Underwater blast resistance of sacrificial claddings with small/significant strain hardening

Abstract

The vitality and fighting capacity of warships will be influenced by the underwater explosion–induced shock loadings. The foam materials have excellent energy dissipation capabilities and are widely used in mitigating impact/shock. In this article, a one-dimensional model for the shock mitigation of cellular claddings exhibiting small/significant strain hardening is proposed for both water blast loading and hydrostatic pressure. Special emphases are concentrated on the cellular material compression with actual stress–strain relationship and the effects of hydrostatic pressure on the shock mitigation performance of the cladding. Finite element models are developed to verify the analytical model. When considering the actual material relationship of the cellular claddings, the compaction mechanism is complex due to multiple reflections. A reflected secondary compression wave generates and propagates from the clamped end to the impinged end for a foam block with finite thickness. Later, there are even third or more compaction waves. It is worth to note that the part inside the secondary compacted zone continue to deform in quasi-static “Homogeneous” mode. Moreover, the effects of the hydrostatic pressure on the foam compression are revealed. The results can guide the design of such cellular claddings to water blast for naval ships.