Due to the expansion of the use of polymer composite materials in industries, it is very
important to carefully examine the properties of these materials under different loading
conditions, including high speed impact. The phenomenon of underwater explosion is one of
the topics that has been receiving a lot of attention from researchers in the last few decades.
Underwater explosive formation, marine structures under explosive load, the effect of a marine
mine explosion on a ship's structure, etc. are examples of the application of the underwater
explosion phenomenon. In addition to bearing the hydrostatic pressure of water, marine
structures must be resistant as much as possible against loads caused by underwater explosions.
The strength-to-weight ratio of these structures should be as high as possible, so that the
designed structure is optimal in terms of consumables, energy and cost. In this research, the
analysis of underwater honeycomb sandwich panels under explosive load was done. First, a 2
x 4 meter honeycomb sandwich panel was subjected to explosive loading under the water
surface. The reinforced panel material was selected from three types of carbon-epoxy,
aluminum and five-layer steel with a thickness of 2 mm and a middle square grid with a distance
of 50 cm and a height of 20 cm. After extracting from Abaqus software, the results were
compared with each other to check the effect of each of these parameters on the behavior of the
sheet.