Boundary element analysis by linearized nonlinear elastic material models: an application to no-tension systems

Abstract

This paper deals with the analysis of nonlinear elastic systems discretized by boundary elements in the presence of piecewise-linear material models. The problem is solved in the context of the ‘holonomic’ theory (or ‘deformation’ theory) of plasticity, plane-stress conditions only are dealt with and the implications of linearizing the relevant yield surface is briefly discussed. Piecewise-linear yield surfaces coupled with linear hardening lead to a linear complementarity problem, for which a step-by-step solution procedure is proposed. The paper gives details about the algorithm implemented and discusses its application with reference to the boundary element method. To illustrate the problem with reference to simple but still real systems, masonry walls are considered and a no-tension material model is assumed. Numerical results are presented and compared with those provided by programs that follow different approaches, but use the same assumptions (a no-tension material model with nonlinear, reversible behaviour): namely, a boundary element code based on a conventional ‘initial stress’ procedure and a finite element package.