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Chen, Gun-Shing

Publications and source records attributed to Chen, Gun-Shing.

24 records · Page 2
All sourcesNASA NTRSDOE OSTI
NASA NTRS1991

On an adaptive truss manipulator space crane concept

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.

Chen, Gun-Shing↗
NASA NTRS1991

The Space Infrared Telescope Facility structural design requirements

An effort is currently being carried out by the Jet Propulsion Laboratory (JPL) to study mission feasibility and to define functional requirements for various subsystems of the Space Infrared Telescope Facility (SIRTF). As a major part of this effort, structural design requirements have been derived based on the stated mission objectives. Design concerns addressed by these requirements include the limits on mass and location of the center of gravity, launch stiffness and dynamic characteristics, design loads and analysis criteria, survivability of the TITAN IV/Centaur launch environment, thermal control for maintaining a near absolute-zero operating temperature, and helium cryogen volume and storage for a five-year mission. To illustrate how the structural design requirements can be met, a point design of the SIRTF flight hardware system was developed, modeled, and analyzed. A description of the key features of this point design, along with pertinent modeling and analysis results, are discussed in this Paper.

Macneal, Paul D.↗
NASA NTRS1990

Passive Damping Of Vibrations In Truss Structures

Damping enhanced by redistribution of shear strains in damping materials. Report describes theoretical and experimental investigations of passive damping of vibrations in truss structures. Interest in passive damping revived by proposals to construct large trusses in outer space. Focuses on use of viscoelastic materials to damp longitudinal vibrations in tubular members of such structures.

Chen, Gun-Shing↗
NASA NTRS1990

Adaptive structures - Test hardware and experimental results

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.

Wada, Ben K.↗
NASA NTRS1988

Passive damping for space truss structures

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.

Chen, Gun-Shing↗