基于陆上振动测试的水中圆柱壳结构声振响应计算方法

Calculation method of underwater acoustic and vibration response of cabin segment based on onshore vibration test

  • 摘要:
      目的  旨在研究建立基于陆上振动测试结果计算水下圆柱壳结构声振响应的方法。
      方法  引入轴对称边界元法描述壳体的辐射声场,通过边界元积分方程的数值求解,得到母线上节点声压与速度的关系,再经周向拓展构造出整个壳体外表面的声辐射阻抗矩阵和声振传递函数。基于水下圆柱壳结构低阶振型与陆上圆柱壳相同的假设,结合陆上圆柱壳的模态振型和声辐射阻抗矩阵,计算模态附加质量及模态附加阻尼。
      结果  通过研究,建立了基于陆上模态的水中圆柱壳的固有频率计算公式,提出了以空气中振动响应为输入并基于模态叠加法的圆柱壳结构水下振动响应和声辐射特性的计算方法。
      结论  通过典型的含内部结构圆柱壳的数值算例结果表明,上述方法能够满足工程所需的精度要求。

     

    Abstract:
      Objective  This paper proposes a method for calculating the acoustic and vibration response of underwater cylindrical shell structures based on land-based vibration test results.
      Methods  An axisymmetric boundary element method (BEM) is introduced to describe the radiation acoustic field of the shell. The relationship of acoustic pressure at the nodal point of the generatrix with velocity is obtained by solving the numerical solution of the boundary element integral equation, then the acoustic radiation impedance matrix of the outer surface of the shell and acoustic transfer vector (ATV) are constructed. Based on the assumption that the low-order vibration mode of an underwater cylindrical shell is the same as that of an onshore cylindrical shell, combined with the modes and acoustic radiation impedance matrix of an onshore cylindrical shell, the modal added mass and damping are calculated.
      Results  The natural frequency calculation formula of the underwater cylindrical shell is established on the basis of the onshore mode, and the calculation method of underwater vibration response and acoustic radiation characteristics with the vibration response in air as input is obtained based on mode superposition method.
      Conclusion  The numerical results of a typical cylindrical shell with internal structure show that the method meets the engineering accuracy requirements.

     

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