Mechanical modeling of CF/PA6 sheet molding compounds with X-ray computed tomography-based internal geometry considerations

Abstract

In recent times, the application of sheet molding compounds (SMC) has been strongly restricted due to poor mechanical simulation results. These poor results occur because the complex internal geometry of SMCs makes it difficult to establish a precise simulation model. In the case of thermoplastic SMCs in particular, a high viscosity matrix and high molding pressure requirement lead to extreme fiber disturbance. This study utilizes the Mori-Tanaka (MT) model and the Equivalent Laminate (EL) model for the prediction of Young's modulus and the tensile strength of one CF/PA6 SMC, also referred to as CTT (chopped carbon fiber tape reinforced thermoplastics), with four different tape lengths. The complex internal geometries are measured using two X-ray computed tomography (CT) methods, with the quantified fiber orientation information input into the relevant models. The obtained simulation results were found to be in agreement with the experimental results. Within this study, the effect of the fiber length on Young's modulus and the tensile strength were investigated via the two models, and the advantages and disadvantages of both models are discussed.