【作者】 康逢辉；

【导师】 姚熊亮；

【作者基本信息】 哈尔滨工程大学 ， 船舶与海洋结构物设计制造， 2011， 硕士

【摘要】 舰船的隐身性是一项至关重要的性能指标,对潜艇而言尤为重要。潜艇、鱼雷等各种水下航行器的典型舱段结构形式为有限长加筋双层圆柱壳结构。在潜艇结构中,其内部机械设备一般都安装在一定的基座上,壳体内部基座相当于各种连接结构的串联和并联,当设备激励基座面板振动时,振动波就会沿着这些连接结构将振动能量传递至其他结构,从而导致艇体结构发生振动,进而向海洋中辐射噪声。因此研究壳内基座结构对潜艇的减振降噪具有很现实的意义。当定常结构发生突变(质量、刚度等),结构阻抗也会随着结构的改变而发生变化,导致结构之间阻抗失配,使得振动波在突变截面处发生发射和透射,通过降低振动波传递效率,阻隔振动波能量向下游结构传递,从而达到减振降噪的目的。本文首先采用波动理论,分析结构突变时波型转换、阻抗失配等现象,分析了几种典型连接形式的组合板结构中(主要包括线性、“L”形、“T”形、“十”形、“(?)”形、“(?)”形等典型连接结构)振动波的传递特性,讨论了不同连接形式结构的反射和透射效率系数,为数值仿真和实验研究提供了理论基础。进而采用有限元／边界元(FEM/BEM)耦合法首先分析了低频段时有、无基座对双层圆柱壳振动声辐射的影响,然后根据第二章波动理论,设计高传递损失基座,即将原来的“T”形连接基座改为“(?)”形连接基座,并采用数值方法验证了低频段时的减振降噪效果。针对中频段时FEM/BEM和统计能量分析法(SEA)的不足,本文采用FE-SEA混合方法研究了双层圆柱壳中高频段振动声辐射特性,同时验证了所设计的高传递损失基座在中高频段时的减振降噪效果。最后根据实艇舱段进行模型实验,将两种基座形式分别置于壳内左右舷,通过实验对比,得到当基座连接形式由“T”形连接改为“(?)”形连接后的典型测点处的减振效果。将实验结果与数值仿真结果进行对比分析,验证数值仿真方法研究的准确性,从而为下一步数值仿真提供指导。更多还原

【Abstract】 The stealth of ship is an importance critical performance indicator and it is particularly significant in terms of submarines. Structure of typical cabin on submarines, torpedoes and other underwater vehicles are the finite stiffened double cylindrical shell. Inside the submarine structure, mechanical equipment is generally installed in a certain base. And the base structure is equivalent to the series and parallel of variety connections. As the mechanical equipment acting on the base panel, vibration wave energy will follow the connection structure transmission to other structures, leading to vibration of the hull structure, and then radiating noise to the ocean. Therefore, the investigation of the base in the shell structure has a very practical significance to the submarine noise and vibration reduction.When the stationary structure mutation (mass, stiffness, etc.), structural changes will result in resistance changes, leading to impedance mismatch between the structure, making the vibration wave reflect or transmission in the mutant cross-section. The purpose of reducing vibration and noise is achieved by reducing the wave propagation efficiency and holding up the energy of vibration wave passes downstream structural. Firstly, based on wave theory, the phenomenon of wave-type conversion and impedance mismatch was analyzed when the structural broken. Vibration wave propagation characteristics in combination of several typical joint board structure (typical connection structure including linear, "L "-shaped, "T"-shaped, "+"-shaped, "(?) "-shaped, "(?)"-shaped,) were studied. Efficiency of reflection and transmission coefficients in different forms of the structure connecting was discussed, which provided a theoretical basis for the numerical simulation and experimental study.Firstly the finite element/boundary element (FEM/BEM) coupling method was used to analyzed the effect of vibration and sound radiation of the base in double cylindrical shell in low frequency. Based on wave theory in Chapter II, the high transmission loss base was designed by replacing the "T"-shaped connection base to "(?)"-shaped connection base. Vibration and noise reduction effect in low-frequency was proved by the numerical method.Due to the deficiency of FEM/BEM and statistical energy analysis (SEA), sound radiation characteristics of the double cylindrical shell in the band were solved by the hybrid FE-SEA method, verifying the high frequency vibration and noise reduction effect of the high transmission loss base that designed.Finally, model experimental was carried and the two kinds of base form were respectively placed on two side of shell. Contrasting with experiment, damping effect at the typical measuring point can be obtained when respectively using "T"-shaped connection and "(?)"-shaped. The experimental results and numerical simulation results were compared to verify the accuracy of numerical simulation methods, and it can provide guidance for the next step numerical simulation.更多还原