A non-obstructive particle damping model of DEM
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A non-obstructive particle damping model of DEM Li Hu Æ Qibai Huang Æ Zhanxin Liu
Received: 28 July 2007 / Accepted: 26 November 2007 / Published online: 6 December 2007 Springer Science+Business Media B.V. 2007
Abstract The non-obstructive particle damping technology has been used successfully in many fields for vibration reduction. However, it is difficult to predict the damping characteristics due to complex collisions in the dense particle flow. The discrete element method makes it possible to consider effects of granularity such as the particle size, number of particles and friction between two particles. The validity of this numerical method is examined by a comparison of the experimental results. The discrete element method simulation system is further examined with examples for its computational complexity and effectiveness for different density parameters. It is shown that the mass ratio and material density influence the damping performance. Keywords Non-obstructive particle damping Discrete element method Vibration suppression
1 Introduction Non-obstructive particle damping (NOPD) technology is a derivative of impact damping with several advantages. Impact damping usually refers to only a
L. Hu (&) Q. B. Huang Z. X. Liu School of Mechanical Science & Engineering, Huazhong University of Science & Technology, Wuhan Hubei 430074, P.R. China e-mail: [email protected]
single (somewhat larger) auxiliary mass in a cavity, whereas non-obstructive particle damping is used to imply particles of various shapes, sizes, and materials in an enclosure attached to a structure. As a result of the collisions, momentum is exchanged between the structure and the particles, and kinetic energy is converted to heat. Additional energy dissipation can also occur due to particle-to-particle collisions and frictions and particle-to-wall frictions. The unique aspect of NOPD is that high damping is achieved by absorbing the kinetic energy of the structure as opposed to the more traditional methods of damping where the elastic strain energy stored in the structure is converted to heat. Non-obstructive particle damping offers the potential for the design of an extremely robust passive damping technique with minimal impact on the strength, stiffness and weight of a structure over wide temperature ranges. Studies conducted over recent years have demonstrated the effectiveness and potential application of particle dampers to reduce vibration in a space shuttle main engine liquid oxygen inlet tee (Panossian 1992) and to attenuate the resonant vibrations of antennae (Simonian 1995). Papalou and Masri (1996) studied the behavior of non-obstructive particle dampers in a horizontally vibrating single-degree-of-freedom (s.d.o.f.) system under random excitation. They studied the influence of mass ratio, particle size, container box dimensions, excitation levels, and direction of excitation. Damper container design criteria were provided for optimal efficiency based
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upon reduction in system response. Panossian (1991b)
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