Research On External Dynamics Of Ship Collisions And Internal Mechanics Of Ship Groundings

Ship collision and grounding are major threats for the sailing ships.Such accidents may lead to serious economic loss,ecological environment destruction and casualties.Therefore,it’s necessary to study the external dynamics response and mechanical performance of ship structures during ship collision and grounding accidents.The motion of the struck shipnd structural performance are coupled during ship collision and grounding.Neverthless,it is common to simplify the analysis by decoupling the process into external dynamics and internal mechanics.External dynamics of ship collision and mechanical performance of double bottom structures of ship grounding are mainly studied in the thesis.In the thesis,the external dynamics of ship collision and the mechanical performance of double bottom structures during ship collision and grounding are studied by the simplified analytical method and the nonlinear finite element method.The main work includes: 1.The existing methods for analyzing the external dynamics and internalmechanics of ship collision and grounding are introduced,and thebasic theory of the simplified analytical method is expressed in detail.Moreover,a review of the previous researches on ship collision andgrounding is presented;2.The external dynamics of ship collision is investigated in detail.Theship kinematic equations are solved by simplified analytical method,which based on some assumptions.Then,the energy dissipationduring collision can be obtained and the six dof motions can beverified by previous researches;3.A simplified analytical method is proposed for rapidly predictingresponses of double bottom structures subjected to grounding.Thetotal internal energy dissipated through the structural deformation andthe grounding resistance can be derived and verified by numericalsimulations.The results and conclusions obtained in this thesis can be used for assessing the collision energy dissipation and the structural damage rapidly and reliably during ship collision and grounding accidents,which are meaningful for structural design considering ship crashworthiness in the preliminary design stage.