有限元／间接边界元法求解浸水板振动特性

摘要

针对浸水板结构振动，考虑流体可压缩特性，利用间接边界元法计算附加质量矩阵，包含计算中奇异边界单元的处理。结合结构有限元法求解无限域浸水板的振动特性，通过编制的相应计算机程序，对浸水悬臂矩形平板进行了流体间接边界元与结构有限元耦合数值模拟；并对水下自由板进行了模态识别实验，实验结果验证了数值计算结果的可靠性。典型算例表明了流体介质改变了结构的动力特性，在低频段流体的可压缩性对结构的动力特性影响甚微；推导的流固耦合数值方法对研究浸水结构动力和声辐射研究有很好的参考价值。%With a focus on the structural vibration of a submerged plate and consideration for the compressibility of fluid, the added mass matrix was calculated by utilizing the indirect boundary element method ( IBEM) in this pa-per, including the treatment for the singularity boundary element in the calculation. In combination with the finite element method ( FEM) for structure, the vibration characteristics of a submerged plate in the infinite fluid field were calculated. Through the use of corresponding programming, a numerical analysis of the coupling between the indirect boundary element of the fluid and the finite element of the structure was conducted for the submerged canti-lever rectangular plate;in addition, a mode identification experiment was conducted on the underwater free plate. The experiment results verify the reliability of the numerical calculation results. The typical numerical example shows that the fluid medium changed the dynamic characteristics of the structure. At a low frequency band, the compressibility of the fluid had little impact on the dynamic characteristics of the fluid. The deduced numerical method for the fluid-structure coupling has excellent reference value for the dynamic research on a submerged struc-ture and the research on acoustic radiation.