Vibration Control Using a Dynamic Vibration Absorber with Air Damping

推导了两种空气阻尼器的设计表达式，即粘性空气阻尼器和非粘性空气阻尼器。这些空气阻尼器适用于动力吸振器（DVA），因为它们可以提供大量的阻尼，而不使用高粘性流体。空气阻尼器的活塞在气缸内振动，活塞作为DVA的质量，活塞的动能转化为热量并散发到周围环境中。除了阻尼力之外，活塞还接收恢复力。因此，很难找到空气阻尼DVA的最佳调谐和阻尼条件。提出了计算DVA最佳调谐条件的简单表达式，并通过数值分析得到了DVA的最佳阻尼条件。本报告提供了分析所需的方程式。我们在试验的基础上制作了一个最佳调谐和阻尼的空气阻尼DVA，并附在振动系统上。据观察，系统的振动幅度降低到只有1%。根据我们的研究，理论计算可以比较准确地估计DVA对原系统的影响。然而，这项研究还没有完成，DVA的实际应用还存在许多问题。我们将继续我们的研究，直到我们开发出一个程序，系统地设计最佳调谐和阻尼DVA与空气阻尼。

The expressions for design of two types of air dampers are developed, which are called viscous air damper and non-viscous air damper. These air dampers are suitable for the dynamic vibration absorber (DVA), because they can supply the large amount of damping without using high-viscous fluids. The piston of the air damper vibrating in the cylinder functions as a mass of DVA,and the kinetic energy of the piston is transformed into the heat and dissipated to the surroundings. The piston receives a restoring force in addition to the damping force. Thus, it is very difficult to find the optimum tuning and damping conditions of DVA with air damping. We propose simple expressions to calculate the optimum tuning condition of DVA.The optimum damping condition of DVA is obtained by the numerical analysis. The equations required in the analysis are supplied in this report. We made an optimally tuned and damped DVA with air damping on the trial basis, and attached to a vibratory system. It was observed that the vibration amplitude of the system is reduced to only 1 percent. According to our study, the effect of DVA on the primary system can be estimated fairly accurately by the theoretical calculation. This study is not finished, however, and there are many proplems to make the DVA fit for the practical use. We shall continue our study until we develop a procedure to design systematically the optimally tuned and damped DVA with air damping.