A study on dynamic absorber with two pendulums(balls) mounted on tilted vibrating system

在开发一种动力吸振器，由两个阻尼器（垂直：参数激励，水平：共振），这是有效的结构在垂直和水平方向的振动，分析和实验研究进行。还研究了用滚珠（滚子）代替两个滚珠的系统。本文得到了以下结果：1）建立了倾斜单自由度系统在倾斜方向激励下的非线性运动方程; 2）提出了一种使系统总频率响应最小的最佳阻尼比设计方案。数值计算了不同倾角下的最佳阻尼比和相应的频率响应，结果表明双阻尼型动力吸振器具有良好的减振效果。3）建立了考虑滚柱与导轨间滑移的滚柱型动力吸振器倾斜振动系统的运动方程，数值和实验结果表明，滚柱型动力吸振器具有与单摆系统相似的阻尼效果。研究性能的辊型阻尼器的最佳阻尼仍有待测试，由于在实验上放置阻尼机构的辊运动的困难，然而，紧凑的建议系统提供紧凑的实施和良好的性能在固定频率的激励。

On developing a dynamic absorber consisting of two pendulums (vertical : parametrically excited, horizontal : resonated) which is effective for vibration of a structure in both vertical and horizontal directions, analytical and experimental studies are performed. The system where the two pendulums are replaced by balls (rollers) is also investigated. In this study the following results are obtained.1)Nonlinear equation of motion is developed for the tilted single DOF system subjected to excitation in tilted direction.2)A scheme for obtaining the optimum damping ratio is suggested where overall frequency response of the system can be minimized. The optimum damping ratio and corresponding frequency response is calculated numerically for several tilted angle, and the results show that proposed dual pendulum-type dynamic absorber is effective for vibration control. Moreover, the experimental investigation shows good correspondence with numerical tests.3)Equation of motion for the tilted vibration system with roller-type dynamic absorber is developed, where the slip between roller and guide is considered, Both numerical and experimental tests show that the roller type absorber represents similar damping effect as the pendulum system. Investigating performance of roller type damper with optimal damping remains to be tested due to the difficulty in placing damping mechanism for the roller motion experimentally, however, the compactness of the suggested system provides compact implementation and good performance at fixed frequency excitation.