Carroll, J. V.

    1988-01-01

    A unified identification and control scheme capable of achieving space at form performance objectives under nominal or failure conditions is described. Preliminary results are also presented, showing that the methodology offers much promise for effective robust control of large space structures. The control method is a multivariable, adaptive, output predictive controller called Model Predictive Control (MPC). MPC uses a state space model and input reference trajectories of set or tracking points to adaptively generate optimum commands. For a fixed model, MPC processes commands with great efficiency, and is also highly robust. A key feature of MPC is its ability to control either nonminimum phase or open loop unstable systems. As an output controller, MPC does not explicitly require full state feedback, as do most multivariable (e.g., Linear Quadratic) methods. Its features are very useful in LSS operations, as they allow non-collocated actuators and sensors. The identification scheme is based on canonical variate analysis (CVA) of input and output data. The CVA technique is particularly suited for the measurement and identification of structural dynamic processes - that is, unsteady transient or dynamically interacting processes such as between aerodynamics and structural deformation - from short, noisy data. CVA is structured so that the identification can be done in real or near real time, using computationally stable algorithms. Modeling LSS dynamics in 1-g laboratories has always been a major impediment not only to understanding their behavior in orbit, but also to controlling it. In cases where the theoretical model is not confirmed, current methods provide few clues concerning additional dynamical relationships that are not included in the theoretical models. CVA needs no a priori model data, or structure; all statistically significant dynamical states are determined using natural, entropy-based methods. Heretofore, a major limitation in applying adaptive

  13. A Branch and Bound Approach for Truss Topology Design Problems with Valid Inequalities

    NASA Astrophysics Data System (ADS)

    Cerveira, Adelaide; Agra, Agostinho; Bastos, Fernando; Varum, Humberto

    2010-09-01

    One of the classical problems in the structural optimization field is the Truss Topology Design Problem (TTDP) which deals with the selection of optimal configuration for structural systems for applications in mechanical, civil, aerospace engineering, among others. In this paper we consider a TTDP where the goal is to find the stiffest truss, under a given load and with a bound on the total volume. The design variables are the cross-section areas of the truss bars that must be chosen from a given finite set. This results in a large-scale non-convex problem with discrete variables. This problem can be formulated as a Semidefinite Programming Problem (SDP problem) with binary variables. We propose a branch and bound algorithm to solve this problem. In this paper it is considered a binary formulation of the problem, to take advantage of its structure, which admits a Knapsack problem as subproblem. Thus, trying to improve the performance of the Branch and Bound, at each step, some valid inequalities for the Knapsack problem are included.

  14. A Branch and Bound Approach for Truss Topology Design Problems with Valid Inequalities

    SciTech Connect

    Cerveira, Adelaide; Agra, Agostinho; Bastos, Fernando; Varum, Humberto

    2010-09-30

    One of the classical problems in the structural optimization field is the Truss Topology Design Problem (TTDP) which deals with the selection of optimal configuration for structural systems for applications in mechanical, civil, aerospace engineering, among others. In this paper we consider a TTDP where the goal is to find the stiffest truss, under a given load and with a bound on the total volume. The design variables are the cross-section areas of the truss bars that must be chosen from a given finite set. This results in a large-scale non-convex problem with discrete variables. This problem can be formulated as a Semidefinite Programming Problem (SDP problem) with binary variables. We propose a branch and bound algorithm to solve this problem. In this paper it is considered a binary formulation of the problem, to take advantage of its structure, which admits a Knapsack problem as subproblem. Thus, trying to improve the performance of the Branch and Bound, at each step, some valid inequalities for the Knapsack problem are included.

  15. Modes of interconnected lattice trusses using continuum models, part 1

    NASA Technical Reports Server (NTRS)

    Balakrishnan, A. V.

