A modified ductile fracture model incorporating synergistic effects of pressure and lode angle

A modified ductile fracture model is proposed based on continuum damage mechanics and three-stress-invariant criteria. In the modified model, the effects of hydrostatic pressure and Lode angle are considered and combined in the developed fracture envelope. To predict the fracture behaviors of ductile materials, the model is implemented into the commercial finite element platform ABAQUS/Explicit through a user material subroutine VUMAT. The validity of this model is examined by comparing the numerical results with experimental data of round bar and compact tension tests. It is demonstrated that comparing with other three-stress-invariant models the modified ductile fracture model can predict values compare favorably with experimental data especially in the unloading stage. The model can be adopted to predict the fracture patterns and unloading process of ductile materials and thus to investigate the whole range of the elastic-plastic ductile fracture behaviors of materials.