Modifications in EPIC-2 Subcycling and Quadrilaterals.

Abstract : The following modifications of the code EPIC-2 are described: (1) subcycling, which permits different time steps to be used in different parts of the mesh; (2) the addition of a four-node quadirlateral which uses one quadrature point and employs a consistent hourglass control and (3) a rigid interface to interconnect meshes with different element sizes. Both the theoretical and programming aspects are described. Keywords: Finite Elements; Impact; Ballistics.