AN 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 del amination. In this procedure, an analytical crack tip element analysis is used for the determination of all singular field quantities. By co mparison with two- and three-dimensional finite element results, the p rocedure is shown to be accurate for mixed-mode problems where mode I, mode II and/or mode III crack tip singularities are present. The proc edure is applicable for those cases where a near-tip inverse-square-ro ot singularity exists, as well as those where an oscillatory singulari ty exists. For these latter cases, an alternative approach to using os cillatory field quantities to characterize crack advance is suggested.