冰和直立结构相互作用的静冰力可靠性分析     

李洪升  郑靖明  岳前进 《海洋学报》2001,23(4):106-112

我国渤海每年约有3个月的结冰期,冰与海洋结构的相互作用远较波浪为甚,因此有必要进行冰与海洋结构相互作用的可靠性分析.首先,采用热力学的方法根据每年实测的环境参数对海冰平整冰厚进行数值模拟计算,然后根据计算结果对不同重现期的极值冰厚采用极值统计法给出了极值分布,并与其他文献作比较.其次,以应变速率为海冰强度的主要影响参数,给出了海冰强度的概率分布.最后,以Schwarz公式为静冰力计算公式,结合得到的冰厚和冰强度的概率分布,采用映射变换法进行不同重现期静冰力的可靠度分析计算,并用蒙特卡罗重点抽样法进行模拟.  相似文献   

澜沧江源头科学探险考察中的冰川学考察     

李洪升  岳前进  郑靖明  朱元林 《冰川冻土》2000,22(1):5-6

Ice force is dominant for the offshore struc- tures in ice covered region, and mechanical properties of ice are the main factors to determine the ice forces. The mechanical propeties of sea ice, a special solid ma- terial, depend on its crystal dimension, c-axes direc- tion, anisotropy, temperature, stain-rate, stress-state and other factors. In the previous studies, some experi- mental models of sea ice strength were established. In this paper, sea ice strength was studied through a macroscopic and microscopic combination, which has the benefit to establish the theoretic model, and to des- cribe the deformation law, the stress-strain relation- ship and the destroy criteria. Based on the physical process of ice-structure interaction, the mechanisms of formation and expansion of the micro-crack were presented through the microscopic mechanism analy- sis of sea ice ductile-brittle transition. The criterion of sea ice ductile-brittle transition was obtained by ana- lyzing the Rice-Thomson model. The sea ice strength of the ductile-brittle transition zone calculated was ac- corded with the test result, which can be utilized to forecast the mechanical behaviors in the ice-structure interaction under general conditions, and to be theo- retic foundation for the ice force design.  相似文献