Structural Dynamic Response Analyses On AHTS Side Colliding With Offshore Platform Pile

Ship–offshore platform collision is a complicated non-liner dynamic response under extreme large load in a very short time, It`s will lead to huge structural damage to ship and platform pile-leg. So we need to study the ship internal structural energy absorption in different collision conditions for reducing structural damage and providing theoretical guidance for ship improvement in future. This paper using finite element Method to analysis one of the most dangerous working conditions of AHTS-offshore platform pile collision-the state of one side collision and doing domain numerical simulation for the structural dynamic response of ship collision. This paper divided the ship crush-zone into two group: the vertical structure group and the parallel structure group. It makes collision speed, mass of ship and the diameter of the pile-leg as arguments to analysis the two group energy absorption. According to different kinetic energy absorption of two group to presenting an improved the ship side for reducing the pile-leg to absorb collision kinetic energy. The major research work and conclusion of this paper are summarized as follows:(1)Analysis the main forms of structural damage on crush-zone and based on this point first divided the crush-zone into two group: the vertical structure group and the parallel structure group. Analysis the transformational relation between the kinetic energy and ship internal energy, then check the internal energy of crush-zone structures and two group.According to energy absorption time history diagram and collision force time history diagram to analysis damage situation of crush-zone.(2) Study the transformational relation between the kinetic energy and ship internal energy on different collision velocity and comparison two group`s internal energy and collision force. When increase the collision velocity the growth rate of parallel structure group is faster than vertical structure group according to the result as well as max collision force.(3) Study the transformational relation between the kinetic energy and ship internal energy on different collision mass and diameter pile-leg and comparison two group`s internal energy and collision force. It makes little effect on ship`s internal energy and two groupenergy When use this two factor as arguments compared with use velocity as argument.(4)According to different sensitivity of two group when increase the collision velocity modification the side of ship to reduce pile-leg absorb the kinetic energy. Based on connected structure`s deformation when collision put forward different thickness plate effected on pile`s internal energy and analysis the relationship between the plate`s deformation and pile`s internal energy.(5)The paper presents three different broadside improved connection structure. based on the relationship between the plate`s deformation and pile`s internal energy and the damage forms of the parallel group. Then study the structure`s deformation, internal energy of ship and pile on two different collision speed. Finally it find the most optimal broadside fender connection structure for pile-leg using the collision date.