阻隔质量对杆类结构弯曲波隔离的工程应用研究

阻隔质量是结构噪声控制的一项重要技术。从波传播的研究出发,推导了具有阻隔质量的无限长杆类结构中弯曲波的无量纲化传递损失公式,分析了阻隔质量对弯曲波的传递损失特性。开展了阻隔质量技术对杆类结构弯曲波隔离的工程应用研究。理论分析表明,在阻隔质量技术对弯曲波隔离的工程应用中,传递损失主要与三个参量有关:阻隔质量的大小及其回转半径和杆的回转半径。为了提高弯曲波的传递损失,在容许的限制条件下,原则上应尽量增加阻隔质量块的大小和回转半径。如果杆件能够选择,减小杆件的回转半径也是改善弯曲波传递损失的一个有效措施。

Application of transmission loss for flexural wave of infinite rod with blocked mass

Based on wave propagation,formulations of transmission loss for flexural wave of an infinite rod with a blocked mass are derived.Characteristics of transmission loss for flexural wave of an infinite rod with a blocked mass are analyzed.Theoretical results show that transmission loss for flexural wave does not exceed 3dB when the blocked mass is only considered as a pure point mass.When the blocked mass is regarded as pure moment of inertia,there exists a particular frequency at which the blocked mass can completely impede the flexural wave propagation.At very high frequencies,transmission loss is approximately 3dB.When the blocked mass is considered as both mass and moment of inertia,transmission loss may be greatly improved.In applications,tran-smission loss is relevant to three parameters: magnitude,radius of gyration of the mass,and radius of gyration of the rod.In principle,increasing magnitude and radius of gyration of the mass can improve transmission loss within engineering limits.If the rod is selected,decreasing the radius of gyration is also an effective way to improve transmission loss.