【作者】 李军向；

【导师】 谢官模；

【作者基本信息】 武汉理工大学 ， 固体力学， 2004， 硕士

【摘要】 随着水声探测潜艇的手段和方法以及带有声制导的水下武器的不断完善，对潜艇的声学性能的要求越来越高。在保证潜艇结构强度的前提下，安静性和隐身性对提高潜艇的战斗力至关重要。声纳所探测的潜艇噪声包括两部分，一是螺旋桨运转带来的水动力噪声，二是潜艇主机工作时产生的不平衡力和力矩引起潜艇结构振动，带动流场振动从而辐射噪声。通过改进潜艇尾部线型设计，已将水动力噪声降到比较低的程度，而结构噪声则复杂得多，与许多因素有关。本文寻求潜艇耐压和非耐压船体结构受激振动辐射噪声的计算方法，分析潜艇结构辐射噪声的影响因素，对降低艇体振动和辐射的噪声，以及潜艇结构进行隐身优化设计、提高其战斗力具有十分重要的理论指导意义。 本文在研究潜艇结构在水下的总体振动和声辐射特性时，将其简化为加筋(环肋、舱壁和纵骨)单层(耐压)或双层(耐压和非耐压)无限长圆柱壳，着重研究了加筋单层壳在水下的振动与声辐射特性。壳体的运动方程采用较为简单的Donnell理论描述，运动方程中包括了激励力、加筋结构(环肋、舱壁和纵骨)和流场对壳体的作用力，从而组成流场-结构的耦合振动方程，并进一步将方程中的位移用速度表示，然后沿轴线方向进行Fourier变换，将速度和各项荷载沿圆周方向进行模态展开，得到了壳体振动的模态运动方程。然后用Fourier变换分别求解环肋、舱壁、纵骨和流场的运动方程，将它们对壳体的作用力(力矩)用壳体周向模态展开，利用它们与壳体在连接处位移连续条件以及Fourier逆变换得到用壳体速度表示的模态相互作用力(力矩)。将以上各项荷载和激励力代入壳体的模态运动方程，可求得壳体的模态径向速度，然后由稳相法得到远场声压的解析解。 本文用MATLAB编制程序求解了单层壳在径向激励力作用下的远场声压级，分析了模态截断数、纵骨、舱壁板、结构阻尼等因素对壳体远场辐射声压的影响，为准确计算加筋双层壳在水下振动和声辐射特性奠定了基础。 最后，本文还导出了由实肋板连接的加筋双层壳在水下振动和声辐射的理论公式。加筋结构和单层壳的情况相同，加筋结构和外流场对壳体的作用武汉理工大学硕士学位论文力的推导与单层壳的情况相同。更多还原

【Abstract】 With the progressive development of underwater acoustic detection and acoustic-guided weapons, more advanced requirements are imposed upon the acoustic properties of submarines. Provided that the submarine structure strength is met, noise is vital to submarine battle ability. The submarine noise detected by sonar consists of two parts: propeller-generated hydro-dynamical noise, which can be greatly reduced by improving the submarine rear shape; radiated noise from the submarine structure excited by the centrifugal forces (moments) of rotatory machine, which is more complicated and influenced by many factors. This paper is aimed to provide a computational method of sound radiation from the pressure and non-pressure hulls of submarines subjected to harmonious point forces. It is significant for reducing vibration and sound radiation of the submarine hull, guiding the optimization design of submarine and enhancing its battle ability.The submarine structure is simplified to single or double infinite cylindrical shell stiffened with rings, bulkheads and stringers, focusing on underwater sound radiation from the single shell. The shell motion is described by Donnell’s theory including excitation forces and reactions of rings, bulkheads, stringers and fluid, which leads to the fluid-structure coupling vibration equation. Expressing displacements by velocities, applying modal expansion circumferentially and Fourier transformation longitudinally result in the shell’s modal equations of motion. Then Fourier transformation is employed to solve equations of motion of the rings, bulkheads, stringers and fluid respectively, with their reactions (moments) expanded by the shell’s in-vacuo modes. By means of continuity conditions on the interfaces between the shell and the stiffeners as well as the fluid, and inverse Fourier transformation, the modal reactions (moments) are finally expressed by the shell’s modal velocities. Substituting the above modal reactions (moments) and excitation forces into the shell’s modal vibrationequations, the shell’s radial modal velocity are obtained from which the far-fieldsound pressure derived by stationary phase method can be calculated.MATLAB procedure is coded to compute the far-field sound pressure levels of the shell excited by radial point force. The influences of modal truncation, stringers, bulkheads and damping on the shell’s far-field sound pressure are analyzed, laying down the basis for accurate analysis of the sound radiation from fluid-loaded reinforced double cylindrical shells.In addition, the sound radiation from fluid-loaded reinforced double cylindrical shells, periodically connected by slabs, is formulated.更多还原