Study On The Plastic Deformation Of Structure Under Ship-Ice Collision

In recent years,due to global warming,the polar glaciers are gradually melting and the coverage of sea ice is gradually decreasing.With the opening of the Arctic waters,more and more ships will navigate the Arctic region in the future.However,the Arctic waters is covered with a large number of icebergs and ice floes.The poor channel conditions make the navigation safety of polar ships not guaranteed,which brings some potential threats.Therefore,the study on the plastic deformations of ship structures under ice floe impacts has become an urgent research issue.In this thesis,the beam,non-stiffened plate and stiffened plate are selected as the research object.Combined with experimental and numerical methods,the plastic dynamic responses of the ship structures under ice floe impact are studied,the ice damages and plastic deformations of structures are investigated,and the influence law of ice shape on structural plastic deformation is revealed.The main contents are listed as follows:The model tests of ship plates under ice impact were carried out.The influences of ice models with different shapes and ship plates with different dimensions on the plastic dynamic responses of ship plates are studied,and the influence law of ice damages on structural plastic deformations is revealed.The model tests of ship plate under ice and rigid mass impacts were carried out,the plastic deformation of ship plate under the ice and rigid models impact were compared and analyzed,,and the law of plastic deformation reduction coefficient of ship plate under ice impact is investigated.The scale models of beams and stiffened plates were designed,and the experiments of scaled beams and stiffened plates under ice impact were conducted.The plastic dynamic responses of beams and stiffened plates under ice impacts with different shapes were studied.The characteristics of structural plastic deformation,stress levels during the ice impact were analyzed.The influence law of different shapes of ice models on the structural plastic deformation and the distribution of stress and strain during shipice impact were revealed.The numerical finite element simulations of the ice and ship plate impact were carried out by using ANSYS/LS-DYNA finite element commercial software.The experimental results are compared with numerical results,and the reliability of the finite element numerical method was analyzed.On this basis,based on the finite element numerical method,the laws of plastic dynamic responses under ice and rigid mass impacts with different shapes were studied.In addition,the structural plastic deformations of stiffened plates with different reinforcement forms under ice impact was investigated.Finally,for the actual side structure of polar ship and ice floes impact scenario,and a series of numerical studies of the ship side structure under the ice floe impacts with different shapes were carried out.The influence laws of ice shapes and impact positions on the plastic dynamic response of ship side structure were studied.The structural plastic deformations,ice damages and energy absorption of the side structure were analyzed,which can provide some references for structural safety assessment of polar ships.