二维晃动自然频率与阻尼比系数的试验识别  

Experimental identification for the natural frequencies and damping ratios of two-dimensional sloshing

作　　者：王立时[1] 李遇春[1] 张皓[1] 

机构地区：[1]同济大学土木工程学院,上海200092

出　　处：《振动与冲击》2016年第8期173-176,206,共5页Journal of Vibration and Shock

基　　金：国家自然科学基金资助项目(51279133)

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。在液体晃动的模态试验中,需要激发液面的模态运动,但液面的对称模态运动一般较难激发出来,使得对称模态参数(特别是阻尼比系数)难以精确识别。采用参数激振的方法对矩形、U形和圆形截面容器进行竖向激振,容易激发出液体表面的前四阶模态(包括对称模态)运动,撤除激励后液体表面按某一特定的振型作自由衰减振动,通过激光测量液体表面波高的自由衰减曲线,从而精确得到液体晃动的自然频率与对应的阻尼比系数,测得晃动频率与理论频率结果吻合良好,表明该试验识别方法有效。The modal parameters of sloshing fluid are essential to the design of liquid tanks and vibration control. In the modal experiment of fluid sloshing, the modal motions of free liquid surface should be excited. However, the symmetric-mode motions of free surface are difficultly stimulated, therefore the modal parameters （especially for the damping ratios） of the symmetric modes cannot be accurately measured. This paper applied parametric vibration method to excite two-dimensional （parametric） sloshing in rectangular, U-shaped and circular tanks. The first four mode motions （ including the symmetric-mode motions） of free surface were easily aroused. After stopping the external excitation, a free damped-vibration response of a certain mode on the free liquid surface could be obtained with the laser displacement sensor. The sloshing natural frequencies and the corresponding damping ratios were precisely obtained. The experimental and theoretical frequency results agree well, which validates the present experimental method.

关 键 词：二维晃动 参数振动 实验 液体 模态参数 

分 类 号：O353.1[理学—流体力学]