A generalized stress correction scheme for the MEB rheology: impact on the fracture angles and deformations

A generalized damage parameterization is developed for the Maxwell Elasto-Brittle (MEB) rheology that reduces the growth of residual errors associated with the correction of super-critical stresses. In the generalized stress correction, a decohesive stress tensor is used to bring the super-critical stresses back on the yield curve based on any correction path. The sensitivity of the simulated material behaviour to the magnitude of the decohesive stress tensor is investigated in uniaxial compression simulations. Results show that while the decohesive stress tensor influences the short-term fracture deformation and orientation, the long-term post-fracture behaviour remains unchanged. Divergence first occurs when the elastic response is dominant followed by post-fracture shear and convergence when the viscous response dominates – contrary to laboratory experiment of granular flow and satellite imagery in the Arctic. The post-fracture deformations are shown to be dissociated from the fracture process itself, an important difference with classical Viscous Plastic (VP) models. Using the generalized damage parameterization together with a stress correction path normal to the yield curve brings the simulated fracture angles closer to observations (from 40–50° to 35–45°, compared to 20–30° in observations) and reduces the growth of errors sufficiently for the production of longer-term simulations.