Understanding residual stresses in thick polymer composite laminates

The process conditions of thick thermoset matrix composite laminates are complicated by adverse effects involving large out-of-plane temperature gradients and internal heat generation. This chapter introduces the method to analyse the transient heat transfer and the curing process of thick laminates, by combining the finite element method with thermo-chemical and self-consistent field micro-mechanical models. The methods of measurement of residual stresses in thick laminates are introduced. Some experimental results are demonstrated. The techniques discussed are applicable not only to the study of thermal residual stresses, but also stresses induced by environmentally induced internal stresses, such as caused by moisture, temperature gradient, solvents, etc.