Large Displacement Elastic Buckling of Space Structures

Abstract

A nonlinear stiffness matrix based computer program is used to investigate the stability of elastic space structures whose likely failure modes are determined by examining the tangent stiffness matrix of the structure near its collapse load. For a structure whose exact initial geometry is known, the actual behavior under any given load can be calculated. Where the imperfections are unknown, the initial geometry is altered by adding those combinations of small imperfections that will excite the likely failure modes. A separate analysis for each of these cases reveals the degree of imperfection‐sensitivity of the respective failure modes in the structure. Experiments were performed on three model structures and a large dome in which both bifurcation and limitpoint behavior were observed. Where the exact initial geometry was unknown, the addition of a suitable set of imperfections produced results in agreement with the experiments. In cases where the more significant real imperfections could be measured before the tests, good agreement was obtained between experiment and analysis.