预应力和流固耦合效应对水下壳结构振动特性影响研究

对于水下结构,流体对结构模态频率的影响主要体现在预应力效应与流固耦合效应两方面.为研究水下壳结构固有频率对这2种效应的敏感度,本文首先计算某水下壳体在空气中的模态,然后研究壳结构在不同水深工作产生的静水压对其固有频率的影响,最后使用声固耦合的方法计算了流固耦合效应下的壳体湿模态.计算结果表明:流固耦合效应占主导因素,但随着壳体工作水深(预应力)的增大,预应力效应对水下壳体频率的影响也逐渐显著.因而,在开展水下结构动力学设计时,不仅要重点考虑流固耦合效应对结构固有频率的影响,还应关注结构实际工作环境下的应力状态,分析其对结构固有频率的影响.

The study of effects of pre-stress and fluid-solid interaction effect on vibration properties of underwater shell structures

For the underwater structure, the influence of fluid on the modal frequency of underwater structure is mainly reflected in the two aspects of pre-stress effect and fluid-solid interaction effect. In order to study the sensitivity of underwa-ter structure modal frequency to these two effects, this paper firstly study the modal of an underwater shell in the air, then the effect of pre-stress effect on structure modal is analyzed. Finally, the method of acoustic-solid interaction method is used to calculate the wet modal of the shell under the fluid-solid interaction effect. The computed results show that the fluid-solid in-teraction effects is the dominant factor, but as the depth of the water (pre-stress) increases of the shell works, the effect of pre-stress effect on the frequency of the underwater shell is also becoming apparent. Therefore, in the design of underwater structure dynamics, should not only focus on considering fluid-structure interaction effect of underwater structure vibration, also should pay attention to the stress state of structure in the actual work environment, to analyze its influence on structure vibration