波传播法求解低频激励下水中加端板圆柱壳的振动.docVIP

波传播法求解低频激励下水中加端板圆柱壳的振动 陈美霞，张聪，邓乃旗，魏建辉，谢坤 （华中科技大学船舶与海洋工程学院 湖北省武汉市 邮编430074） 摘要 文章采用波传播法研究了低频下水中壳体的振动与响应。水中壳体由有限长加流体载荷的圆柱壳和两端的圆形端板组成，其中外部流体载荷用无限长模型进行近似处理。为了模拟推动系统的激励及船体上某一点激励，文中分别考虑了不同位置的轴向载荷和径向载荷，讨论了单个周向模态下的位移在总位移中的比重。文中主要研究了四种载荷，即作用在端板中心的轴对称载荷、作用在端板与圆柱连接处的轴向载荷、作用在连接处的径向载荷和作用在壳体中间的径向载荷，比较得出了轴对称和非轴对称、同一点不同方向载荷、同一方向不同位置载荷的响应位移的不同。此外，文章研究了两端端板对不同载荷下水中壳体响应的影响，得出了端板主要抑制了壳体的较高阶模态下径向位移的结论。文中解析法结果与有限元法结果进行了比较，验证了该方法的正确性。 关键词: 波传播法；水下圆柱壳；端板；轴对称载荷；非轴对称载荷 中图分类号：U661.44 文献标识码：A Analysis of the low frequency vibration of a submerged cylindrical shell with endplates based on wave propagation approach Chen Mei-xia, Zhang Cong, Wei Jian-hui, Deng Nai-qi, Xie Kun (Huazhong University of Science and Technology, School of Naval Architecture and Ocean Engineering, Wuhan, 430074) Abstract The low frequency dynamic responses of a submerged hull are presented. The solutions are in the form of a wave travelling in the axial direction. The submerged hull is modelled as a finite fluid-loaded cylindrical shell closed at each end by circular plates. The external pressure acting on the hull due to the fluid loading is analytically calculated using an infinite model. Axial and radial excitations set at the different places of the hull are considered to simulate excitation from the propulsion system and the excitation at one point in the middle of the shell. Four cases of excitations are discussed in details, corresponding to axial excitation at the centre of the endplate, axial excitation at the edge of the endplate, radial excitation at the edge of the endplate and radial excitation at the middle of the cylindrical shell. The contributions from the individual circumferential modes on the hull structural responses are studied. Results are presented by comparing the frequency dynamic responses of shell under axi-symmetric excitations with asymmetric excitations, two excitations in different directions but at the same point, two excitations at different points but in the same direction