基于模态模型的水下薄板声辐射响应变异性分析

摘要

利用不考虑流体附加阻尼的流体加载结构的模态矩阵结合固有频率和模态阻尼比建立了求解水下结构振动响应的模态分析模型，并将单自由度分析模型应用于水下结构辐射声功率的变异性计算。分别计算了板厚度变化和板上集中质量分布变化时的声辐射响应变异性，并与采用有限元-边界元耦合方法得到的结果进行了比较。数值计算结果表明：基于模态模型的单自由度分析方法仅通过固有频率的变异性即可估计出辐射声功率的变异性，在结构固有频率的扰动范围给定时，通过绘制包络线可以预报辐射声功率的扰动范围。%Modal model is developed using fluid-loaded undamped real mode shapes combined with modal frequencies and modal damping ratio for vibro-acoustic response computation of water-loaded structures, single degree of freedom analysis method is then employed for response variance calculation of acoustic radiation. The numerical results of the response variance of acoustic radiation from a plate with different thickness or different distribution of lumped masses are given and compared with finite element-boundary element coupling method. The results show that the single degree of freedom analysis method based on the modal model gives rapid approximation of the variance of radiated power due to variance in natural fre-quencies. The perturbation range of the radiated power can also be predicted by drawing the envelope with known perturbation range of the natural frequencies.