液体一阶晃动模态的试验识别

Experimental Identification of the First Sloshing Mode of Liquid

摘要: 液体的晃动模态(自然频率、振型与阻尼比系数)是贮液结构设计以及振动控制的重要参数，本文采用人工激励的方法可容易激发出容器内液体自由表面的一阶模态运动，撤除激励后液体表面按一阶振型作自由衰减振动，采用多个激光位移器测量液体表面多个点的波高自由衰减曲线，从而可得到液体晃动的一阶自然频率、振型和阻尼比系数，试验测得的晃动频率、振型与理论结果吻合良好，本文的试验模态识别方法适合于任意形状的容器。

Abstract: The sloshing mode of liquid (natural frequency, mode shape and damping ratio) is the important parameter for the design of liquid-storage structure and the vibration control. In this paper, the artificial excitation is used to stimulate the first mode motion of the liquid free surface in container. The decaying free sloshing in the first mode will occur on the liquid free surface after removing the excitation. The decay curves of free vibration of wave height on the several points of liquid surface can be simultaneously measured by the several laser displacement sensors. Thus, the first natural frequency, mode shape and damping ratio of liquid sloshing can be obtained. The experimental frequencies and mode shapes agree well with theoretical results. The present experimental identification method is applicable to the arbitrary tanks.