Ship shock trials have been conducted in many countries for shock qualification of ship integrity, systems and subsystems. The ship shock trial identifies design and construction deficiencies that have a negative impact on ship system and integrity. It also validates shock hardening criteria and performance. Ship shock trial is always performed based on far-field underwater explosion using large explosive charge size with long standoff distance. However, ship shock trials are costly. As a possible alternative, numerical modeling and simulation may provide viable information to look into the details of survivability of ship.

The ship is surrounded by semi-infinite fluid volume. To capture the fluid-hull structure interaction effect and also bulk cavitation effect due to free surface, the fluid volume needs to be modeled and coupled to ship. The question arises as to (1) how much fluid volume must be modeled as a minimum, and (2) how to treat the radiation boundary at the exterior boundary surface of fluid volume. This paper has investigated the minimum fluid volume required to capture the correct response with proper radiation boundary applied on fluid exterior surface.

Ship shock analysis was conducted using finite element based coupled ship and fluid model (Figure 36.1). Three dimensional ship shock modeling and simulation has been performed and the predicted results were compared with ship shock test data (Figure 36.2). Surface ship shock analysis approach is presented and the important parameters are discussed.

Figure 36.1: Dry Ship and Coupled Fluid-Ship Models

Figure 36.2: Vertical Velocity Responses

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