    1991-01-01

    This represents a continuing systematic attempt to explore the use of continuum models--in contrast to the Finite Element Models currently universally in use--to develop feedback control laws for stability enhancement of structures, particularly large structures, for deployment in space. We shall show that for the control objective, continuum models do offer unique advantages. It must be admitted of course that developing continuum models for arbitrary structures is no easy task. In this paper we take advantage of the special nature of current Large Space Structures--typified by the NASA-LaRC Evolutionary Model which will be our main concern--which consists of interconnected orthogonal lattice trusses each with identical bays. Using an equivalent one-dimensional Timoshenko beam model, we develop an almost complete continuum model for the evolutionary structure. We do this in stages, beginning only with the main bus as flexible and then going on to make all the appendages also flexible-except for the antenna structure. Based on these models we proceed to develop formulas for mode frequencies and shapes. These are shown to be the roots of the determinant of a matrix of small dimension compared with mode calculations using Finite Element Models, even though the matrix involves transcendental functions. The formulas allow us to study asymptotic properties of the modes and how they evolve as we increase the number of bodies which are treated as flexible. The asymptotics, in fact, become simpler.

  16. Novel MRE/CFRP sandwich structures for adaptive vibration control

    NASA Astrophysics Data System (ADS)

    Kozlowska, J.; Boczkowska, A.; Czulak, A.; Przybyszewski, B.; Holeczek, K.; Stanik, R.; Gude, M.

    2016-03-01

    The aim of this work was the development of sandwich structures formed by embedding magnetorheological elastomers (MRE) between constrained layers of carbon fibre-reinforced plastic (CFRP) laminates. The MREs were obtained by mechanical stirring of a reactive mixture of substrates with carbonyl-iron particles, followed by orienting the particles into chains under an external magnetic field. Samples with particle volume fractions of 11.5% and 33% were examined. The CFRP/MRE sandwich structures were obtained by compressing MREs samples between two CFRP laminates composed. The used A.S.SET resin was in powder form and the curing process was carried out during pressing with MRE. The microstructure of the manufactured sandwich beams was inspected using SEM. Moreover, the rheological and damping properties of the examined materials with and without a magnetic field were experimentally investigated. In addition, the free vibration responses of the adaptive three-layered MR beams were studied at different fixed magnetic field levels. The free vibration tests revealed that an applied non-homogeneous magnetic field causes a shift in natural frequency values and a reduction in the vibration amplitudes of the CFRP/MRE adaptive beams. The reduction in vibration amplitude was attributed mainly to the stiffening effect of the MRE core and only a minor contribution was made by the enhanced damping capacity, which was evidenced by the variation in damping ratio values.

  17. Scale-adaptive surface modeling of vascular structures

    PubMed Central

    2010-01-01

    Background The effective geometric modeling of vascular structures is crucial for diagnosis, therapy planning and medical education. These applications require good balance with respect to surface smoothness, surface accuracy, triangle quality and surface size. Methods Our method first extracts the vascular boundary voxels from the segmentation result, and utilizes these voxels to build a three-dimensional (3D) point cloud whose normal vectors are estimated via covariance analysis. Then a 3D implicit indicator function is computed from the oriented 3D point cloud by solving a Poisson equation. Finally the vessel surface is generated by a proposed adaptive polygonization algorithm for explicit 3D visualization. Results Experiments carried out on several typical vascular structures demonstrate that the presented method yields both a smooth morphologically correct and a topologically preserved two-manifold surface, which is scale-adaptive to the local curvature of the surface. Furthermore, the presented method produces fewer and better-shaped triangles with satisfactory surface quality and accuracy. Conclusions Compared to other state-of-the-art approaches, our method reaches good balance in terms of smoothness, accuracy, triangle quality and surface size. The vessel surfaces produced by our method are suitable for applications such as computational fluid dynamics simulations and real-time virtual interventional surgery. PMID:21087525

  18. Algorithms and data structures for adaptive multigrid elliptic solvers

    NASA Technical Reports Server (NTRS)

    Vanrosendale, J.

