Efficient Characterization and Modelling of the Nonlinear Behaviour of LFT for Crash Simulations

Modeling the nonlinear material behaviour of long fiber reinforced thermoplastics(LFT) presents a challenging task since local inhomogeneities and nonlinear effects must betaken into account also on the microscale. We present a computational method with which we can predict the nonlinear material response of a composite material using only standard DMA measurements on the pure polymer matrix material. The material models considered include plasticity, damage, viscoelasticity, and visco-plasticity as described in [1]. These models can be combined similar to the model from [2] and extended to the composite by assigning linear elastic properties to the fibers. The mechanical response of the composite is computed using an FFT-based technique [3].The geometry of the composite, in particular t he fiber orientation, can be characterized using injection molding simulations or micro CT scans. We create virtual models of the composite using the algorithm of [4]. We show that with this method, the material behaviour of the composite can be predicted while the experimental complexity needed for the material characterization is low.