Towards Integrative Simulation of Fatigue Loadings for Short Glass Fibers Reinforced Polyamide

Short glass fiber reinforced polyamides (SFRPs) are a choice material for automotive industry, especially for in the engine compartment. To develop their application field to more and more complex hydrothermal and mechanical environments, reliable or even predictive simulation technologies are necessary. Integrative simulation takes into account the forming process during final Finite Elements Analysis (FEA). For SFRPs, injection molding is taken into account by computing glass fibers orientation. It is further used to compute a specific anisotropic constitutive model on each integration point of FEA model. A wide variety of models is now available. Integrative simulation using Digimat has been proved very efficient for static and dynamic loadings. Its use for fatigue loadings is still under development in the frame of a consortium uniting Digimat Software editor, Solvay a major polyamide supplier, car makers (Toyota and PSA), tier one suppliers (TBVC and SOGEFI), and some European academic labs. Work led in the consortium has included upstream material studies aimed at SFRPS fatigue behavior modeling, algorithm development and CAE chain optimization. A big effort has also been made in order to model moisture sorption of polyamide parts in service conditions under the hood. The project has brought to correlations between parts tests and FEA case studies. Results obtained show satisfying correlations between actual behavior and predicted fatigue resistance. Work goes on to improve correlations and industrialize this new fatigue simulation technology.