    1983-01-01

    Adaptive refinement and the complicated data structures required to support it are discussed. These data structures must be carefully tuned, especially in three dimensions where the time and storage requirements of algorithms are crucial. Another major issue is grid generation. The options available seem to be curvilinear fitted grids, constructed on iterative graphics systems, and unfitted Cartesian grids, which can be constructed automatically. On several grounds, including storage requirements, the second option seems preferrable for the well behaved scalar elliptic problems considered here. A variety of techniques for treatment of boundary conditions on such grids are reviewed. A new approach, which may overcome some of the difficulties encountered with previous approaches, is also presented.

  19. Multivariable feedback active structural acoustic control using adaptive piezoelectric sensoriactuators.

    PubMed

    Vipperman, J S; Clark, R L

    1999-01-01

    An experimental implementation of a multivariable feedback active structural acoustic control system is demonstrated on a piezostructure plate with pinned boundary conditions. Four adaptive piezoelectric sensoriactuators provide an array of truly colocated actuator/sensor pairs to be used as control transducers. Radiation filters are developed based on the self- and mutual-radiation efficiencies of the structure and are included into the performance cost of an H2 control law which minimizes total radiated sound power. In the cost function, control effort is balanced with reductions in radiated sound power. A similarity transform which produces generalized velocity states that are required as inputs to the radiation filters is presented. Up to 15 dB of attenuation in radiated sound power was observed at the resonant frequencies of the piezostructure. PMID:9921654

  20. 3. Photographic copy of roof truss construction details for Building ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. Photographic copy of roof truss construction details for Building 4505, Taylor & Barnes, Architects & Engineers, 803 W. Third Street, Los Angeles California, O.C.E. Office of Civil Engineer Job No. A(9-10), Military Construction: Materiel Command Flight Test Base, Muroc, California, Hangar and Auxiliary Buildings: Hangar Type P-A, Detail of Trusses T-2, T-3, T-4, T-5 & T6, Sheet No. 9, March 1944. A similar drawing for truss T-l is included in project field notes. Reproduced from the holdings of the National Archives, Pacific Southwest Region - Edwards Air Force Base, North Base, Hangar, End of North Base Road, Boron, Kern County, CA

  1. STS-113 P1 Truss paylad in Payload Changeout Room

    NASA Technical Reports Server (NTRS)

    2002-01-01

    KENNEDY SPACE CENTER, FLA. - From the Payload Changeout Room on Launch Pad 39A, the P1 truss payload, plus the Crew and Equipment Translation Aid (CETA) cart B, are moved into the payload bay of Space Shuttle Endeavour. Scheduled to launch Nov. 10 on mission STS-113, Endeavour will make the 16th assembly flight to the International Space Station. Once delivered, the P1 truss will remain stowed until flight 12A.1 in 2003 when it will be attached to the central truss segment, S0, on the Space Station. The mission will also deliver the Expedition 6 crew to the Station and return Expedition 5 to Earth.

  2. Heavily loaded joints for assembling aerobrake support trusses

    NASA Technical Reports Server (NTRS)

    Bandel, Hannskarl; Olsson, Nils; Levintov, Boris

    1990-01-01

    The major emphasis was to develop erectable joints for large aerobrake support trusses. The truss joints must be able to withstand the large forces experienced by the truss during the aero-pass, as well as be easily assembled and disassembled on orbit by astronauts or robots. Other important design considerations include; strength, stiffness, and allowable error in strut length. Six mechanical joint designs, as well as a seventh joint design, where a high strength epoxy is injected to make the connection rigid, are presented.

