To improve the survivability of ship structures at underwater explosion, thin steel plates coated with polyurea were used to investigate the blast protection effect. During the experimental tests of bare steel plates at different standoff, an appropriate distance was selected as the reference standoff to perform the tests of coated plates. Experimental tests of different coating locations (front versus back) and coating thickness were carried out to study the influencing factors of blast resistance for metal substrate plates. Compared with the bare steel plates, the polyurea coating was found to reduce the deformation of the test plates at blast tests in both cases of the front and back surface locations of the polyurea layer. An increase in the coating thickness also mitigates substantially the deformation of plates. In addition, the properties of the material and the substrate-coating bond strength may also affect the protective effect of the polyurea coating.

Elastomeric material is used as blast-resistant structure because of its good mechanical properties.A series of underwater near-field explosive tests at different standoff distances were conducted to investigate the anti-explosion performance of steel structures covered with rubber and polyurea coatings. The experimental results demonstrated that both rubber and polyurea could enhance the blast resistance of test plates, and the polyurea coating performed better in reducing the deformation of steel plate and damage of steel structure. Compared with rubber, the polyurea has excellent mechanisms of energy absorption and dissipation, its mechanical behavior and molecular structure of elastomeric material determines the different ways of energy absorption and dissipation.

A new analytic model of aluminized explosive products based on the method of characteristics for planar isentropic flow is proposed herein. The contribution of Al oxidation in the explosion products is investigated analytically. The flow behind the detonation front cannot be treated as isentropic due to the Al oxidation in the products. To solve the nonisentropic flow field of aluminized explosives products analytically, the assumption of local isentropic process is proposed. Based on this assumption, the flow field behind the detonation front of aluminized explosive is a function of only the reacted aluminum mass fraction in each time range. The metal plate test was conducted with the metal plate driven by RDX/Al/wax (76/20/4) and RDX/LiF/wax (76/20/4). The reacted aluminum mass can be obtained indirectly from the experiment results. The reacted aluminum mass was then applied to the analytic model, and the velocity of metal plate driven by RDX/Al/wax (76/20/4) and RDX/LiF/wax (76/20/4) was calculated. The final velocity of the metal plate driven by RDX/Al/wax was 7.8% higher than that driven by RDX/LiF/wax.