Based on a simple coupled cylindrical-conical shell, a new one stiffened with ribs and bulkhead was used to simulate a typical submarine afterbody. Adopting FEM and FM-BEM, the effects of bulkhead configuration, excitation direction, fluid effects, conical shell segment stiffness and hull damping factors on the shell acoustic radiation were studied. Firstly, the dry modes of the original shell were verified, and then the sound power of the new model in each case was calculated. Results showed that; under distributed axial excitation, the spherical bulkhead-stiffened shell has the minimum sound power and radiation efficiency; as the radial force is easy to excite circumferential modes of the shell, so it excites stronger sound than the axial force, but the effect of the axial force cannot be neglected; under radial excitation, smaller axial displacement and stronger radial displacement of the shell in water are discovered than those in air; the conical shell segment stiffness has minor effect on the sound suppression, while the damping can suppress the sound radiation well. The obtained conclusions provided a reference for optimal acoustic design of sub-marine afterbody.%在原有简单锥-柱壳体基础上,用肋骨、舱壁加强的锥-柱组合壳体模拟潜艇典型尾部结构,采用有限元(FEM)与快速多极边界元(FM-BEM)方法,研究壳体舱壁布置形式、激振力方向、流体介质、锥壳段刚度、壳体阻尼对声学性能的影响.在验证原模型干模态基础上,分别计算各因素对新模型辐射声功率影响,结果表明:在分布轴向力作用下,采用球舱壁加强的组合壳体水下辐射声功率及效率最小；径向力更易激起壳体周向模态,其激起的水声虽强于轴向力,但轴向力作用不可忽视；施加径向力时,壳体在水中的轴向位移小于在空气中,法向位移大于在空气中；锥壳段刚度对降噪无明显作用,适当增加壳体阻尼可降低声辐射.研究结论可为潜艇尾部声学优化设计提供参考.
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