Implementation and testing of methods for calculating the stress-strain state of elasto-plastic shells in CAE Fidesys

In paper the general formulation of solid mechanics boundary problems for elasto-plastic shells is presented. The approach to numerical modeling of shells in the MITC formulation on small strains in the context of the finite element method, which was implemented in the local strength analysis software CAE Fidesys, is considered. The development specific is to take into account the effects of plastic flow in the calculation of shells by implementing algorithms of integration over the thickness of the shell. Thus, it is possible to use the Huber-Mises yeld criterion directly in contrast to a number of studies, in which the condition for achieving plasticity is written in the resultants. The Newton-Raphson method was applied to solve nonlinear systems of equations. In paper the number of key aspects of the corresponding mathematical model is reviewed and presented. The algorithms implementation is evaluated by comparing the results obtained in the context of algorithms implementation in CAE Fidesys for elasto-plastic circular plate loading problems with similar results in other CAE programs. In particular, the problem which is appropriate to the Lame problem under plane-stress conditions and the plate bending problem are considered.