A numerical investigation of penetration in multilayered material/structure systems

The response of multilayered ceramic/steel targets to high velocity impact and penetration has been investigated through finite element simulations. A multiple-plane microcracking model has been used to describe the inelastic constitutive behavior of ceramics in the presence of damage. The model has been integrated into the finite element code EPIC95, which possesses contact and erosion capabilities particularly suitable for ballistic simulations. The integrated code has been used to analyze the depth of penetration (DOP) and interface defeat (ID) ceramic target configurations. Parametric analyses have been carried out to establish the effect of ceramic materials, target configuration design for ceramic confinement, diameter/length ( d/L) ratio of the penetrator, material erosion threshold levels and the use of a shock attenuator on the response of multilayered targets subjected to high velocity impact. The response characteristics are established in terms of the parameters which can be measured experimentally. The analyses show that the integrated code is able to predict the response of ceramic targets in confirmation with experimental findings reported in the literature. The penetration process is found to be less dependent on the ceramic materials as usually assumed by most investigators. By contrast, the penetration process is highly dependent on the multilayered configuration and the target structural design (geometry, and boundary conditions). From a simulation standpoint, it has been found that the erosion parameter plays an important role in predicting the deformation history and interaction of the penetrator with the target. These findings show that meaningful lightweight armor design can only be accomplished through a combined experimental/numerical study in which relevant ballistic materials and structures are simultaneously investigated.