Accession Number : ADA301635

Title :   Modeling of Joints for the Dynamic Analysis of Truss Structures.

Descriptive Note : Technical paper,

Corporate Author : NATIONAL AERONAUTICS AND SPACE ADMINISTRATION HAMPTON VA LANGLEY RESEARCH CEN TER

Personal Author(s) : Belvin, W. K.

PDF Url : ADA301635

Report Date : MAY 1987

Pagination or Media Count : 43

Abstract : A method for modeling joints to assess the influence of joints on the dynamic response of truss structures has been developed. The analytical models, which are based on experimental joint load-deflection behavior, use springs and dampers to simulate joint behavior. An algorithm for automatically computing nonlinear coefficients of the analytical models is also presented. The joint models are incorporated into a nonlinear finite-element program through use of special nonlinear spring, viscous, and friction elements. Next, the effects of nonlinear joint stiffness, such as dead band in the joint load-deflection behavior, are studied. Linearization of joint stiffness nonlinearities is performed to assess the accuracy of linear analysis in predicting nonlinear response. Viscous and friction damping are then used to show the effects of joint damping on global beam and truss structure response and equations for predicting the sensitivity of beam deformations to changes in joint stiffness are derived. In addition, the frequency sensitivity of a truss structure to random perturbations in joint stiffness is discussed and results are shown which indicate that average joint properties may be sufficient for predicting truss response.

Descriptors :   *SPACECRAFT, *TRUSSES, *JOINTS, MATHEMATICAL MODELS, ALGORITHMS, FINITE ELEMENT ANALYSIS, STRUCTURAL ANALYSIS, BEAMS(STRUCTURAL), DEFORMATION, DYNAMIC RESPONSE, STIFFNESS, DISPLACEMENT, MODULUS OF ELASTICITY, DAMPING, SENSITIVITY, STRUCTURAL RESPONSE, FRICTION, VISCOSITY, SPACE STATIONS, SPRINGS, CURVE FITTING.

Subject Categories : Unmanned Spacecraft
      Manned Spacecraft

Distribution Statement : APPROVED FOR PUBLIC RELEASE