摘要
声黑洞(acoustic black hole, ABH)效应是基于弯曲波在变厚度薄壁结构中的传播性质发展起来的一种被动减振技术.本文针对传统的线性声黑洞在高频段具有显著减振效果,而在低频段减振性能欠佳的问题,利用接触非线性提出了将能量从低频段传递到高频段的想法,旨在提升声黑洞的总体性能.考虑声黑洞梁和位于其下方的接触挡板的碰撞振动问题,首先,通过实验验证了引入接触碰撞后系统的非线性机制及能量传递效应.随后,基于欧拉-伯努利梁理论建立了声黑洞梁和挡板碰撞振动的数值模型,并分析了模型的收敛性.该模型遵循模态法的求解过程,并利用有限差分法处理变厚度梁的特征值问题.接触作用力借鉴于Hertzian接触定律来刻画,阻尼层的影响则通过Ross-Kerwin-Ungard模型求解.基于数值模型,着重分析了含接触非线性时,声黑洞梁的能量传递与衰减特性及其对声黑洞减振性能的提升,并考察了接触刚度、接触点位置和初始间隙等接触参数的影响.结果表明引入接触非线性后,振动能量可以从声黑洞性能欠佳的低频段传递到声黑洞效果显著的高频区域,梁的能量衰减速度显著加快,声黑洞的整体减振性能得到了有效地提高.
Acoustic black hole effect (ABH) refers to a passive vibration mitigation technique which takes advantage of flexural wave properties in thin structures with variable thickness. Focusing on the problem that the classical linear ABH is efficient only at high frequency range but less than desirable in the low frequency domain, this paper proposes the idea of using contact nonlinearity to transfer the energy from low to high frequency range, in order to improve the overall efficacy of the ABH. Considering the vibration of an ABH beam in contact with a rigid barrier from below it, an experimental study is firstly carried out to show the nonlinear phenomena and energy transfer induced by the contact nonlinearity. Then, a numerical model is derived from Euler-Bernoulli beam theory, with convergence properties studied. The model follows the general procedures of modal approach, while the eigenvalue problems are computed using a finite difference method due to thickness variation. The contact force is handled by Hertzian contact law, and the damping layer is dealt with a Ross-Kerwin-Ungard model. Detailed studies considering contact nonlinearity are thus conducted to precisely quantify the energy transfer and decay, and the gain in efficiency of the ABH, with parametric effect respect to the contact stiffness, initial gap and longitudinal location of contact points. It is demonstrated that when the contact nonlinearity is induced to the system, the vibrational energy can be transferred from the low frequency band-where the ABH is inefficient, to the high frequency range-where the ABH is effective, the energy decay in the beam is remarkably accelerated, and the overall performance of the ABH effect is significantly improved.
作者
李海勤
孔宪仁
刘源
Li Haiqin;Kong Xianren;Liu Yuan(Research Center of Satellite Technology, Harbin Institute of Technology,Harbin 150001, China)
出处
《力学学报》
EI
CSCD
北大核心
2019年第4期1189-1201,共13页
Chinese Journal of Theoretical and Applied Mechanics
基金
国家自然科学基金资助项目(51875119)
关键词
声黑洞
阻尼
振动抑制
能量传递
接触非线性
acoustic black hole
damping
vibration suppression
energy transfer
contact nonlinearity