Multiscale modeling based failure criterion of injection molded SFRP composites considering skin-core-skin layered microstructure and variable parameters

Abstract

Injection molded short fiber reinforced polymer (IMSFRP) composites are superior lightweight materials with great potential application in many industries. One of the most challenging tasks is to predict the failure strength of the materials containing complicated fiber distributions. In this study, a parameterized failure criterion of IMSFRP composites is proposed based on multiscale modeling method. On the microscale, the RVE models with multiple constituents and different fiber orientation distributions are built to predict the failure envelopes of the microstructures. The constitutive model of single layer is proposed to describe micromechanical behaviors of the materials. On the mesoscale, a skin-core-skin (SCS) model is proposed considering the variation of fiber orientation in the thickness direction, namely layered structure. Three parameters of SCS model are extracted from the result of injection molding simulation and the relationships between the microstructural parameters and mechanical properties are built by means of surrogate modeling technique. Finally, a parameterized failure criterion is established which considers the layered structures of the materials and is capable to capture the variation of strength at different locations on a practical component. The numerical analysis and bench tests of an automobile IMSFRP composite liftgate inner verify the effectiveness and accuracy of the proposed parameterized failure criterion.