  3. Closeup view of portion of swingspan truss showing members and ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Close-up view of portion of swing-span truss showing members and their pin connections at joints. The vertical member (hanger) shown is a portion of a small secondary truss added in each subdivided panel to help support the bottom chord. The track timber ties span the distance (16'-0') center to center of trusses, rest on the bottom chord and support the track. Note: Several of the members shown are eyebars. - Bridgeport Swing Span Bridge, Spanning Tennessee River, Bridgeport, Jackson County, AL

  4. Section NN, showing steel roof trusses, mezzanine iron railing, first ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Section NN, showing steel roof trusses, mezzanine iron railing, first floor doors, etc. San Bernardino Valley Union Junior College, Library Building. Also includes steel truss roof plan and a small stress diagram of the truss. Howard E. Jones, Architect, San Bernardino, California. Sheet 8, job no. 315. Scales 1/2 inch to the foot (section), and 1/8 and 1/16 inch to the foot. No date given on sheet (probably March or April, 1927). - San Bernardino Valley College, Library, 701 South Mount Vernon Avenue, San Bernardino, San Bernardino County, CA

  5. Kinematic modeling of a double octahedral Variable Geometry Truss (VGT) as an extensible gimbal

    NASA Technical Reports Server (NTRS)

    Williams, Robert L., II

    1994-01-01

    This paper presents the complete forward and inverse kinematics solutions for control of the three degree-of-freedom (DOF) double octahedral variable geometry truss (VGT) module as an extensible gimbal. A VGT is a truss structure partially comprised of linearly actuated members. A VGT can be used as joints in a large, lightweight, high load-bearing manipulator for earth- and space-based remote operations, plus industrial applications. The results have been used to control the NASA VGT hardware as an extensible gimbal, demonstrating the capability of this device to be a joint in a VGT-based manipulator. This work is an integral part of a VGT-based manipulator design, simulation, and control tool.

  6. Design, realization and structural testing of a compliant adaptable wing

    NASA Astrophysics Data System (ADS)

    Molinari, G.; Quack, M.; Arrieta, A. F.; Morari, M.; Ermanni, P.

    2015-10-01

    This paper presents the design, optimization, realization and testing of a novel wing morphing concept, based on distributed compliance structures, and actuated by piezoelectric elements. The adaptive wing features ribs with a selectively compliant inner structure, numerically optimized to achieve aerodynamically efficient shape changes while simultaneously withstanding aeroelastic loads. The static and dynamic aeroelastic behavior of the wing, and the effect of activating the actuators, is assessed by means of coupled 3D aerodynamic and structural simulations. To demonstrate the capabilities of the proposed morphing concept and optimization procedure, the wings of a model airplane are designed and manufactured according to the presented approach. The goal is to replace conventional ailerons, thus to achieve controllability in roll purely by morphing. The mechanical properties of the manufactured components are characterized experimentally, and used to create a refined and correlated finite element model. The overall stiffness, strength, and actuation capabilities are experimentally tested and successfully compared with the numerical prediction. To counteract the nonlinear hysteretic behavior of the piezoelectric actuators, a closed-loop controller is implemented, and its capability of accurately achieving the desired shape adaptation is evaluated experimentally. Using the correlated finite element model, the aeroelastic behavior of the manufactured wing is simulated, showing that the morphing concept can provide sufficient roll authority to allow controllability of the flight. The additional degrees of freedom offered by morphing can be also used to vary the plane lift coefficient, similarly to conventional flaps. The efficiency improvements offered by this technique are evaluated numerically, and compared to the performance of a rigid wing.

  7. Thermal-distortion analysis of a spacecraft box truss in geostationary orbit

    NASA Technical Reports Server (NTRS)

    Cosgrove, Patrick A.; Farmer, Jeffery T.; Rowell, Lawrence F.

    1990-01-01

    The Mission to Planet Earth enlists the use of a geostationary platform to support Earth science monitoring instruments. The strongback for a proposed geostationary platform is a deployable box truss that supports two large diameter passive microwave radiometer (PMR) and several other science instruments. A study was performed to estimate the north-south and east-west pointing errors at the mounting locations of the two PMRs due to on-orbit thermal distortions of the main truss. The baseline configuration indicated that the east-west pointing error greatly exceeded the required limits. Primary origins of the pointing errors were identified, and methods for their reduction were discussed. Thermal performance enhancements to the truss structure were modeled and analyzed, including state-of-the-art surface coatings and insulation techniques. Comparisons of the thermal enhancements to the baseline were performed. Results demonstrated that using a thermal enclosure insulating technique reduced external heat fluxes, and distributed those heat fluxes more evenly throughout the structure, sufficiently reducing the pointing error to satisfy pointing accuracy requirements for the PMR's.

