Mixed-mode thermo elastic delamination fracture behavior of composite skin stiffener containing interface delamination

This paper presents the thermo-elastic effect on materials having anisotropic behavior and stresses developed due to residual temperature on interlaminar delamination fracture characteristics of composite skin stiffener. For the preexisting interlaminar delaminations subjected to uniaxial loading and three-point bending of three-dimensional coupled field thermo-elastic finite element analyses have been accomplished. The individual mode of strain energy release rate along the delamination front has been evaluated by modified crack-closure integral method based on the concept of mechanics of linear elastic fracture. Qualitative comparison has been illustrated for the individual modes of energy release rate along the delamination front of skin stiffener for both the loadings. The influence of coupled field thermo-elastic material anisotropy of the constituting laminae has been reasoned for the asymmetric variation of total strain energy release rate along delamination front. This was found to be significantly higher for the case of residual thermal stresses compared to mechanical loading.