Modeling of Microcellular Short Fiber Reinforced Plastics for Pedestrian Safety Analysis

For efficient vehicle development there is a strive to reduce prototypes and shorten development times which leads to the need to rely on CAE methods for continuous evaluation of product performance. This puts demands on the CAE methods, not only in terms of predictability but also in terms of how well they integrate in the development process. Model preparation, material characterization and computational costs are important aspects for successful integration. New materials and production methods are other drivers for CAE method development as current methods may not be adequate. Short fiber reinforced polymers (SFRP) have found their way into more automotive applications in recent years. Weight, the geometrical possibilities, part production cycle times and cost are some of the potential benefits. The injection molding process, however, leads to an inhomogeneous distribution of fiber orientation throughout a part. As the fiber orientation distribution has significant impact on the mechanical properties it causes anisotropy and spatial variations of the material response. This paper addresses the modeling of an SFRP part which is produced by gas assisted injection molding leading to a porous, microcellular, material consisting of three phases, i.e. matrix-, fiber- and pore phases.