Cure Simulation of Thick Thermosetting Composites

The potential for enhanced performance characteristics of composite materials over conventional metals, such as high strength-to-weight ratio, high stiffness, corrosion resistance and low radar signature, makes them extremely attractive for a wide range of military applications. The curing process of thick-section thermosetting composites is critical to the quality and in-service performance of the finished component. In this paper, an investigation into the two-dimensional cure simulation of thick thermosetting composites is presented. Temperature and degree of cure distributions within typical glasspolyester and graphiteepoxy structural elements of arbitrary cross-section ply-drop and angle bend are analyzed to provide insight into the non-uniform curing process unique to thick-sections. An incremental, transient finite difference solution scheme is implemented to solve the pertinent governing equations and boundary conditions. Correlation between experimentally measured and predicted through- the-thickness temperature profiles in glasspolyester laminates are presented for various arbitrary temperature cure cycle histories. Spatial gradients in degree of cure are shown to be strongly dependent on part geometry, thermal anisotropy, cure kinetics and the temperature cure cycle. These spatial gradients directly influence the quality and in-service performance of the finished component by inducing warpage and residual stress during the curing process. Keywords Thermoset composites Thick laminates Cure simulation Anisotropic heat conduction Boundary fitted coordinates Finite difference theory.