Structural scale decomposition of energy release rates for delamination propagation

A kinematic based decomposition of energy release rates for structural scale delamination propagation is established for a general class of 1-D propagation in both curved and flat composite structures. The energy release rates, and the associated decomposition, allow for geometric nonlinearities, are self consistent, and are compatible with typical thin structure models employed in the analysis of composite structures. The energy release rates are expressed explicitly in terms of the curvatures and membrane strains (forces) of the sublaminates at the delamination edge, are independent of the particular loading of the structure, and allow for simple computation, application, evaluation and comparison of the critical delamination energy (toughness) based on simple experiments. The decomposition established herein is applied to several limiting cases to check proper convergence and is then applied to several selected examples.