Deformation and tearing of circular plates subjected to impulsive loads

Numerical solution for the transient dynamic finite element analysis methodology for circular plates under impulsive load time history is proposed for execution in FEA package ANSYS. Experimental results by Nurick et al. for the prediction of onset of thinning and subsequent tearing at the boundary of clamped circular plates subjected to uniformly loaded air blasts have been used to compare and validate the numerical simulation and procedure. The Mode II failure in respect of clamped circular plates has been simulated using a rupture strain criteria. Mode III failure of plastic shear sliding has been considered with a shear strain failure model as proposed by Wen et al. where in the circular plate parameters have been used. A stiffness reduction scheme has been proposed to decide on the initiation and progression of tearing in conjunction with suitable failure model under mode II and mode III failure. The evolution of deflections, plastic zones, rupture zones and failure modes under the blast loading conditions are found to be in very good correlation with the experimental results of Nurick et al. The validated numerical model has further been used to study the effect of plate thickness on the deformation and tearing response of the circular plates subjected to impulsive loads.