Theory of Vibration Isolation of a System with Two Degrees of Freedom : 1st Report, Motion Excitation

Abstract

This paper deals with a theory of vibration isolation of a two-degree-of-freedom system subjected to a harmonic motion. The system is made up of two subsystems each having a one degree of freedom. The first subsystem consists of a mass m1 connected to a foundation in motion through a spring of scale k1 and a dashpot of damping coefficient c1 placed in parallel. The second one contains a mass m2. a spring k2 and a dashpot c2, and is attached to the mass m1 in the same manner. In a special case of c1=0. the optimum tuning and damping of a dynamic absorber (m2-k2 ) have already been studied by Den Hartog et al. However the problem to be studied on the system having two dashpots c1 and c2 is still left unsettled. We searched for the optimum suspension of vibration isolation regarding the mass m1 or m2 of the system mentioned above.