Simulation On Crazing And Progressive Damage Of High Impact Polystyrenes

Crazing is typical damage phenomenon of polymer,The initiation, growth and breakdown of crazes in mesoscopic layer play a essential role in polymer's damage and ultimate fracture, which bridges the micromechanism of damage and macroscopic failure of polymers. It concerns not only the mechanism of plastic deformation and toughness but also the damage mechanism of polymers, which is an open problem for scientists of materials science and solid mechanics. Research have just been started to link the fundamental knowledge of micromechanics to the phenomenon of crazing of polymers,and this kind of studies have not yet played a key role in guiding the blend design.In the ABAQUS/CAE platform, based on micromechanics theory and method, 2D and 3D Representative Volume Element (RVE) damage numerical model are respectively presented to simulate the damage and failure of the crazing of High Impact Polystyrenes (HIPS).Firstly, a micromechanical model based on continuum mechanics is established to study the crazing of HIPS subjected to unidirectional tension by use of RVE with embedded cohesive surfaces. Quads failure criteria is adopted to identify the failure of cohesive elements. An elastic mechanical properties degradation method using the nonlinear finite element is introduced to simulate the initiation, growth and breakage of crazing. Furthermore, the crazing mechanisms are analyzed in details.Then, under the periodical boundary condition, a 3D RVE model is presented to simulate the damage and failure of the crazing of HIPS under unidirectional tension by using the nonlinear finite element method in the ABAQUS/CAE platform. Maximum principal stress criterion is considered for initial damage prediction of craze in matrix. The degradation of the mechanical properties is realized by reducing the stiffness of damage elements. Material mechanical properties are predicted from the calculated stress-strain curves.