  8. Materials for adaptive structural acoustic control, volume 2

    NASA Astrophysics Data System (ADS)

    Cross, L. E.

    1993-04-01

    This report documents work carried out in the Materials Research Laboratory of the Pennsylvania State University over the first year of a new ONR sponsored University Research Initiative (URI) entitled Materials for Adaptive Structural Acoustic Control. For this report the activities have been grouped under the following topic headings: (1) General Summary Papers; (2) Materials Studies; (3) Composite Sensors; (4) Actuator Studies; (5) Integration Issues; (6) Processing Studies; (7) Thin Film Ferroelectrics. In material studies important advances have been made in the understanding of the evaluation of relaxor behavior in the PLZT's and of the order disorder behavior in lead scandium tantalate:lead titanate solid solutions and of the Morphotropic Phase Boundary in this system. For both composite sensors and actuators we have continued to explore and exploit the remarkable versatility of the flextensional moonie type structure. Finite element (FEA) calculations have given a clear picture of the lower order resonant modes and permitted the evaluation of various end cap metals, cap geometries and load conditions. In actuator studies multilayer structures have been combined with flextensional moonie endcaps to yield high displacement (50 micrometers) compact structures. Electrically controlled shape memory has been demonstrated in lead zirconate stannate titanate compositions, and used for controlling a simple latching relay.

  9. Materials for adaptive structural acoustic control, volume 3

    NASA Astrophysics Data System (ADS)

    Cross, L. E.

    1993-04-01

    This report documents work carried out in the Materials Research Laboratory of the Pennsylvania State University over the first year of a new ONR sponsored University Research Initiative (URI) entitled Materials for Adaptive Structural Acoustic Control. For this report the activities have been grouped under the following topic headings: (1) General Summary Papers; (2) Materials Studies; (3) Composite Sensors; (4) Actuator Studies; (5) Integration Issues; (6) Processing Studies; and (7) Thin Film Ferroelectrics. In material studies important advances have been made in the understanding of the evaluation of relaxor behavior in the PLZT's and of the order-disorder behavior in lead scandium tantalate:lead titanate solid solutions and of the Morphotropic Phase Boundary in this system. For both composite sensors and actuators, we have continued to explore and exploit the remarkable versatility of the flextensional moonie type structure. Finite element (FEA) calculations have given a clear picture of the lower order resonant modes and permitted the evaluation of various end cap metals, cap geometries, and load conditions. In actuator studies multilayer structures have been combined with flextensional moonie endcaps to yield high displacement (50 micrometers) compact structures. Electrically controlled shape memory has been demonstrated in lead zirconate stannate titanate compositions, and used for controlling a simple latching relay.

  10. Augmented mandibular bone structurally adapts to functional loading.

    PubMed

    Verhoeven, J W; Ruijter, J M; Koole, R; de Putter, C; Terlou, M; Cune, M S

    2013-12-01

    Long-term changes in trabecular bone structure during the 10 years following onlay grafting with simultaneous mandibular implant placement were studied. Extraoral radiographs of both mandibular sides in eight patients were taken regularly. Bone structure was analysed using a custom-written image analysis program. Parameters studied were trabecular area and perimeter and marrow cavity area and perimeter. After skeletonisation of the trabecular network, the number of end points and branching points, skeleton length, and branch angle were determined. The observed structural changes agree with the development of a more complex and more delicate or fine osseous structure. The bone shows more trabecular branching. All changes are most pronounced in the graft spongiosa, but are also found in the graft cortex and in the original mandible. The mean trabecular branch angle becomes more horizontal. The applied technique can be used to analyse long-term changes in the architecture of bone grafts. Changes found in the graft architecture correspond to changes expected after functional adaptation to loading. PMID:23791249

