Efficient procedure for determining mixed-mode energy release rates in practical problems of delamination

A computationally efficient procedure is presented for the prediction of mixed-mode strain energy release rates in practical problems of delamination. In this procedure, an analytical crack tip element analysis is used for the determination of all singular field quantities. By comparison with two- and three-dimensional finite element results, the procedure is shown to be accurate for mixed-mode problems where mode I, mode II and/or mode III crack tip singularities are present. The procedure is applicable for those cases where a near-tip inverse-square-root singularity exists, as well as those where an oscillatory singularity exists. For these latter cases, an alternative approach to using oscillatory field quantities to characterize crack advance is suggested.