ORTHOTROPIC YIELD CRITERIA IN A MATERIAL MODEL FOR TIMBER STRUCTURES

Abstract

The continuum structural model for the failure analysis of timber structures in the plane stress state is discussed in the paper. Constitutive relations are established in the framework of the mathematical multi-surface elasto-pla-sticity theory with three orthotropic strength criteria that have been incorporated in the model as the plasticity conditions. The invariant form of the criteria is given based on the representation theory of scalar-valued functions of the orthotropic invariants. The model is implemented into a commercial finite element code by means of user-defined subroutines. Introductory implementation tests of the proposed numerical algorithm are presented in the paper