  11. Precise Truss Assembly Using Commodity Parts and Low Precision Welding

    NASA Technical Reports Server (NTRS)

    Komendera, Erik; Reishus, Dustin; Dorsey, John T.; Doggett, W. R.; Correll, Nikolaus

    2014-01-01

    Hardware and software design and system integration for an intelligent precision jigging robot (IPJR), which allows high precision assembly using commodity parts and low-precision bonding, is described. Preliminary 2D experiments that are motivated by the problem of assembling space telescope optical benches and very large manipulators on orbit using inexpensive, stock hardware and low-precision welding are also described. An IPJR is a robot that acts as the precise "jigging", holding parts of a local structure assembly site in place, while an external low precision assembly agent cuts and welds members. The prototype presented in this paper allows an assembly agent (for this prototype, a human using only low precision tools), to assemble a 2D truss made of wooden dowels to a precision on the order of millimeters over a span on the order of meters. The analysis of the assembly error and the results of building a square structure and a ring structure are discussed. Options for future work, to extend the IPJR paradigm to building in 3D structures at micron precision are also summarized.

  12. 10. Detail of truss located on top the northeast pier, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    10. Detail of truss located on top the northeast pier, looking southwest. - Bridge No. 4800, Spanning Minnesota River on Trunk Highway 4 between Brown & Nicollet Counties, Sleepy Eye, Brown County, MN

  13. 9. Detail of truss work on southwesternmost span, looking northnortheast ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    9. Detail of truss work on southwesternmost span, looking north-northeast - Bridge No. 4800, Spanning Minnesota River on Trunk Highway 4 between Brown & Nicollet Counties, Sleepy Eye, Brown County, MN

  14. Interior view of north wall showing roof trusses & monitor; ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Interior view of north wall showing roof trusses & monitor; camera facing northeast. - Mare Island Naval Shipyard, Smithery, California Avenue, west side at California Avenue & Eighth Street, Vallejo, Solano County, CA

  15. Facility No. 175, interior detail showing rolling doors, trusses, and ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Facility No. 175, interior detail showing rolling doors, trusses, and angled monitor roof - U.S. Naval Base, Pearl Harbor, Landplane Hangar Type, Wasp Boulevard and Gambier Bay Street, Pearl City, Honolulu County, HI

  16. 42. DETAIL VIEW OF TRIPLED, HEAVY TIMBER TRUSSES IN FOUNDRY. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    42. DETAIL VIEW OF TRIPLED, HEAVY TIMBER TRUSSES IN FOUNDRY. - Baltimore & Ohio Railroad, Mount Clare Shops, South side of Pratt Street between Carey & Poppleton Streets, Baltimore, Independent City, MD

  17. 41. DETAIL VIEW OF TRIPLED, HEAVY TIMBER TRUSSES IN FOUNDRY. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    41. DETAIL VIEW OF TRIPLED, HEAVY TIMBER TRUSSES IN FOUNDRY. - Baltimore & Ohio Railroad, Mount Clare Shops, South side of Pratt Street between Carey & Poppleton Streets, Baltimore, Independent City, MD

  18. 43. DETAIL VIEW OF TRIPLED, HEAVY TIMBER TRUSSES IN FOUNDRY. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    43. DETAIL VIEW OF TRIPLED, HEAVY TIMBER TRUSSES IN FOUNDRY. - Baltimore & Ohio Railroad, Mount Clare Shops, South side of Pratt Street between Carey & Poppleton Streets, Baltimore, Independent City, MD

