Linear and Nonlinear Stability Analysis of Trusses

This paper presents a comparison of critical loads for trusses, calculated by linear and nonlinear stability analysis. Analyses are provided by using finite elements method. In linear case, critical load is extracted from derived algebraic eigenvalue problem. In case of nonlinear analysis, critical load is determined by construction of postbuckling equilibrium path. Numerical examples for characteristics trusses are given. It is shown that in the case of some perfect trusses, linear approach may produce significant error in the calculation of critical load, and nonlinear analysis should be introduced. The conclusions about conditions for using linear and nonlinear approach to critical load calculation for trusses are derived.