Analysis of influence of different damage forms on residual ultimate strength of ship structure

Abstract：Objectives The assessment of the residual ultimate strength of the hull structure is of great significance to ensure the safety reserve of damaged ships. In order to accurately evaluate the residual strength of a ship in the extreme case of collision, it is necessary to deeply analyze factors such as the shape of the breach, the area of the breach, and the location of the breach of the hull structure, so as to understand their influence on the residual ultimate strength of the hull structure. Methods Based on the simplified numerical calculation method, a series of structural response calculations were carried out for collisions at different speeds, angles, and impact locations to obtain the damage conditions of hull structures. Combined with the nonlinear finite element software to carry out the study of the residual ultimate strength of the ship, to investigate the influence of different breakage forms on the residual ultimate strength of the ship structure. Results The two factors that significantly affect the size of the residual ultimate strength of the ship are the area and location of the breach, and the shape of the breach has smaller influence on the size of the residual ultimate strength, but it has a greater influence on the structural fracture pattern. Under the condition of consistent breach shape, with the increase of area, the residual ultimate strength of the structure decreases. Under the condition of similar breach areas,, with the edges gradually become sharp, the angle between the fracture path and the vertical plane gradually decreases, and the location of the fracture gradually moves towards the middle of the structure. Conclusions The research results can serve as the basis for the evaluation of the residual ultimate strength assessment of the ship, and provide reference for emergency handling after ships suffer collisions during navigation.