Crashworthiness Of Typic Ship Side Structure

Ship collision is a dangerous accident that might cause disastrous results, such as the damage of hull, cargo spilling, environmental pollution and human injuries and deaths. So it is of great signification to research ship collision to improve ship's crashworthiness.In this paper, the FEM method is used to simulate the ship collision. The characteristics of collision force and energy transition .is studied. The effects of the shape of bow, the fluid cargo, and the relative position of ships and the velocity of the colliding ship on the ship's crashworthiness are discussed respectively. The major work and conclusions are listed as followings:Firstly, the current situation and major analysis methods of ship collision are outlined. The application of non-linear FEM to ship collision is reviewed and summarized. The theories and methods of numerical simulation about ship collision are systematically presented.Then, the influences of cone-shaped and spherical bows on the crashworthiness of ships are analyzed. The relations between the shape of bows with the forms of damage transformation and collision force and energy absorption .are studiedNext, three numerical simulation model building approaches: fluid-structure coupling, added mass and inertia equivalence are analyzed. Fluid-structure coupling approach can obtain an accurate result, but it costs too much work in building models and too much CPU time. Added mass approach can partly avoid fluid-structure coupling and cost less CPU time, however, it is still a great burden to build the whole ship model. Inertial equivalence approach requires very simple work on building model and apparently lessens CPU time, but constraints from boundary are generally difficult to specify.Next, applying the approach of added mass and fluid-structure coupling, the influence of the fluid cargo on the crashworthiness of ships is analyzed. It is shown that the results obtained from the two methods are very close but the added mass approach can improve the efficiency of the simulation.Finally, the influences of the relative position between ships and the initial velocity of the striking ship on the crashworthiness of ships are analyzed respectively. The results show that the relative position between ships has great influence on the crashworthiness. The effect of the colliding ship's velocity is less significant.