两尺度Duffing系统的动力吸振器减振研究
STUDY ON VIBRATION REDUCTION OF DYNAMIC VIBRATION ABSORBER FOR TWO-SCALE DUFFING SYSTEM
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摘要: 两尺度耦合的Duffing系统存在复杂振动, 此类振动具有振幅大、频率高的特点, 对系统的危害不容忽视. 研究了线性动力吸振器对低频参数激励下Duffing系统的振动控制问题, 通过对比耦合动力吸振器前后系统的时间历程图、相图, 发现加入动力吸振器后系统会由单一振动模式转变为混合振动模式(簇发振动), 振动幅值明显减小, 尤其对高频振动部分抑制明显. 利用快慢分析法, 当参数激励为慢变过程时得到相应的自治系统, 并发现自治系统稳定性与分岔行为对非自治系统振动响应具有明显调节作用. 研究结果表明, 虽然耦合动力吸振器前后自治系统均发生叉形分岔, 但是加入吸振器后自治系统稳定性发生变化, 稳定中心变为渐进稳定的焦点, 稳定平衡线对非自治系统轨线的吸引力增强, 使得响应振动幅值减小; 另外轨线在不同吸引子之间的跳跃次数减少, 也是导致响应振动幅值减小的另一个原因. 通过对参数激励的相关参数减振效果分析, 发现加入的动力吸振器在较大的振动幅值和频率范围内都能起到抑制系统振动的作用. 为两尺度系统耦合线性动力吸振器减振研究提供了理论依据.Abstract: Duffing system with two-scale coupling generally will behave in complex vibration, because of the characteristics of large amplitude and high frequency, then the harm from complex vibration cannot be ignored. The vibration control problem of linear vibration absorber for Duffing system with low frequency parameter excitation is studied. By comparing the time history diagram and phase diagram of the system before and after coupling the linear dynamic vibration absorber, the system with dynamic vibration absorber shows mixed vibration mode (bursting vibration), and the vibration amplitude is suppressed significantly, especially for the high frequency vibration part. Using the slow-fast analysis method, the corresponding autonomous system is obtained when the parameter excitation is a slowly varying process. It is found that the stability and bifurcation behavior of the autonomous system can obviously regulate the vibration response of the non-autonomous system. The results show that although fork bifurcation occurs in the autonomous system before and after the coupled dynamic vibration absorber, the stability of the autonomous system changes after the dynamic vibration absorber is added. Comparing to the stable center in the original system, the attractor of the autonomous system coupled linear dynamic vibration absorber changes to asymptotically stable focus. The attractive force of the stable equilibrium line of autonomous system to trajectory of non-autonomous system is enhanced, which reduces the vibration amplitude of the non-autonomous system. In addition, the reduction about hops times of trajectory between different attractors is another reason for the decrease of the vibration amplitude. Based on the analysis of vibration reduction effect with relevant parameters of parametric excitation, it is found that the dynamic vibration absorber can suppress the vibration of the system in a large vibration amplitude and frequency range. It provides a theoretical basis for the research on vibration reduction of two-scale system coupled linear dynamic vibration absorber.