A time domain computation method for dynamic behavior of mooring system

A quasi-steady time domain method is developed for the prediction of dynamic behavior of a mooring system under the environmental disturbances, such as regular or irregular waves, winds and currents. The mooring forces are obtained in a static sense at each instant. The dynamic feature of the mooring cables can be obtained by incorporating the extended 3-D lumped-mass method with the known ship motion history. Some nonlinear effects, such as the influence of the instantaneous change of the wetted hull surface on the hydrostatic restoring forces and Froude-Krylov forces, are included. The computational results show a satisfactory agreement with the experimental ones.

Numerical investigation of thermocapillary migration of the drop for large Marangoni numbers

An axisymmetric model is adopted to simulate the problem of unsteady drop thermocapillary motion for large Marangoni numbers. Front tracking methods are used in the investigation. It is found that the non-dimensional drop migration velocity will decrease with increasing Marangoni number. This agrees well with the experimental results obtained from the 4th Shen-Zhou space ship. In the meanwhile, this is also the first time for numerical simulations to verify the experimental phenomenon under large Marangoni numbers.

三峡升船机系统动态响应分析

根据三峡升船机最新设计报告,采用有限元软件ANSYS构建了升船机系统有限元模型,包括承船厢、提升钢索、滑轮组、平衡重、厢内水体、驱动机构和刹车机构;通过数值模拟,对升船机系统进行了模态分析及动态响应研究,内容包括升船机系统的流固耦合模态及其在各种工况(起动、刹车、事故)下的动态响应和影响因素分析,如弹簧刚度、误载水深、阻尼、承船厢的位置等.计算结果表明:对于升船机这样一个复杂系统,该文所建立的有限元模型及数值算法是合理的,其结果可为升船机系统整体设计提供必要的参考.

地震作用下大型升船机结构的时变动力可靠度

利用三维有限元方法对三峡升船机塔柱结构的动力学特性及随机地震响应进行了计算分析,结果表明塔柱结构柔度较大,其项部节点随机地震位移响应为中宽带过程.在此基础上,采用首次超越破坏机制,以塔柱结构顶部典型位置的位移限值为可靠度界限,对设计地震烈度下升船机塔柱结构的时变动力可靠度进行了计算分析,得到了塔柱结构设计基准期内的时变动力可靠度,并讨论了可靠度界限值的随机性对结构抗震时变可靠度计算结果的影响,建议升船机结构抗震可靠度计算模型采用Markov过程假定.该文可为升船机结构设计及安全运行提供必要的参考.