Experimental and numerical investigation on the shock resistance of honeycomb rubber coatings subjected to underwater explosion

A comparative study of honeycomb rubber coatings of the same material and total mass subjected to underwater explosion has been carried out in this article. Three types of cell topologies were considered: hexachiral honeycomb, reentrant honeycomb, and circular honeycomb. Three groups of live underwater explosion tests with different attack angles and stand-off distances were conducted on the stiffened metal boxes covered with the coatings. The free field water pressure and wall pressure near the coating's wet surface were monitored. The acceleration peaks at typical test locations on the inner structure were selected as the major comparative criterions. As a theoretical extension to the test work, finite element simulations have been undertaken using ABAQUS/Explicit software package to provide insights into the coating's working mechanism and the relation between compression behavior and water blast shock resistance. The results show that the protective effects of different coatings are consistent under different attack angles and stand-off distances. Compression performance depends on the coating structure and plays a dominant role in the underwater shock resistance. Although structural absorbed energy has a significant contribution in the shock resistance, soft coating can substantially reduce the total incident impulse at the initial fluid-structure interaction stage. Furthermore, a smaller fraction of incident impulse is transferred to the honeycomb coating with lower compressive strength.