Elastoplastic analysis of frames composed of softening materials by restricted basis linear programming

This paper is concerned with nonlinear analysis of frames composed of softening materials. The previously proposed dissipated energy maximization approach is extended to determine non-holonomic solution of such frames. The adopted assumptions are: linear kinematics, lumped plasticity with softening behavior, piecewise-linear yield functions, associate flow rule and isotropic evolution with a three phase linear softening rule. The approach is based on a mathematical programming formulation. The solution procedure is discussed and presented in a comprehensive flowchart. It is shown that this method has the ability of solving and tracing path dependent problems and detecting any possible bifurcation.