Characterization and Finite Element Modeling for Thermoset Resin of Carbon Fiber Prepregs During Curing

Abstract In this study, an epoxy resin, YZ-05, designed specifically for carbon fiber reinforced polymer prepregs, was characterized and modeled. A degassing method for the highly viscous YZ-05 was established for specimen preparation. To numerically model the behavior of YZ-05 in curing, several components, including the heat transfer, curing kinetics, and viscoelastic constitutive law ones, were developed, and the corresponding material properties to be input were tested. As YZ-05 shows severe creep at high temperature under mechanical loading, the combination of digital image correlation (DIC) and thermography technique was utilized to obtain its thermal expansion and chemical shrinkage. In the aspects of viscoelastic behavior, stress relaxation tests were performed based on time–temperature superposition principle with a numerical method to calculate shift factors. After development and input identification, these modeling components for YZ-05 resin were integrated and the modeling results were validated using experiments, where bending of resin beams was induced during curing.