A simulation for ductile fracture prediction of crystalline polymer based on craze behaviour (A model for propagation and growth cessation of craze and analysis with a commercial FEM solver)

Ductile fracture of crystalline polymer is caused by accumulation of craze that is one of damage peculiar to polymer. A simulation for fracture prediction based on the fracture mechanism of polymer is recently recognized as one of the most important industrial themes. In this paper, the craze evolution equation that can express propagation and growth cessation of craze, the evolution equation of mean normal plastic strain and the criterion for craze initiation with strain rate dependency are discussed and are proposed as a material model considering the craze effect by combining with non-coaxial elastoviscoplastic constitutive equation proposed in the previous paper. A three-dimensional FE simulation for a polypropylene plate under uni-axial tension is performed on a commercial FEM solver in which the above material model is installed through the user subroutine. Then, the validity of the present material model is shown by the accurate failure prediction based on craze accumulation.