Abstract
Damping ratio which shows damping of the vibration system composed of loading mass added on spring and dashpot is the importance, when it is designed in vibration isolation. Half-power method is used in order to identify damping ratio using resonance curve of forced vibration. Half-power method is an approximation calculated from the approximate analysis result using natural angular frequency. And, it is known that the error increases, when damping ratio consists over 0.1. The development of various high damping vibration proofing material advances recently, and the derivation of exact equation which can be applied to the case with big damping ratio is desired. This study proposes method to derive of exact equation of damping ratio. Then, it was rewritten in resonance curve which described resonance curve using natural angular frequency in the peak angular frequency, and exact equation of half-power point was required from this resonance curve, and exact equation of damping ratio was calculated. In addition, the relation between error and exact equation of damping ratio estimated equation by half-power method is explained in detail.
