An analytical model for predicting the mean crushing strength of stiffened plated structures under quasi-static crushing loads is developed. Dynamic effects are included into the model by considering the strain-rate sensitivity of material. Verification examples are shown to validate the accuracy and applicability of the proposed method. As an illustrative example, the model is applied to assessment for collision strength performance of bow structure for an actual chemical product carrier colliding with a fixed object.
Ship collision and grounding can result in structural damage, marine pollution dependent on cargo type, and hull girder collapse after the accident. The task of protecting against such environmental disaters or vessel loss due to potential accidents is complex, but can generally be divided into two major groups, namely active and passive safety methods (Pedersen 1995). The active method is aimed at preventing an accident to occur. This approach includes auto-pilot system of the vessels, crew-training program for instance with realistic simulators for ship operations, and traffic control systems. The passive safety method works after an accident has occurred. It is designed to mitigate the risk of serious consequences, such as ingress of sea water, outflow of hazadous cargo, and hull girder collapse. The latter is related to the improvements of structural crashworthiness, and rapid salvage and rescue operations. The present study is concerned with application of the passive method on the improvements of structural crashworthiness in ship's bow collision. For that purpose, it is necessary to better understand the mechanics of ship collision such that the structural safety of vessels against accidental loading can be improved. During ship collision, typical failure modes include crushing of structural elements. Much research have been focused on investigating the behavior of structural components under crushing loads.