Theoretical and Numerical Investigation on Perforation Resistance of Monolithic and Segmented Concrete Targets with Steel Liners under Normal Penetration

Steel-concrete composites are important armor protective materials with the increasing power of precision-guided weapons. In this study, the formula of residual velocity as well as the ratio between residual and initial kinetic energy (E-r/E-0) for concrete targets with a rear steel liner was derived. By establishing finite element models of steel liner concrete targets through ANSYS/LS-DYNA, the effect of the steel liner layout on the perforation resistance was analyzed for both monolithic and segmented concrete targets, which were compared in terms of projectile kinematics characteristics, projectile energy consumption, and target damages. Four main conclusions were drawn: (1) a residual velocity prediction model of concrete targets with a rear steel liner was accurately proposed for the first time when velocity reduction coefficient eta was 0.15 and the derived E-r/E-0 could be used to evaluate their corresponding perforation resistance; (2) moving back the steel liners enhanced the perforation resistance of both monolithic and segmented targets, but the performance of the latter was inferior to that of the former, which was reduced by 10%-16% under the same conditions; (3) during middle- and low-speed perforations, the projectile impact force was more influenced by the contact stiffness than the impact velocity; and (4) regarding the segmented targets, the perforation resistance of the 2nd target was better than the 1st target, which consumed about 10%-20% more projectile kinetic energy.