Material Model for the Compression Behavior in SMC

The aim of the project is the development of an efficient and accurate material model for the prediction of the flow behavior and the fiber orientation in SMC materials.

Sheet Molding Compound (SMC) is a long fiber reinforced thermoset prepreg material, which is processed into a finished component by compression molding. The mechanical properties of SMC components are strongly dependent on process-induced properties such as fiber orientation and distribution, flow front development, weld lines and air pores. To predict the component properties, a process simulation of SMC compression molding is carried out in the commercial finite element code LS-DYNA®.

The main goal of this project is the development of an accurate material model describing the flow behavior and resulting fiber orientation of compressible SMC materials. Starting from a model using the Folgar-Tucker description of the fiber orientation and fiber interaction effects developed for short fiber reinforced materials; a user-defined material model is constructed in the commercial finite element code LS-DYNA. With multi-physics solvers and the necessary tools for creating user-defined material models, most of the necessary factors and effects can be taken into account. Due to the high fiber volume content and long fiber lengths in SMC materials, the description of the flow behavior is based on a solid mechanics formulation.