轴对称声振耦合的边界子波谱与有限元耦合方法及应用

在轴对称结构有限元和轴对称Helmholtz积分方程的基础上,建立了轴对称弹性结构构声振耦合的边界 子波谱有限元耦合方法,该方法能处理任意边界条件。采用提出的耦合方法研究了含有壳、肋、板复杂结构的水下航行 器的声辐射,给出了轴对称圆环肋的刚度矩阵和质量矩阵。进行了声振耦合的模态分析,研究了航行器的轴向激励、侧 向激励的声辐射;计算了0～2kHz的频率响应。结果对水下航行器的研究设计有一定的参考价值。

Application of Coupled Finite Element and Wavelet Boundary Spectral Method to Fluid-Structure Interation on Axisymmetric Bodies

On the basis of finite element method and Helmholtz integral equation for axisymmetric bodies with arbitrary boundary conditions, the boundary quantities are expanded in wavelet series along the generator of the body, and a coupled method linking wavelet spectrum and finite element is formulated for solving fluid-stucture interaction on axisymmteric elastic bodies with arbitrary boundary conditions. The new approach reduces a three-dimensional formulation to one-dimensional one along the generator of the body and forms a highly spare matrix system which can be solved rapidly by sparse solvers. The new technique was employed to investigate the undrwater acoustic radiation from a comlicated structure submerged in water, which is composed of shells, ring frames and plates, The axisymmetric stiffness and mass matrices of the ring frame of the submerged structure are derived. The modal analysis of the structural-acoustic coupling is performed. The acoustic radiation resulted by axial and transversal excitations is evaluated. The acoustic frequency responses from 0 to 2k Hz are provided. Some conclusions are valuable for the acoustic design of submerged structures.