Structural Analysis of a Kinetic Energy Projectile During Launch

摘要

This paper presents the results of a three phase effort to quantify the structural integrity of a long rod kinetic energy penetrator projectile during launch. The first phase used the finite element method to investigate the two body problem of penetrator and sabot during peak launch loads. This portion of the analysis considered the effect of pressure loading, body forces, and different moduli to determine an estimate of the stresses present in the penetrator and sabot - particularly along the intersection between the two. These stresses were then used to determine the load transfer between the penetrator and sabot. The second phase of the effort applied the load transfer from phase one to a detailed finite element model of the thread-like lugs of the penetrator in order to determine the stress concentrations in the notch root area between the lugs. This portion of the work took into account the geometry, material properties, and load transfer of the lugs. The resulting stresses due to the shearing and bending loads and contact friction were analyzed to determine the location and magnitude of the largest tensile stresses at the surface of the lug root. The value of maximum tensile stress in the root of the penetrator lugs was then used in a fracture mechanics analysis to determine a critical flow size which would cause brittle fracture. Using fracture toughness measurements from depleted uranium penetrator materials, critical flaw sizes were calculated and used to determine the likelihood of failure during launch and to formulate NDT inspection standards. (Author)