Analysis of Internal Damping in Rotating Shaft

Abstract

In most of the applications of vibration compared to the elastic and inertia forces, the magnitude of damping forces is small. Under certain circumstances, these small forces may, however, create great influence. Damping is one of the important parameters in the study of dynamic systems. It is generally measured under conditions of cyclic motion and is defined as the energy dissipation in a mechanical system whose free oscillations decrease with time, resulting in a decrease in its amplitude of vibration. From a theoretical point of view, there are two different methods to measure damping, i.e., time response methods and frequency response methods. In rotating machinery, the measurement of damping by applying time response methods and frequency response methods is very difficult. Due to that reason, there is a lack of experiments to measure damping in rotating machinery. This paper discussed Kelvin–Voigt approach for measuring damping in mechanical systems. The mechanical system analyzed in this thesis is a rotating shaft. In general, damping can be explicit through different parameters as damping ratio (ζ) or loss factor (η). Therefore, the objective about this paper is to determine one of these parameters by means of measuring simple variables such as forces or displacements.