Research On Impact Resistance Of Ship Side Structure In Collisions

Ship collision is a kind of marine damage accidents of ships contacting with other objects. Catastrophic aftermaths will be brought by ship collision, such as personnel loss, vessel sinking, environment pollution and so on. Consequently, it is of great significance to investigate the damage mechanism of ship collision and then to improve the impact resistances of side structure correspondingly, no matter from the aspects of structural damage, oil leakage, environment pollution or life casualty.So far, the research methods of ship collision are mainly included simplified analytical method, experimental method and numerical simulation. In views of the limitation of accuracy of simplified analytical method and high cost of experimental research, the numerical simulation method is employed in the current study. Based on the understudied item namely International Science and Technology Cooperation Project, the current paper studies the impact resistances of ship from the point of ship structure. Employing the general dynamic finite element package ABAQUS/EXPLICIT, the present paper investigate the shock loading, damage deformation, mode and energy absorption of side structure, by means of numerical simulation combined with basic theory of ship collision dynamics and plastic dynamics. At the same time, the influences of relative stiffness of cross framing, liquid cargo in tank, impact position, impact velocity, impact angle and impact mass on impact resistances of side structure are studied systematically, which provides a great reference for the evaluation of crashworthiness of side structure and also the anti-shock rules on structural design and construction.In detail, the main contents of the present paper are as follows:(1) The current research status of ship collisions are reviewed from the aspects of theory,experiment and numerical simulation. At the same time, the advantages and disadvantages among the three above methods are analyzed, and the main contents of the paper and research method are illustrated in general;(2) The control motion of the ship collisions and its solving methods are introduced firstly; and the basic theory of numerical simulation and key technologies are discussed significantly;(3) The impact resistances of stiffened panels used in ships are studied and the numerical simulation method of ship collision is validated at the same time. According to the experimental results of stiffened panels struck by rigid striker which is conducted by experts over seas, 5 typical models are studied numerically and theoretically. Then the impact resistances of stiffened panels used in ships are investigated and the results show that the method taken in this paper has a high level of accuracy, which can satisfy the application of engineering.(4) The impact resistances of typical double-skin side structure are investigated employing the numerical simulation method. Based on the basic theory and key technologies introduced above, the model of ship collision is established, and finally the impact resistances of shipboard are studied from the aspects of contacting force, damage deformation mode and absorption and transition of energy;(5) The influences of collision parameter on shipboard during collision accidents are researched systemically. By changing the parameters of the model, the effects of relative stiffen of crossing frame, liquid cargo in tank, relative position of collision, collision velocity, collision angle and collision mass are studied in detail, especially the former two parameters are proposed firstly, which has a great significance in the evaluation impact resistance of shipboard during collision accidents.Based on the above main contents, the innovations of this thesis include two aspects:(1) Propose the concept of relative stiffness and apply it in the study of ship collision, completing the preliminary optimization successfully;(2) The influence of liquid cargo in tank on impact resistance of side structure is studied firstly in our country, which could provide a valuable reference for further study of related subjects.