简化双层底结构振动传递及抑制特性分析

Analysis of the vibration transmission and impediment characteristics of simplified double bottoms

本文运用波分析法研究了简化双层底结构振动能量传递及抑制特性。通过理论计算,对比了不同阻振质量布置的阻振效果;根据多级阻振质量的局限性,提出阻振质量结合阻尼层的复合抑制措施。使用有限元法建立阻抗边界模拟无反射边界对简化模型进行了数值试验,有限元法与解析法结果基本吻合,验证了理论分析的正确性。研究结果表明,内外底板均以弯曲振动为主,底纵桁发生弯曲或纵向共振时,传递至外底板的振动能量最高;复合抑制措施可以达到甚至超过多级阻振质量的阻振效果,并能有效拓宽隔振频带。这为双层底结构振动抑制提供了理论分析和数值试验基础。

Wave approach was used to investigate the characteristics of simplified double bottoms’vibration transmission and impediment.The impeding effect of different blocking mass arrangements was compared by analytical method.According to the limitation of several arranged blocking masses,the composite impeding measurement of combing blocking mass and damping layer is presented.Using impedance to simulate the non-reflection boundary,the simplified model was calculated by FEM.The results of FEM coincided reasonably well with those of analytical prediction,which validated the equations from theoretical analysis.It is found that the vibration mode in both bottoms is flexural and the vibration energy transmited to the outer bottom reaches its maximum when the flexural or longitudinal resonance occurs in the bottom girder.Composite impeding measurement can not only cause as much transmission loss as that of several arranged blocking masses,but also widen the frequency band of vibration impediment.The study provides a theoretical analysis and numerical experiment basis for the vibration impediment of double bottoms.