Computational post failure analysis with Cosserat continuum

Abstract

We present computational analysis of geomechanics problems in the post failure regime based on a Cosserat material modelThe introduction of internal length (related to grain size) in the Cosserat model improves the computational stability and allows for robust progressive localization modelling. The model is capable of predicting advanced deformation modes such as surface buckling and localization of deformation in shear bands that may cause failure in a structure. The obtained results show clearly a progressive failure mechanism and the computed modes are in a good qualitative agreement with laboratory and field observations. As illustration we present results of two applications from petroleum engineering: the modelling of failure in thick walled cylinder test and the stability of elliptical shape perforations.