大潜深耐压球壳结构的声振耦合特性研究

Vibro-acoustic coupling analysis of deep submerged spherical shells

考虑剪切变形和转动惯量,建立计及静水压力作用的厚球壳声振耦合模型,针对机械点力激励,计算分析厚壁几何特征和静水压力载荷对大潜深耐压球壳声振耦合特性的影响。结果表明:厚壁球壳耦合振动响应远小于薄壁球壳,但两者水下声辐射的差距大幅缩小;厚壁特征和静压载荷形成的附加刚度和附加质量效应降低了球壳耦合共振频率,进而改变了峰值点阻抗特性和水下声辐射幅值特征,在低频段,静压载荷对声辐射峰值的影响更大,而在中高频段,厚壁特征的影响更加突出;对于厚径比h/a>0.05的大壁厚球壳,在无量纲频率Ω>1时,应采用厚壳理论模型开展振动声辐射计算;在极限压力条件下,还应考虑静压载荷对球壳水下声辐射的影响,尤其是对低频峰值特征的影响。

To investigate the vibration and acoustic radiation characteristics of deep submerged spherical shells,a vibro-acoustic coupling model based on thick-shell theory was established,with the shear deformation and rotary inertia effects taken into account.The initial stress field caused by hydrostatic pressure was also considered.Coupled vibration and acoustic radiation of submerged spherical shells under mechanical point excitation were studied.The results show that the coupled vibration response of a thick-walled spherical shell is much smaller than that of a thin-walled spherical shell.However,the difference in underwater acoustic radiation between the two is greatly reduced.The study also reveals that the additional stiffness and additional mass effects,brought by thick-wall feature and hydrostatic pressure,reduce the resonance frequencies of the spherical shell.Furthermore,the impedance characteristics of the submerged spherical shells are affected while the peaks of underwater acoustic radiation are changed.In the low frequency range,the hydrostatic pressure has a greater impact on the acoustic peaks while in the mid-to-high frequency range,the influence of the thick-wall feature is more significant.For spherical shells with thickness-to-radius ratios of over 0.05,the thick shell theory should be used for evaluation of coupled vibration and radiation whenΩ>1.Under extreme pressure conditions,the influence of hydrostatic pressure on the acoustic radiation of the shells,especially on the low frequency peaks,should also be considered.