  19. 14. BRIDGE ABUTMENT AND ARCH TRUSS MOUNTING PLATE SHOWING EYEBAR ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    14. BRIDGE ABUTMENT AND ARCH TRUSS MOUNTING PLATE SHOWING EYE-BAR CONNECTION AND EYE-BAR PIN LOCATION - Spruce Street Bridge, East Spruce Street, 500 Block, spanning Power Canal, Sault Ste. Marie, Chippewa County, MI

  20. DETAIL VIEW OF END OF TRUSS SHOWING CONNECTION OF DECORATIVE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    DETAIL VIEW OF END OF TRUSS SHOWING CONNECTION OF DECORATIVE "KNEE", RAILING ENDPOST AND UPPER AND LOWER CHORDS - Scarlets Mill Bridge, Spanning former Reading Railroad, Scarlets Mill, Berks County, PA

  1. 7. DETAIL VIEW SHOWING CONNECTION OF BRIDGE COLUMN, TRUSS, TOP ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    7. DETAIL VIEW SHOWING CONNECTION OF BRIDGE COLUMN, TRUSS, TOP BEAM, AND ARCHED CROSS MEMBER. NOTE KNEE BRACE FOR CROSS MEMBER AND DIAGONAL TENSION BAR - Heber Creeper Railroad Line, Olmstead Bridge, Spanning Provo River, Provo, Utah County, UT

  2. 14. View of swing truss apex with major sway bracing ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    14. View of swing truss apex with major sway bracing and bottom latticed strut members, with knee braces below. (Nov. 25, 1988) - University Heights Bridge, Spanning Harlem River at 207th Street & West Harlem Road, New York County, NY

  3. 11. OBLIQUE VIEW OF EAST TRUSS AND EAST SIDE OF ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    11. OBLIQUE VIEW OF EAST TRUSS AND EAST SIDE OF SOUTH ABUTMENT, SEEN FROM SOUTH BANK OF WINTER'S RUN. - Mitchell's Mill Bridge, Spanning Winter's Run on Carrs Mill Road, west of Bel Air, Bel Air, Harford County, MD

  4. 7. CLOSER OBLIQUE VIEW OF WEST TRUSS AND WEST SIDE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    7. CLOSER OBLIQUE VIEW OF WEST TRUSS AND WEST SIDE OF SOUTH ABUTMENT; VIEW TO NORTHEAST. - Mitchell's Mill Bridge, Spanning Winter's Run on Carrs Mill Road, west of Bel Air, Bel Air, Harford County, MD

  5. 15. SOUTH WEB AND WEST PORTAL OF MIDDLE THROUGH TRUSS. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    15. SOUTH WEB AND WEST PORTAL OF MIDDLE THROUGH TRUSS. VIEW TO NORTHEAST. - Abraham Lincoln Memorial Bridge, Spanning Missouri River on Highway 30 between Nebraska & Iowa, Blair, Washington County, NE

  6. 72. VIEW SHOWING THE ERECTION OF A TAINTER GATE TRUSS ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    72. VIEW SHOWING THE ERECTION OF A TAINTER GATE TRUSS ON TRUNNION PIN ON WEST SIDE OF BAY 9, LOOKING NORTHWEST. Taken on August 17, 1935. - Upper Mississippi River 9-Foot Channel, Lock & Dam No. 10, Guttenberg, Clayton County, IA

  7. 8. General view of truss geometry at center of span ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    8. General view of truss geometry at center of span from lower parking lot, looking northwest - Lower Rollstone Street Bridge, Spanning Nashua River on Rollstone Street, Fitchburg, Worcester County, MA

  8. 27. VIEW SOUTH; DETAIL OF TRUSSES IN AUDITORIUM. Naval ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    27. VIEW SOUTH; DETAIL OF TRUSSES IN AUDITORIUM. - Naval Undersea Warfare Center, Bowditch Hall, 600 feet east of Smith Street & 350 feet south of Columbia Cove, West bank of Thames River, New London, New London County, CT

