Computational performances optimization of a non-linear mechanical behaviour model for geomaterials

Abstract

Modelling large civil engineering structures with complex shapes, such as gothic vaults, arch dams, nuclear containment vessels, requires 3D nonlinear numerical models usable in finite element codes, discrete elements codes and codes coupling them both. Concerning the finite element formulation, many models based on plasticity are particularly well adapted to soil-mechanics, while damage theory is widely used to model concrete fracture. In the case of the building heritage masonry, in which natural geomaterials are combined with lime mortar, the mechanical behaviour law of the components presents a first stage with microcracking closure under low compression, a second stage of hardening, and finally a softening stage with a significant dilatancy and a damage induced by its crushing. In tension, the cracks appear mainly in principal tensile direction, with a highly orthotropic damage induced.  This paper gives principles used to couple all these phenomena in a single model with the objective to enhance the accuracy and minimize the computational cost. These improvements are based on a computing process avoiding to resort to iterative solving methods at the integration points.