Optimization of thermal curing cycle for a large epoxy model

Abstract

Heat generation in an exothermic reaction during the curing process and low thermal conductivity of the epoxy resin produces high peak temperature and temperature gradients which result in internal and residual stresses, especially in large epoxy samples. In this paper, an optimization algorithm was developed and applied to predict the thermal cure cycle to minimize the temperature peak and thermal gradients within the material of an industrial epoxy model during the curing process. An inverse analysis was used to obtain the new coefficients of Kamal's equations for the model. To validate and verify the developed model, temperature profiles for several points of the material in the model were obtained by numerical simulation and compared with the previously experimentally measured data. With validated curing simulation, the mentioned inverse analysis and optimization algorithm were utilized to find the thermal curing cycle with several isothermal holds and temperature ramps. The new objective reference was proposed for the first time and used to optimize the cure cycle, which subsequently produced the same temperature profiles for all points. The results showed that the obtained optimized thermal curing cycle was most effective to decrease the peak temperature as well as temperature gradients of the material.