DAMAGE PROGRESSION IN LAMINATED AND SANDWICH STRUCTURES SUBJECTED TO DYNAMIC PULSE LOADS

The paper deals with the nonlinear response up to failure of flat and curved composite and sandwich structures subjected to blast loading. The post-elastic response of continuously supported sandwich beams subjected to dynamic pulse loads has been studied using a model that approximates the skin of the sandwich as a set of Timoshenko beams joined by cohesive interfaces and the core as a nonlinear Winkler foundation (Fig. 1a) [1,2]; the model is used to investigate the influence of the damage mechanisms for core crushing and skin delamination fracture on the response. Conclusions on the influence of geometrical and material properties and loading conditions on the mechanical response, final collapse and the transition between different failure modes will be drawn. Figure 1 shows an exemplary result that highlights the effects of the dynamic application of the load and core plasticity on the response of a sandwich beam with a skin delamination. In addition, preliminary results will be presented at the meeting on current mechanical modeling of the post-elastic response and collapse, caused by the initiation and propagation of delaminations, of laminated cylindrical shells subjected to blast loading. The work will complement recent solutions obtained for the failure modes for strength and geometric instability [3-5] to allow prediction of the final collapse.