Experimental and numerical investigations on the performance of particle dampers attached to a primary structure undergoing free vibration in the horizontal and vertical directions

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• 作者：Yanrong Wang^a ; ^b ; ^{yrwang@buaa.edu.cn" class="auth_mail" title="E-mail the corresponding author} ; Bin Liu^a ; ^b ; ^{buaa_LiuB@163.com" class="auth_mail" title="E-mail the corresponding author} ; Aimei Tian^c ; ^{amtian@buaa.edu.cn" class="auth_mail" title="E-mail the corresponding author} ; Wei Tang^d ; ^{tw_capebz@126.com" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Particle damping ; Horizontal&ndash ; vertical excitations ; Free vibration ; Discrete element method
• 刊名：Journal of Sound and Vibration
• 出版年：2016
• 出版时间：9 June 2016
• 年：2016
• 卷：371
• 期：Complete
• 页码：35-55
• 全文大小：5539 K

文摘

Particle damping (PD) has been well known for its simplicity and high efficiency in attenuating structure vibration. Recent studies on PD have focused mainly on new types of dampers and applications. Meanwhile, excitation applied to the primary structure is still limited to either horizontal or vertical direction, perpendicular or parallel to gravity. In this study, the characteristics of PD under horizontal–vertical excitations (HVE) are investigated numerically and experimentally. The particle damper, which is attached to the top free end of an L-shaped cantilever beam, is simultaneously excited in the horizontal and vertical directions in the context of free decay. An equivalent model capable of motion in both the horizontal and vertical directions is generated. Given an initial displacement disturbance, this model starts vibrating freely in the vertical plane. A code based on the 3D discrete element method is programmed, and the high coincidence between the numerical and experimental results shows that this equivalent model is capable of high-fidelity simulation for PD under HVE.

Parametric studies have been implemented to characterize the basic nonlinear damping capacity of particle dampers under this new operating condition. The effects of seven dimensionless independent parameters on the specific damping capacity (SDC) are investigated, including dimensionless acceleration amplitude, particle mass ratio, dimensionless horizontal and vertical impact clearances, coefficients of friction and restitution, and amplitude ratio of the horizontal excitation to the vertical excitation. The results show that the basic damping properties of PD under HVE are similar to those of PD under only vertical excitation. However, PD under HVE signifies its own characteristics because of the existence of horizontal excitation: (1) The impact clearances in both the horizontal and vertical directions have significant effects on the SDC because of the significant increase in oblique impacts. (2) The shape and dimensions of a damper cavity should be designed according to the acceleration amplitude. If the amplitude is relatively low (such as Γ<3 in this study), the optimum shape of the damper cavity tends to be flat. By contrast, if the amplitude is high (such as Γ close to 10), the optimum shape tends to be elongated. The damping differences between PD under HVE and vertical excitation are also investigated. For PD under HVE, the kinetic energy is mainly dissipated by friction rather than inelastic collision for PD under vertical excitation. In addition, by use of different amplitude ratios of the horizontal excitation to the vertical excitation, it is found that the total ratio of energy dissipation for the particle dampers under HVE generally becomes higher, and the optimum Γ region for high SDC is also expanded.