Investigation of sensitive parameters in the structural simulation tool chain for fiber reinforced plastics in automotive electronic control units

In automotive electronic control units (ECU) the use of fiber reinforced plastics is widely spread. In contrast to the common utilization of these materials their influence on the reliability of electronic or interconnecting components on Printed Circuit Board (PCB) is not yet sufficiently accounted for in design decisions in early stages of the product development. Fiber reinforced plastic parts exhibit a strong anisotropic macroscopic material behavior. Their deformation under thermal and mechanical load cannot be correctly predicted by simulation if oversimplified material properties are applied. However, this deformation behavior can dominate the strain and stress induced in electronic or interconnecting components on PCB and hence their reliability over lifetime. By means of an integrative simulation approach the influence of the microscopic fiber orientation on the macroscopic behavior of plastic parts can be evaluated. In this paper a study of sensitive parameters of the integrative simulation and their influence on the simulation quality and accuracy is presented. For this purpose test specimen have been cut from an ECU cover which is made of reinforced polybutylene terephthalate with 30 wt% short glass fiber (PBT-GF30). Subsequently, uni-axial, quasi-static tensile tests as well as structural finite element (FE) simulations, comparable to the experiments and including the mapping of fiber orientation information from injection molding simulation were performed.