A methodology for measuring interface fracture properties of composite materials

A methodology is presented for measuring interface fracture properties of c omposite materials. A bimaterial Brazilian disk specimen with a crack along the interface is employed. The specimen is analyzed by means of the finite element method and a conservative integral to determine stress intensity f actors as a function of loading angle and crack length. A weight function i s employed to determine the effect of residual curing stresses on the stres s intensity factors. These are combined to determine the critical interface energy release rate g(ic) as a function of stress intensity phase angle Ps i for tests carried out on a glass/epoxy material pair.