Abstract
To attain optimum design of vibration cotrollers to suppress many resonance peaks of machine structures, it is necessary to know the equivalent mass at the mounting location of the controller. This paper shows two ways for estimating the equivalent mass : one is the modal analysis method, and the other is called the mass responsive method, which utilizes the variation of the natural frequency of the structure when an additional mass is attached. The first method mentioned is useful to identify modal mass having "physical meaning", while the other method is most suitable for application in the experimental analysis. The accuracy of these methods are compared with each other by applying them to three kinds of mechanical structure.
