Influence of crack wake mechanisms on the dynamic fracture of multiply delaminated plates

The paper deals with the dynamic interaction of multiple delaminations in composite plates subject to out of plane loading. In order to develop a basic understanding of the problem, the work refers to the model system of a multiply delaminated plate deforming in cylindrical bending. Interaction effects on fracture parameters, dynamic crack growth, energy absorption and damage and impact tolerance are investigated. Large scale crack bridging mechanisms, such as those produced by a through-thickness reinforcement, strongly control and regularize the dynamic response of systems of stationary delaminations. In the free vibration phase that follows the removal of the load, the crack bridging action developed by a typical through-thickness reinforcement prevents out of phase vibrations and hammering of the delaminated layers and limits amplification of the fracture parameter