水中加肋球壳振动和声辐射研究

考虑球壳内表面设置加强环肋，借助狄拉克δ函数引进环肋对壳体的作用，建立水中弹性薄球壳的声振耦合系统的运动微分方程．基于势流理论和系统的耦合方程，通过变量的勒让德级数展开求解方程，演绎出可覆盖中、低和高频激励的加肋球壳的振动和声辐射的解析解．依据所得公式和相应的数值计算重点分析了加强肋对结构声辐射特性的影响．结果表明：由于环肋的存在，大大增加了耦合系统共振频谱的复杂性，对于中频激励，环肋的设置能明显地改变结构的声辐射特性．该方法有好的计算精度和计算速度．

Vibration and acoustic radiation from a stiffened spherical shell in water

Based on the motion differential equations of vibration and acoustic coupling system for thin elastic spherical shell with rings attached to shell, by means of expanding field quantities as Legendre series method, an analytic solution was derived for the solution to the vibration and acoustic radiation from a submerged stiffened spherical shell with ribs having computational effectiveness and precision for arbitrary frequency range. It was easy to analyze the effect of internal ribs on the acoustic radiation field by using the formulas obtained. It was concluded that the internal stiffening ribs could change the mechanical and acoustical characteristics of the shell, and make the coupling system have a rich resonance frequency spectrum. The presented method could be used to study the acoustic radiation mechanism of structure.