阻尼处理多向加筋板的振动响应及声辐射

针对三种加强筋且横向加强筋为大小两种不同结构的典型加筋船板,考虑船板的弯曲振动,并计及船板内侧敷设粘弹性阻尼材料的阻尼处理和船板外侧重流体作用力,借助无限大板理论和经典波动法,建立了解析数学模型,导出了加筋船板在宽频单位力作用下的振动响应和远场水声辐射计算方法.通过典型实例的数值计算,讨论了小筋、阻尼等主要设计参数对辐射效果的影响.本文的研究成果对水声学工程设计有一定的指导价值.

The Vibration Response and Sound Radiation of Multi-Direction Stiffened Plate with Damped Treatment

The typical stiffened ship plate with three kinds of equidistant stiffeners is investigated in this paper. There are two kinds of transverse stiffeners among them, one kind is big and the other is small. The third kind of stiffener is vertical to them. Such structures are often found in engine cabins of surface warship. Considering the bending vibration of the ship plate as well as the viscous elastic damped material and the effect of heavy liquid acting at the outer layer, the mathematical model of the ship plate is established and the forces of these three kinds of sliffeners are derived based on the infinite big plate theory and classical wave method. And then with the help of double Fourier transform and inverse transform, the vibration response of the plate and sound radiation in water of far field under the impact of wide frequency unit force are deduced. At the same time, the vibration response and the sound radiation of a plate without stiffeners are also given for comparison. Due to the influence of stiffeners, the curves of sound have many peaks and are undulate at the corresponding frequencies. The use of damped material and small stiffeners will make contribution to the sound design, but how to take these steps is still a problem. So the potential of optimizing exists. In order to get the experience, numerical calculation are carried out for several typical structures and the result charts are given. The main design parameters, such as the interval and the dimensions of small stiffeners, the material and the thickness of damped treatment, are analyzed and discussed. Some useful conclusion has been drawn. Increasing the layout of small stiffeners and optimizing them will reduce the sound level. Using pertinent damped material with appropriate thickness will be of benefit to sound design.