Development of a dynamic vibration absorber with adjustment mechanism of spring constant and damping coefficient

Abstract

This paper proposes a simple passive device with an adjustment mechanism for spring constant and damping coefficient to realize a dynamic vibration absorber (DVA) that can be used for various vibration control target frequencies. The proposed device consists of a coil spring and an air spring with an auxiliary reservoir and orifice. The active coil of the device's coil spring can be varied to adjust the spring constant. The main tank and reservoir tank are separated by an "orifice disk" with several orifices of different diameters, and the damping coefficient can be changed by selecting one of these orifices. A numerical model was constructed to design the spring constant and damping coefficient, and a DVA equipped with the proposed adjustment mechanism was developed. The results of stand-alone vibration tests showed that the changing trend of vibration response property agreed well with the numerical results, and the proposed adjustment mechanism worked well. Then, vibration control tests were conducted by mounting a dynamic vibration absorber on a plate-like structure that simulates the underframe of a railroad car at approximately 1/10 scale. As a result, a significant vibration reduction was successfully achieved for the bending mode of elastic vibration, and the usefulness of the proposed spring constant and damping coefficient adjustment mechanism was confirmed by adjusting the optimum spring constant and damping coefficient values, which varied at each measurement point.