Abstract A series of dynamic tests were conducted on a closed-cell aluminum alloy foams in order to determine experimental failure surface under impact loading conditions. Quasi-static tests have also been performed to investigate failure mechanism under different stress paths. Three typical types of deformation modes can be observed, which corresponds to the different failure mechanism. The failure loci of the foam in principal stress plane are explored from quasi-static to dynamic loading conditions. A significant strength enhancement is identified experimentally. The expansion of the failure locus from the quasi-static to the dynamic test is almost isotropic. A modified failure criterion for the metallic foam is proposed to predict failure locus as a function of strain rate. This rate-dependence failure criterion is capable of giving a good description of the biaxial failure stresses over a wide range of the strain rates.

Abstract Finite element analysis was used to investigate the impact behavior of the foam-cored sandwich shells under the ballistic impact. The ballistic limit, failure mode of the face-sheet and energy absorption of the uniform/graded core were discussed in this paper. Based on the impact phase diagrams, the effects of several factors (i.e. projectile shape and diameter, face-sheet curvature and thickness) on the normal/oblique impact behavior were analyzed in detail. Results indicate that blunter and larger projectiles, higher impact velocity and thicker face-sheets can significantly raise the impact-resistance performance of the targets. In addition, the behavior of ballistic impact becomes more complex as the result of the increasing oblique angle.