The gradual increase in shipping and drilling activities in the Arctic regions has resulted in the increased importance of studying the structural safety of polar ships in various ice conditions.Rafted ice refers to a...The gradual increase in shipping and drilling activities in the Arctic regions has resulted in the increased importance of studying the structural safety of polar ships in various ice conditions.Rafted ice refers to a type of accumulated and overlapped sea ice;it is driven by external forces,such as wind and waves,and may exert high loads on ships and threaten their structural safety.Therefore,the properties of rafted ice and the construction of numerical models should be studied before exploring the interaction and collision between ships and rafted ice.Based on the nonlinear finite-element method,this paper introduces the cohesive element model for the simulation of rafted ice.The interaction between ships and rafted ice is studied,and the ice force of the hull is obtained.Numerical simulation results are compared with model test findings,and the effectiveness of the cohesive element method in the construction of the model of rafted ice materials is verified.On this basis,a multilayer rafted ice model is constructed,and its interaction with the ship is studied.The research unveils that rafted ice parts impede crack generation and slow down crack propagation to a certain extent.展开更多
In this study,a numerical method was developed based on peridynamics to determine the ice loads for a ship navigating in level ice.Convergence analysis of threedimensional ice specimen with tensile and compression loa...In this study,a numerical method was developed based on peridynamics to determine the ice loads for a ship navigating in level ice.Convergence analysis of threedimensional ice specimen with tensile and compression loading are carried out first.The effects of ice thickness,sailing speed,and ice properties on the mean ice loads were also investigated.It is observed that the ice fragments resulting from the icebreaking process will interact with one another as well as with the water and ship hull.The ice fragments may rotate,collide,or slide along the ship hull,and these ice fragments will eventually drift away from the ship.The key characteristics of the icebreaking process can be obtained using the peridynamic model such as the dynamic generation of cracks in the ice sheet,propagation and accumulation of ice fragments,as well as collision,rotation,and sliding of the ice fragments along the ship hull.The simulation results obtained for the ice loads and icebreaking process were validated against those determined from the Lindqvist empirical formula and there is good agreement between the results.展开更多
基金The National Natural Science Foundation of China(Grant Nos.52192693,52192690,51979051,51979056 and U20A20327)the National Key Research and Development Program of China(Grant No.2021YFC2803400)。
文摘The gradual increase in shipping and drilling activities in the Arctic regions has resulted in the increased importance of studying the structural safety of polar ships in various ice conditions.Rafted ice refers to a type of accumulated and overlapped sea ice;it is driven by external forces,such as wind and waves,and may exert high loads on ships and threaten their structural safety.Therefore,the properties of rafted ice and the construction of numerical models should be studied before exploring the interaction and collision between ships and rafted ice.Based on the nonlinear finite-element method,this paper introduces the cohesive element model for the simulation of rafted ice.The interaction between ships and rafted ice is studied,and the ice force of the hull is obtained.Numerical simulation results are compared with model test findings,and the effectiveness of the cohesive element method in the construction of the model of rafted ice materials is verified.On this basis,a multilayer rafted ice model is constructed,and its interaction with the ship is studied.The research unveils that rafted ice parts impede crack generation and slow down crack propagation to a certain extent.
基金This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement(Grant No.2017YFE0111400)the National Key R&D Program Strategic International Science and Technology Innovation Cooperation Key Specialities(Grant No.2016YFE0202700)+3 种基金the National Natural Science Foundation of China(Grant Nos.51579054 and 51639004)the Ministry of Industry and Information Technology’s High-tech Ship Research Project(Grant No.2017-614)Mr.Renwei Liu is supported by a two-year visiting student fellowship in University of California,Berkeley from Chinese Scholar Council(Grant No.201706680104)this support is gratefully acknowledged.The authors also graciously acknowledge Professor Shaofan Li of University of California,Berkeley and Fei Han of Dalian University of Technology for their guidance and fruitful discussion regarding this work.
文摘In this study,a numerical method was developed based on peridynamics to determine the ice loads for a ship navigating in level ice.Convergence analysis of threedimensional ice specimen with tensile and compression loading are carried out first.The effects of ice thickness,sailing speed,and ice properties on the mean ice loads were also investigated.It is observed that the ice fragments resulting from the icebreaking process will interact with one another as well as with the water and ship hull.The ice fragments may rotate,collide,or slide along the ship hull,and these ice fragments will eventually drift away from the ship.The key characteristics of the icebreaking process can be obtained using the peridynamic model such as the dynamic generation of cracks in the ice sheet,propagation and accumulation of ice fragments,as well as collision,rotation,and sliding of the ice fragments along the ship hull.The simulation results obtained for the ice loads and icebreaking process were validated against those determined from the Lindqvist empirical formula and there is good agreement between the results.
