圆柱壳结构入水过程的流固耦合仿真与试验

大型圆柱壳结构从空中入水时,在水流强大冲击下将发生较大变形甚至断裂.为提高该结构的耐撞性,将仿真与试验相结合.通过静态拉伸和动态SHPB试验获取两种备选材料的非线性本构关系,拟合出塑性随动材料模型.制作了1∶ 10简化缩比模型,进行了跌落试验与仿真分析.建立了真实结构与全尺寸的薄壳、水、空气耦合的多物质仿真模型,通过ALE/Lagrange无侵蚀罚函数耦合算法,实现了入水过程的有限元仿真分析.找到了初始方案的不足之处,提出了改进方案并进行了仿真验证分析.该方法同样适用于其他具有大变形和非线性的流体冲击问题. 

Simulation and experiment of cylinder shell structure dropping into water based on fluid structure interaction

When dropping into water from the air, large cylinder shell structures may suffer larger deformation or collapse due to the strong water impact. To improve the structural crashworthiness, the simulation was done, combined with corresponding experiments. Through the static tensile and dynamic SHPB tests, the nonlinear constitutive relationships of alternative materials were obtained, and the corresponding plastic-kinematic material models were built. Simplified models scaled 1∶ 10 were dropped into water for test, and their simulation was done also. Full sized structure in detail and partial fluid domain were modeled, composed by thin-shell, water and air. Based on the ALE/Lagrange penalty function coupling algorithm without erosion, the process dropping into water was simulated by finite element method(FEM). Then the weakness of original design was found, and an improved scheme was proposed and verified by simulation. The proposed approach is also applicable for other fluid impact problems related to large deformation and nonlinear.