Enhancement of Multiscale Modeling Methodology for Short Fiber Filled Injection Molded Parts Subjected to Uniaxial and Biaxial Loadings

Abstract

To facilitate progressive failure structural simulation of short fiber filled injection molded parts, Autodesk has developed multiscale modeling methodology and software to seamlessly link the results of injection molding simulation with subsequent nonlinear multiscale structural response simulation. The key features of the methodology include: 1) Automated mapping of the predicted fiber orientation distribution onto the finite element mesh that will be used for the nonlinear structural response simulation, 2) Enhancement of the structural response simulation with a multiscale, progressive failure, constitutive model for short fiber filled plastic materials that accounts for plasticity and rupture of the matrix constituent material, resulting in a composite material that exhibits an anisotropic, nonlinear response, and 3) A robust, automated material characterization process that uses a minimal amount of simple tensile test data from the short fiber filled plastic material to fit the parameters of the multiscale, progressive failure, constitutive model. Recently, this multiscale modeling methodology has been improved to accurately capture the peak load for different load angles relative to the flow direction of the injection molded plaque in uniaxial experiments. To accurately resolve the uniaxial response at different load angles of short fiber filled injection molded parts, two different enhancements are required. First, the material characterization process must be enhanced to consider the actual predicted distribution of fiber orientation over the test specimens used for characterization. This enhancement is necessary because, the material stresses predicted by the model are sensitive to fiber orientation tensor which varies significantly through the thickness of the injection molded plaque. In addition, the basic multiscale material model must be enhanced by improving the failure criterion used to predict rupture of the short fiber plastic. Finally the improvements are compared against biaxial coupon results for different load ratios in tension.