极地船极限承载机理及塑性容限计算方法研究

With the development of North Arctic Channel and exploit of natural resources in Arctic, the polar ship will be the key equipment in the process of the construction of the Arctic. The sailing of the ship in Arctic may encounter the danger of low temperature, the extrusion and collision of ice. The mechanism of the ultimate bearing capacity of the polar ship will be studied and the calculation method of the plastic tolerance will be proposed. It is revealed the influence of the low temperature, ice on the ship hull in ultimate state. It is known that the yield strength of steel will increase as the temperature decrease, which will result in the increase of the structure ultimate strength. However, the ice extrusion and collision will decrease the structure ultimate strength under compression. All the factors will make the collapse mechanism of the polar ship complicated. The ultimate strength of the ship panel is studied considering the low temperature, ice extrusion pressure and dent induced by floating ice by the ways of theoretic, numerical and experiment methods in this project. Based on this, the collapse mechanism of the polar ship hull will be studied considering the coupling effect of ship and ice under low temperature. The process and calculation method will be proposed to provide the technology for the ultimate strength of polar ships. The assessment method of the plastic tolerance will be estimated according to the ultimate state design criterion. The method will be sought to predict the plastic tolerance and ultimate strength. The engineering plastic tolerance will be given preliminary. It will provide guidelines for the ultimate strength prediction and design of the polar ship and will supplement the polar ship rules.

随着北极航道的拓展及极地资源的开采，极地船舶将是极地开发和建设的关键装备。针对极地船在航行中的可能危险：低温、冰的挤压、碰撞，开展极地船极限承载机理及塑性变形容限的计算方法研究，揭示低温、冰对于极限状态下船体梁崩溃的影响机理。低温使钢材屈服强度增加而提高结构极限承载力，但冰的挤压和碰撞将会降低结构的压缩极限强度，因此，极地船的极限崩溃机理较为复杂。采用理论分析、数值计算及模型试验的方法，开展考虑低温、冰挤压以及碰撞凹陷损伤下极地船体加筋板结构极限强度研究；在此基础上研究低温下船冰耦合作用的极地船崩溃机理，建立冰区船舶船体梁极限强度的分析方法，完善冰区船极限强度分析技术；基于极限载荷的设计准则，建立极地船塑性损伤容限计算方法。探求极地船塑性变形容限及极限承载力的预报方法，初步建立适合工程应用的损伤容限，为极地船舶结构的极限强度预报和安全设计提供依据，有助于目前冰级规范的完善。

随着北极航道的拓展及极地资源的开采，极地船舶将是极地开发和建设的关键装备。针对极地船在航行中的可能危险：低温、冰的挤压、碰撞，开展极地船极限承载机理及塑性变形容限的计算方法研究，揭示低温、冰对于极限状态下船体梁崩溃的影响机理。首先采用理论分析、数值计算及模型试验的方法，提出了具有工程实用价值的考虑低温效应EH36钢动力本构模型，研究了船冰耦合作用的冰挤压力、浮冰多次碰撞的局部凹陷损伤，开展考虑低温、冰挤压以及碰撞凹陷及损伤下的极地船体加筋板结构极限强度研究，发现随着温度的不断降低，碰撞的应力减小，加筋板极限强度随温度的降低和应变率的升高而提升，最终给出了基于板格柔度和加筋板柔度折减的冰挤压力和凹陷损伤下加筋板极限强度预报公式，误差在15%以内。在此基础上，研究低温下船冰耦合作用的极地船崩溃机理，综合有限元和逐步破坏法的优点，建立冰区船舶船体梁极限强度的分析方法，完善冰区船极限强度分析技术，其误差在10%以内；基于逆可靠度分析法和极限载荷的设计准则，建立极地船塑性损伤容限计算方法，研究了不同温度和不同可靠度下极地船的塑性变形容限的规律。探求极地船塑性变形容限及极限承载力的预报方法，初步建立适合工程应用的损伤容限，本项目提出的计算方法和结果，为极地船舶结构的极限强度预报和安全设计提供依据，有助于目前冰级规范的完善。