基于模态滤波的板壳类结构空间均方振速估算方法

针对船舶、航空航天等工程领域中板、壳类结构振动噪声评价问题,将广泛应用于控制工程中的模态滤波理论引入到结构振动评估领域,建立了一种估算结构空间均方振速的新方法.该方法的特点是能在激励源信息未知的情况下,以布置在结构表面有限个振动传感器测量得到的振动响应作为主要输入,估算板、壳类结构的空间均方振速,从而评价结构的整体振动状态.依据该方法对一矩形平板结构受点力、线力和面力等3种典型的激励源作用下,通过少量结构振动测点的振动信息,分别对其空间均方振速进行了数值验证;同时利用一水下加肋圆柱壳结构进行了试验验证.数值和模型试验验证结果表明：利用该方法评估得到的振动速度谱线特征与精确解和实测值基本一致,评估误差在2 dB以内,满足工程应用精度要求.该方法可以应用于工程中板、壳类结构振动噪声评价和振动状态的在线监测评估.

Estimation of the Spatial Quadratic Velocity of Shells andPlate Structures Based on a Modal Filter

Aiming at structural vibration assessment problems in the aerospace and ship engineerings,anew method for estimating the spatial quadratic velocity of plates and shells is presented using the theory ofmodal filter that has been widely used in the field of control engineering. The innate feature of the proposedmethod is that it can be applied in the case where the information concerning excited forces is unknown. Tovalidate the method,the spatial quadratic velocities of a rectangle flat plate excited by three different typesof forces,namely point forces,line forces,and surface forces,are estimated respectively,using the vibration information from a few measurement points. Meanwhile,various tests were carried out on an underwater ring stiffened cylindrical shell for further verification. The results show that the suggested method is precise in estimating the vibration spectrum,where the error is within 2 dB. Overall,the method can be usedto estimate the spatial quadratic velocity of the structures in both actual practices and online monitoring.