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In many vibration isolation problems, translational motion has been regarded as a major contributor to the energy transmitted from a source to a receiver. However, the rotational components of isolation paths must be incorporated as the frequency range of interest increases. This article focuses on the flexural motion of an elastomeric isolator but the longitudinal motion is also considered. In this study, the isolator is modeled using the Timoshenko beam theory (flexural motion) and the wave equation (longitudinal motion), and linear, time-invariant system assumption is made throughout this study. Two different frequency response characteristics of an elastomeric isolator are predicted by the Timoshenko beam theory and are compared with its subsets. A rigid body is employed for the source and the receiver is modeled using two alternate formulations: an infinite beam and then a finite beam. Power transmission efficiency concept is employed to quantify the isolation achieved.

The knowledge of frequency-dependent dynamic stiffnesses of mounts, in axial and flexural motions, is needed to determine the behavior of many automotive sub-systems. Consequently, characterization and modeling of vibration isolators is increasingly becoming more important in mid and high frequency regimes where very few methods are known to exist. This paper critically examines some of the approximate identification methods that have been proposed in the literature. Then we present a new experimental identification method that yields frequency-dependent multi-dimensional dynamic stiffnesses of an isolator. The scope is however limited to a linear time-invariant system and our analysis is restricted to the frequency domain. The new characterization method uses two inertial elements at both ends of an isolator and free boundary conditions are maintained during testing.