水中复杂结构局部振动特性研究

Investigation of Local Vibration Characteristics of a Complex Structure in Water

讨论静水中板状组件的局部振动特性。比较了结构在空气中的局部振动频率与在水中的局部振动频率的变化趋势。当结构在静水中振动时，如采用流体有限元来计算流体的附加质量和附加阻尼，势必导致解题规模过大。本文用基于小参数展开法导出的两平行板间隙内流体的附加质量及附加阻尼系数的解析表达式来构造流体的附加质量阵和附加阻尼阵。这种处理法极大降低了解题规模。另外，还讨论了结构在静水中振动时。

The characteristics of local vibration of a plate type structure in water are studied in this paper.The varying tendencies of local frequencies of the plate type structure vibrating in air are compared with those in water. When a structure vibrates in water,large amount of computation will be unavoidable if the fluid finite element method is used to calculate the added water mass matrix and damping matrix.The added mass and damping coefficients deduced by means of a small parameter expansion method are introduced to form the added mass matrix and damping matrix,which decrease the computational work.Moreover,the effects of added mass and damping on free vibration characteristics of the structure are also discussed when the structure vibrating in water.