A Novel Model for Predicting Deformation of Thermoplastic Composites During Thermoforming Process

Abstract

Carbon fiber/polyetheretherketone (CF/PEEK) thermoplastic composites are widely used in the aerospace industry due to their excellent mechanical properties and high-temperature resistance. However, the research on thermoforming deformation and residual stress during high-temperature and high-pressure thermoforming processes in CF/PEEK were relatively deficient. In this paper, a framework coupled of crystallization kinetics, micromechanics and thermodynamics was developed to predict the thermoforming deformations of CF/PEEK and it was conducted by UMAT, DISP and UEXPAN subroutines. Moreover, the predictive model was verified by experiments effectively. Finally, we compared the difference of residual stress distributions between symmetric and asymmetric lay-ups and found that the melting temperature, thickness, angle and sequence of layers have a significant impact on the thermoforming deformation. This work provided an effective tool for predicting thermoforming deformations, which is great of significance in the manufacturing and application of CF/PEEK.

Keywords: Thermoplastic composites, Thermoforming deformation, Residual stress, Finite element simulation