Nonlinear Analysis of Pin-Jointed Space Trusses

A method of solution for nonlinear problems of space trusses is presented based on a general approach for solving nonlinear problems in structural mechanics as formulated by B. Budiansky. The method leads to exact equilibrium equations valid for arbitrarily large strains and deformations and written using the known initial geometry of the structure. The strain-displacement relations used are exact and the stress-strain relations are approximated by polynomials. The equilibrium equations obtained are polynomials in the unknown displacements of the joints. The theory includes the effects of prestress and temperature changes. A computer program was developed using the Newton-Raphson technique for the solution of the nonlinear equations. The program can be used efficiently for the analysis and design of reticulated shells and suspended structures. Two particular examples are presented and the solutions compared with those obtained by existing approximate methods.