Simulating the onset of damage in DCDC tests using a novel gradient‐extended damage model for tension‐compression asymmetry

Abstract In the present work, an existing framework for gradient‐extended damage is extended to simulate the damage onset in double cleavage drilled compression (DCDC) tests. The main idea is to consider the different evolution of the damage variable under tensile and compressive loading. More specifically, the star‐convex decomposition is exploited to split the strain energy into an active part and an inactive part, and only the active part drives the evolution of the damage variable in the compressive regime. A parameter adopted in the star‐convex decomposition is applied to calibrate the compressive strength independently from the tensile strength, such that the current model can simulate different types of the damage onset. Furthermore, the strengthening effect induced by damage hardening is discussed in this work.