Numerical study of Coulomb and viscos damping

Abstract

Mechanical vibration damping is broadly classified into viscous and coulomb damping. The objec-tive of the thesis was to study response and characteristic parameters of the vibration damping such as decay factor, resonant frequency, and quality factor. These factors play crucial role in designing and operation of machines. Vibration response and quality factor i.e. 2p times ratio of total energy to damping capacity of viscous, coulomb and combine damping is studied using SCILAB and fast Fourier transform technique is applied to determine the natural frequency of the system. The gov-erning equations are simulated for time response and its Fast Fourier transform FFT is plotted to get the quality factor. Study shows that the quality factor for viscous damped system is lesser than the coulomb damped system. Analysis of the combine damped system shows the dominance of viscous damping in a system as compare to the coulomb damping. This is because viscous damping has greater damping ratio than coulomb damping. The response of combine damped system show the dominance of the viscous damping in damping the system vibration. A sine wave was achieved with the decay curve resembling closely to the overdamped system.