Different material models for intra-ply shear and double-dome FE forming analysis

摘要

With the focus on fast and cost-efficient production methods, e.g. for lightweight automotive parts, fibre-reinforced thermoplastics are becoming more important compared to reinforced thermosets. After heating over their melting temperature, these materials are formable several times and can be processed using known stamping methods with suitable modifications. This makes it possible to use semifinished products in the form of pre-consolidated sheets. Forming simulations of fibre-reinforced thermoplastics (FRTs) are helpful to understand and modify the forming process. To reach accurate results, the determination of specific material parameters is required to describe the tensile, shear and bending stiffness as well as the friction behaviour (tool-ply and ply-ply) at the forming temperature of FRTs. The testing methods described in the literature by several authors are often deduced from methods used for dry textiles. Thus, the methods need to be adapted for the characterization of impregnated textiles. Shear stiffness is often identified by picture-frame tests or bias-extension tests. But there are no standardized methods for the temperature-dependent characterization of FRTs and the implementation of the characteristic values into a finite element (FE) model.