Adaptation of Walker-Anderson Model Elements into the Frank-Zook Penetration Model for Use in MUVES

摘要

The performance of the well-respected Frank-Zook (FZ) penetration algorithm is examined in light of an anticipated class of target technology involving laminated targets whose layers are thin relative to the projectile diameter (in the limiting case, this target class incorporates functionally graded materials). Because of the manner in which the FZ algorithm anticipates changes in material properties along the shotline of the penetrator, the algorithm is susceptible to inaccuracy precisely when the target layers along the shotline are thin relative to the projectile diameter. Though the problem can be quite severe when the target-layer thickness is a fraction of the projectile diameter, the effect is still evident to a much lesser extent, even as the target-element thickness is increased to several projectile diameters. A remedy to this type of problem is offered, accomplished by way of novel adaptation of elements of a model by Walker and Anderson into the FZ framework. In doing so, the target's material- and nonsteady-kinematic properties are dynamically composed via an integration through the plastic zone in the target, ahead of the rod/target interface. Additionally, a model to predict the crater- diameter profile resulting from a modeled penetration event is optionally offered as a calculation enhancement. The modeling remedies and enhancements proposed herein are offered for incorporation into the U.S. Army Research Laboratory's (ARL) modular Unix-based vulnerability estimation suite (MUVES) code, to be part of ARL's vulnerability/lethality (V/L) calculation methodology.