Mixed discretization procedure for accurate modelling of plastic collapse

Abstract

Collapse loads are overestimated by finite‐element or finite‐difference procedures when the material discretization does not allow locally incompressible plastic flow: for example, constant‐strain triangles or tetrahedra give unacceptable results. The use of different discretizations for the isotropic and deviatoric parts of the strain tensor is advocated for preventing this problem. The technique can be easily implemented in existing two‐ and three‐dimensional computer programs. Its effectiveness is demonstrated by several examples.