The heterogeneous and multi-phases modelization of composites for automotive lightweighting

Automotive design turns to composite materials especially because of their better ratio weight / mechanical strength. The use of these materials with various microstructural characteristics appears now on components submitted to severe mechanical loads for the respect of performances regarding to crash, endurance, and resistance to static load or vibro-acoustic requirements.
The simulation can be used to find the optimal design of these elements and then obtain why this composites are selected: lightweighting to reach objectives of worldwide regulations for CO2 emissions. The difficulty lies in the proper consideration of the influence of the manufacturing process on the geometry and on behaviour of the microstructure. For example, for the same choice of resin and fibers, an injection-molded reinforced plastic can have very different local behaviours depending on the injection parameters selected influencing local fiber orientations but also the characteristics of its constituents.
The presentation will show the importance of choosing a multi-phase material model to accurately simulate the nonlinear behavior of composites and their dependence on strain rate or temperature. Some application examples of this method on automotive industry cases will be presented to illustrate the concrete benefits that has already been obtained on the design of structural parts.