Damage modeling of injection-molded short-and long- fiber thermoplastics

This article applies the recent anisotropic rotary diffusion - reduced strain closure (ARD- RSC) model for predicting fiber orientation and a new damage model for injection-molded long- fiber thermoplastics (LFTs) to analyze progressive damage leading to total failure of injection- molded long-glass-fiber/polypropylene (PP) specimens. The ARD-RSC model was implemented in a research version of the Autodesk Moldflow Plastics Insight (MPI) processing code, and it has been used to simulate injection-molding of a long-glass-fiber/PP plaque. The damage model combines micromechanical modeling with a continuum damage mechanics description to predict the nonlinear behavior due to plasticity coupled with damage in LFTs. This model has been implemented in the ABAQUS finite element code via user-subroutines and has been used in the damage analyses of tensile specimens removed from the injection-molded long-glass- fiber/PP plaques. Experimental characterization and mechanical testing were performed to provide input data to support and validate both process modeling and damage analyses. The predictions are in agreement with the experimental results.