舰船科学技术  2017, Vol. 39 Issue (2): 70-74 PDF

Effect on cylindrical shell structural vibration and acoustic radiation due to rubbers laying on pipeline
LIU Fan, ZHOU Qi-dou, LV Xiao-jun
Naval University of Engineering, Wuhan 430033, China
Abstract: A method called structural finite element coupled with fluid boundary element was adopted to calculate the underwater vibration and acoustic characters from a cylindrical shell including a pipeline was affected by the pipeline that surrounded by rubbers different in thickness. The effect of rubbers on the cylindrical shell underwater vibration and acoustic radiation was analyzed from vibration displacement and radiation noise of the cylindrical shell. This provides references for designing acoustic configuration of a underwater structure. The calculation showed that the pipeline surrounded by rubbers different in thickness also decreased the cylindrical shell's underwater radiation noise and vibration for this calculate example. And the thicker rubbers are, the more structural vibration and acoustic radiation are reduced.
Key words: cylindrical shell     pipeline     vibration     acoustic field     rubber layer
0 引 言

1 结构有限元耦合流体边界元算法

 $\left[ {{\mathit{\boldsymbol{K}}}_{s}}-{{\omega }^{2}}{{\mathit{\boldsymbol{M}}}_{s}}-i\omega {{\mathit{\boldsymbol{N}}}_{s}} \right]\mathit{\boldsymbol{a}}=\mathit{\boldsymbol{F}}+{{\mathit{\boldsymbol{F}}}_{\rm{out}}},\text{，}$ (1)

 ${{\mathit{\boldsymbol{F}}}_{out}} = \left[ { - \left( { - {\omega ^2}{\mathit{\boldsymbol{ M}}}} \right) - \left( { - {\mathit{\boldsymbol{i}}}\omega {\mathit{\boldsymbol{ N}}}} \right)} \right]{\mathit{\boldsymbol{a}}}\text{，}$ (2)

 $\left[ {{{\mathit{\boldsymbol{ K}}}_s} - {\omega ^2}({{\mathit{\boldsymbol{ M}}}_s} + {\mathit{\boldsymbol{ M}}}) - {\mathit{\boldsymbol{i}}}\omega ({{\mathit{\boldsymbol{ N}}}_s} + {\mathit{\boldsymbol{ N}}})} \right]{\mathit{\boldsymbol{a}}} = {\mathit{\boldsymbol{F}}}\text{，}$ (3)

 $W = \frac{1}{2}Re\{ i\omega \sum\limits_{j = 1}^{{m_e}} {{p_j}\delta _j^*{S_j}} \} \text{，}$ (4)
 $< \overline {{V^2}} > = \frac{{{\omega ^2}\sum\limits_{j = 1}^{{m_e}} {\left| {{\delta _j}} \right|{S_{\rm{j}}}} }}{{\sum\limits_{j = 1}^{{m_e}} {{S_{\rm{j}}}} }} \text{，}$ (5)

 ${L_W} = 10\lg \frac{W}{{{W_{ref}}}}\text{，}$ (6)
 ${L_{\bar V}} = 10\lg \frac{{ < {{\bar V}^2} > }}{{V_{ref}^2}}\text{。}$ (7)

2 几何模型及有限元建模

 图 1 圆柱壳与管路基本结构 Fig. 1 Fundamental structure of the cylindrical shell and pipeline

 图 2 圆柱壳体在水下的位置 Fig. 2 Location of underwater cylindrical shell

 图 3 结构有限元模型剖面图 Fig. 3 Structural FE model profile

3 数值计算及结果比较分析

 图 4 圆柱壳湿表面均方法向速度级频响曲线 Fig. 4 Mean-square normal velocity level frequency response curves of cylindrical shell wetted surface

 图 5 圆柱壳湿表面辐射声功率级频响曲线 Fig. 5 Radiated acoustic power level frequency response curves of cylindrical shell wetted surface

 图 6 圆柱壳湿表面位移云图 Fig. 6 Displacement coutours of cylindrical shell wetted surface

 图 7 圆柱壳辐射声场声压级云图 Fig. 7 Radiated pressure coutours of acoustic filed out of cylindrical shell

4 结 语

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