Research On Numerical Simulation For Collision Response Of Semi-Submersible Platform

Offshore platforms work in the complicated sea conditions, where vessels passing by may collide to the platform due to navigational operation errors, and the vessels may be disturbed by winds, waves or current when docking. As the deep-water semi-submersible offshore platform work in even worse sea conditions, the collision accidents are even harder to avoid. Collisions between ships and marine structures often result in disastrous consequences such as structural damage, casualties and cargo leakage. Therefore, it is of great importance to improve the resistibility of ship, no matter what consider economy, safety and protecting environment.The marine structures collision is a high-energy process with a powerful impact loading dynamic response and has obvious non-linear dynamic properties. The column structure exposed to the waterline of a semi-submersible offshore platform is the most vulnerable part during a ship collision process. In this paper, a numerical simulation of the collision process between a 27000t tanker and a semi-submersible platform working in a water depth of 3,000 meters is conducted. In this numerical simulation, a simplified computation model is employed for the non-collision zone, the Cower-Symonds model and the ANSYS/LS-DYNA explicit non-linear dynamic analysis software are used. Through this simulation, the form of the impact force, energy absorption and structural damage deformation are obtained.In order to discuss the various collision factors during the damage process of the offshore platform collision, this paper analyzes different parameters on the deformation of structural damage after the collision, the collision force and energy absorption while conducting numerical simulation based on different collision speeds, qualities, and the initial collision angles of ships in the example of the collision between the offshore platform and a 27000t tanker at the speed of 4m/s. At the end, based on the analysis of the results, some basic suggestions and reference for anti-collision measures are given.