Multi-scale finite element simulation of the thermoforming of a woven fabric glass fiber/polyetherimide thermoplastic composite

Understanding the thermoforming process for thermoplastic composites is of great importance to ensure the quality of the composite product but is difficult because of the complex material constitutive models and thermo-mechanical coupling in the thermoforming process. In this study, a woven fabric thermoplastic composite consisting of glass fiber and polyetherimide resin was thermoformed under one-sided cooling conditions. After the effective material properties are homogenized with newly developed, two-step asymptotic homogenization methods, and the temperature and pressure boundary conditions are measured experimentally, a 3D composite laminate sandwiched by interfacial layers and metal molds was finite element simulated in the macroscale. The simulated warpage, which was caused by the in-plane residual stresses, was consistent with the experimental results when reasonable tool-part interactions were considered. Subsequently, the temperature, displacement, strain, and stress were comprehensively discussed in terms of their spatial distribution, temporal evolution, and correlations with the others.