Polymeric Materials For Finite Element Analysis : Material Modeling And Calibration Against Experimental Data For Injection-molded Short Fiber Composites

Sammanfattning

Short fiber–reinforced polymers such as polypropylene glass fiber are increasingly adopted in the automotive industry due to their lightweight and manufacturability. However, their injection molding induced anisotropy and heterogeneity make accurate mechanical modeling particularly challenging. This thesis investigates the development and calibration of finite-element based material models for polymeric materials, with a focus on tensile and fatigue behavior. An experimental program was conducted, comprising tensile and fatigue tests on both compact and foamed (Ku-Fizz) injection-molded specimens of polypropylene glass fiber. The material behavior was calibrated using mean-field homogenization techniques, while the skin-core effect was represented through layered orthotropic plies to account for through-thickness variations. The results demonstrate that accurate and computationally efficient material modeling of short fiber–reinforced polymers is feasible when experimental calibration data is statistically representative. The combination of skin-core modeling, and homogenization provides a reliable simulation framework. At the same time, the study highlights the need for broader fatigue test coverage to further enhance predictive capability and strengthen component-level confidence in simulation-driven design.