Cure Simulation of Thermoset Composite Panels

Abstract

The curing of an open mold composite consisting of three laminated thermoset layers is simulated using a one-dimensional finite element model (FEM). This curing simulation addresses the reaction kinetics of each of the thermoset polyester resins as well as the thermal transport across the composite to calculate a time-dependent cure of each layer. Curing of each of the resins is modeled as an autocatalytic reaction based on the isothermal reaction exotherms at several temperatures. These reaction models depend sensitively on processing parameters. In particular, the models are specific to each polyester formulation, pre-promoter, and concentration of methyl ethyl ketone peroxide initiator. A nonlinear, transient, one-dimensional FEM coupling the reaction exotherm with the thermal properties of the composite is being implemented in Abaqus®. The measured temperature profiles of the composite layers during cure are semi-quantitatively reproduced by the model providing the degree of cure for each composite layer. Using the calculated degree of cure, the time evolution of the modulus of each layer can be estimated. While this simulation serves as a useful guide to the relationship between process parameters and laminate properties, it is not sufficiently accurate to provide process control for parameter optimization.