Effect of Coulomb Friction on the Forced Vibration of a System with Elastically Supported Viscous Damper

Abstract

The analysis on the forced vibration of a system with elastically supported viscous damper whose damping is accompanied by the Coulomb friction is a very complicated one, for the reason that its every cycle is composed of two different kinds of motions and that seven boundary conditions are needed to solve it. In this paper, the author presents certain characters of the vibration of a system with optimum damping and Coulomb friction, the calculation of which is carried out by a digital computer. It became clear from the results of the analysis and the experiments that, while the Coulomb friction is smaller than the disturbing force, the amplitude seems to grow larger continuously from infinite damping curve to the optimum damping one as the frequency increases, but in the case where the friction overcomes the disturbing force, a jumping phenomenon of the amplitude occurs at a fixed place corresponding to the amount of friction.