Numerical analysis of a phase field model for ductile fracture phenomena

In fracture mechanics, phase field theories have been introduced for the first time for brittle materials, in order to regularise the sharp crack topology. Especially, the crack surface part of the total energy functional is regularised by using a phase field variable. In the present work, a phase field model for ductile fracture in the framework of non-conventional thermodynamics is studied. In contrast to brittle fracture, the physical mechanisms for fracture are supposed to be driven by plastic deformation. The aim of the paper is to highlight, by analysing numerical examples, important features of the model that affect the predicted material responses. The analysis refers to assumptions commonly adopted in phase field theories and continuum damage mechanics and comprises the numerical robustness of the related finite element integrations. • Investigation of the influence of linear and quadratic degradation functions. • AT1/AT2 model assumptions lead to different crack propagation velocities. • Quadratic degradation functions are numerically more robust than linear ones.