Residual Stress Effects in Fracture of Composites and Adhesives

Because composites and adhesive joints are made from different phases with different thermal expansion coefficients, they inevitably develop residual thermal stresses. When designing composites or adhesive joints, it is important to account for these residual stresses. It is not the magnitude of the residual stresses that matters, but rather the effect of those stresses on composite failure properties. This effect can be assessed by including residual stresses in fracture mechanics models of failure. This chapter gives general results for energy release rate in the presence of residual stresses. In many important problems, the effect of residual stress can be evaluated without any need for thermoelasticity analysis of the structure. Several examples of including residual stresses in fracture mechanics interpretation of experimental results are discussed.