独立C型罐LNG运输船鞍座结构的数值模拟方法研究

Study on the simulation of type-C LNG carrier′s saddle structures

独立C型罐LNG运输船的储罐与船体结构非直接接触相连.储罐载荷由鞍座支承结构承担,C型罐鞍座布置特殊支座结构起到保护作用.支座结构的模型化研究对船体强度计算具有重要的现实意义.文中以某22000 m^(3)独立C型罐LNG运输船作为研究对象,根据《国际散装运输液化气体船舶构造与设备规则》的最新要求,推导椭球合成加速度的解析解,并自编程序实现全船有限元模型加载.为了更真实地呈现支承结构区域的应力状态,使用非线性间隙GAP单元模拟鞍座,讨论接触非线性边界及动/静摩擦对鞍座数值仿真的影响,量化不同数值模拟方案之间的差异.为独立C型罐LNG运输船鞍座结构强度计算提供可靠的技术方案,具有参考价值.

The cargo tank of Type C LNG carrier should be detached from the hull,then the tank including the cargo is held by the supporting structure completely,so that the saddle′s strength is critical to the design.According to the updated′International Code for the Construction and Equipment of Ships Carrying Liquefied Gases in Bulk′,the hull strength of a 22000 m^(3) type C LNG carrier with independent bi-lobe cargo tanks is assessed by the nonlinear finite element method(FEM).An automatic tool AWQLoading is developed for loading application of the equivalent design wave method.The feasibility of 5 different chock simulations including GAP element is investigated on the reaction forces and Von-mises stress distributions.It can be concluded that in order to understand the real working status of the saddle assemblies,the static/sliding friction is proposed to be considered as well as the contact,so as to provide a significant reference and a convenient software tool for the practical engineering applications.