部分入水悬臂梁的自由弯曲振动固有特性研究

Study of Free Vibration of Cantilever Beam Partially Submerged in Water

针对部分入水悬臂梁的自由弯曲振动固有频率问题,根据结构动力学和流固耦合动力学理论,将水视为理想流体并忽略水表面自由振动波的影响,从而得到了部分入水悬臂梁的自由弯曲振动的振动控制方程。应用Galerkin法离散求解该振动方程的特征值,并采用以ANSYS软件为平台的有限元方法进行模态计算,然后将两种方法得到的结果进行比较,并分析了前两阶固有频率随水深的变化规律。结果表明:两者计算结果基本一致,并且系统的前两阶固有频率随水深的增加而降低,直至满水时降到最低值。

Aiming at the free bending vibration of cantilever beam partially submerged in water,the method of structure dynamics and fluid-structure interaction was used to set equations with the simplification which the water was ideal liquid and the vibration wave of water surface was neglected. Then,the Galerkin method was used to discrete equation and to solve it. For comparison,FEM was applied to make mode analysis. Finally,the change law of the initial second order natural frequency and water depth was studied. The results show that the result of two methods is almost same and the initial second order natural frequency decreases with increasing of water depth.