颗粒阻尼器受迫振动减振耗能机理及试验研究

Mechanism and experimental study of energy dissipation caused by forced vibration of particle damper

颗粒阻尼器在船舶减振降噪领域起到了良好的宽频吸振作用。为了进一步实现对颗粒阻尼器的设计和使用,文中探究了颗粒阻尼器内部颗粒的碰撞耗能机理,结合工程实际,开展了颗粒碰撞耗能、碰撞热耗能和碰撞声耗能的耗能研究。对颗粒体的受迫振动碰撞耗能进行试验,通过对颗粒体受迫振动呈现的“气-液-固”三态的研究,发现颗粒内部和颗粒与容器壁碰撞发生的能量转移是颗粒体能量耗散的原因。基于离散单元法,研究了颗粒简谐振动的频率、幅值及填充率对颗粒耗能特性的影响规律,颗粒体对振动的频率有较高的敏感性,当颗粒振动频率在低频时,耗能较大;当颗粒振动频率逐渐向高频变化时,颗粒振动的耗能减小。当颗粒的填充率接近100%时,颗粒之间的碰撞并不充分,耗能减小;当颗粒填充率在90%左右时,耗能效果较好。对颗粒体在类固态和类液态状态下的热耗能进行分析,颗粒总体呈上升到稳定的趋势,不同状态颗粒稳定时间和上升温差不同。对颗粒体声耗能进行了试验研究,当颗粒处于高频振动时碰撞耗能减小,其中一种形式即转化为声耗能,且激振频率越高,声耗能越明显。该研究为颗粒阻尼器在实际工程中的应用和优化设计提供了理论参考。设计了一种减振系统试验台架,并在台架模态位置处安装颗粒阻尼器进行模态控制试验。颗粒阻尼器在10~200 Hz内有5根线谱明显降低,最大降幅可达25 dB,具有明显的吸振效果。结果表明:采用不同的模态控制方式,可以实现对不同频率加速度级的有效控制。

Particle dampers have good effect of broadband vibration absorption in terms of ship vibration and noise reduc-tion.In this article,in order to ensure that the particle damper is designed and used properly,efforts are made to explore the particles'mechanism of collision energy dissipation in the particle damper.In combination with the engineering practice,the a-nalysis is conducted on the particles'collision energy dissipation,collision thermal energy dissipation and collision acoustic en-ergy dissipation.Firstly,the experiment is carried out on the collision energy dissipation caused by the particles'forced vibra-tion;according to the study on the particles'three phases of gas-liquid-solid caused by the forced vibration,it is found that the energy transfer among the particles and in the process of the particles colliding with the container wall is responsible for the energy dissipation.With the help of the discrete element method,efforts are made to explore the effects of frequency,amplitude and filling rate of the particles'harmonic vibration on the energy-dissipation characteristics.The particles have high sensitivity to the vibration frequency.The energy dissipation caused by the particles'vibration is larger when the vibration frequency is low;the energy dissipation decreases with the vibration frequency gradually moving to a higher level.When the particles'filling rate approaches 100%,the collision among the particles is not sufficient and the energy dissipation reduces.When the filling rate is around 90%,the particles have good energy-dissipation effect.Besides,the analysis is carried out on the particles'thermal energy dissipation in the solid-like and liquid-like states.The particles generally show a trend of rising to stability;the stability time and the rising temperature difference in different states are various.Next,the experimental study is conducted on the particles'acoustic energy dissipation.When the particles are in the high-frequency vibration,the collision energy dissipation decreases,and part of the collision energy dissipation is converted into the acoustic energy dissipation.The higher the excitation frequency is,the more obvious the acoustic energy dissipation will be.This study provides theoretical reference for application and optimal design of particle dampers in the engineering practice.In addition,a test bench for the vibration-reduction system is designed,and a particle damper is installed at the test bench's modal position,so as to carry out the modal control experiment.The particle damper has obvious reduction in 5 lines at 10~200 Hz,with the maximum of 25 dB,which has good vibration-absorption effect.It is shown that the acceleration stages of different frequencies can be effectively controlled by adopting different methods of modal control.