On Mode Dependency of Damping Ratio in Material Damping

Abstract

In turbo-machineries, there exist the vibration problems that the blades which are most important parts are broken. Many of them are due to the resonance. When the resonance occurs once it is obliged to stop the operation of the factory. Therefore, it is desired that the blade does not break even if in the resonance. The author has been studied the vibration problems of blades for many years. In these studies, it would like to be known that the damping ratio of the first vibration mode is the same as these of higher modes. If the damping ratio is independent of the vibration mode all we have to do is to evaluate only the damping ratio of the first mode. Then in this study, it will be discussed that whether the damping ratio is dependent on the vibration mode or not.