Response of long rods to moving lateral pressure pulse: numerical evaluation in DYNA3D

In this paper a convenient method to study the response of long rod projectiles subjected to a traversing lateral load pulse is presented. This problem mimics the lateral interaction of a yawed projectile with an oblique plate target. There are certain numerical difficulties in using Lagrangian wavecodes directly to compute the lateral penetration interaction behavior associated with erosion of elements, which leads to apparent numerical instabilities and large scale lateral surface erosion of the penetrator. It is known from experiments that for low yaw angles, lateral erosion is absent. In such cases, we show that the plate target can be replaced by a loading pulse, which moves relative to the rod at a speed completely determined from the geometry. In addition to avoiding problems associated with erosion algorithm, this method results in a tremendous reduction in computation time due to absence of the target grid. Using this method, rod deflection is successfully computed, and fracture locations are identified.