Modelo elastoplástico para materiales ortótropos

A general orthotropic model adequate for the analysis of complex anisotropic materials like masonry is presented. The model takes into account the differences between strength in the principal directions of anisotropy and how these differences vary with the type of process, i.e., tension, compression or any other combination of stress. In this way a general type of initial anisotropy can be defined. The model can also take into account the evolution of anisotropy during the elastoplastic process. The proposed model comes from a generalisation of classical isotropic theory of plasticity and assumes the existence of two spaces: a real anisotropic space and a fictitious isotropic space. The stress tensors in both spaces are related through a transformation tensor that takes into account the anisotropy and depends on the stress state. The problem is solved in the fictitious isotropic space. This allows to use well known yield functions developed for standard isotropic materials