  9. 6. OBLIQUE VIEW, FROM SOUTHWEST, SHOWING WEST PORTAL, THROUGH TRUSSES ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    6. OBLIQUE VIEW, FROM SOUTHWEST, SHOWING WEST PORTAL, THROUGH TRUSSES OF WEST SPAN, AND PORTION OF WEST APPROACH - Glendale Road Bridge, Spanning Deep Creek Lake on Glendale Road, McHenry, Garrett County, MD

  10. 6. West side, details of west truss web and floorbeam ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    6. West side, details of west truss web and floor-beam bracing by steel plates and steel rod; looking northeast - Bridge No. 92101, Spanning Pike River at County Highway 373, Embarrass, St. Louis County, MN

  11. View of movable span and point truss (to right), from ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View of movable span and point truss (to right), from navy land, looking west, showing bridge in context of navigational channel. - Naval Supply Annex Stockton, Daggett Road Bridge, Daggett Road traversing Burns Cut Off, Stockton, San Joaquin County, CA

  12. View of movable span and point truss (to right), from ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View of movable span and point truss (to right), from navy land, looking west, showing bridge in context of navigational channel. - Naval Supply Annex Stockton, Rough & Ready Island, Stockton, San Joaquin County, CA

  13. 19. DETAIL OF FLOORBEAM CONNECTION AT TRUSS PANEL POINT AND ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    19. DETAIL OF FLOORBEAM CONNECTION AT TRUSS PANEL POINT AND FLOOR STRINGER SUPPORT AT FLOORBEAMS - Wabash River Bridge, Spanning Wabash River over Salamonie Road (County Road 200 West), Huntington, Huntington County, IN

  14. 34. 100 foot through truss looking north from the ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    34. 100 foot through truss - looking north from the deck up to an internal top strut, showing the general configuration. - Weidemeyer Bridge, Spanning Thomes Creek at Rawson Road, Corning, Tehama County, CA

  15. 38. 100 foot through truss bridge original identification plaque ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    38. 100 foot through truss - bridge original identification plaque located on the top of the north portal entrance. - Weidemeyer Bridge, Spanning Thomes Creek at Rawson Road, Corning, Tehama County, CA

  16. 19. WEST ANCHOR SPAN OF THROUGH TRUSS AND PIERS NO. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    19. WEST ANCHOR SPAN OF THROUGH TRUSS AND PIERS NO. 2 AND 3, FROM WEST RIVERBANK. VIEW TO NORTH. - MacArthur Bridge, Spanning Mississippi River on Highway 34 between IA & IL, Burlington, Des Moines County, IA

  17. 12. DETAIL OF THROUGH TRUSS SPANS AND PIERS NO. 3, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    12. DETAIL OF THROUGH TRUSS SPANS AND PIERS NO. 3, 4 AND 5, FROM WEST RIVERBANK. VIEW TO NORTHEAST. - MacArthur Bridge, Spanning Mississippi River on Highway 34 between IA & IL, Burlington, Des Moines County, IA

  18. 22. DOWNSTREAM DETAIL OF PIER NO. 3, TRUSS TOWER AND ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    22. DOWNSTREAM DETAIL OF PIER NO. 3, TRUSS TOWER AND CANTILEVER ARMS. VIEW TO NORTHEAST. - MacArthur Bridge, Spanning Mississippi River on Highway 34 between IA & IL, Burlington, Des Moines County, IA

  19. 18. WEST DECK TRUSS APPROACH SPAN AND PIERS NO. 1 ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    18. WEST DECK TRUSS APPROACH SPAN AND PIERS NO. 1 AND 2, FROM WEST RIVERBANK. VIEW TO NORTHEAST. - MacArthur Bridge, Spanning Mississippi River on Highway 34 between IA & IL, Burlington, Des Moines County, IA

  20. Detail east panel of east truss showing rollling panels and ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Detail east panel of east truss showing rollling panels and counter weights. View south - New York, New Haven & Hartford Railroad, Fort Point Channel Rolling Lift Bridge, Spanning Fort Point Channel, Boston, Suffolk County, MA