TABLE OF CONTENTS Vibration isolation concerns means to bring about a reduction in a vibratory effect. A vibration isolator in its most elementary form may be considered as a resilient member connecting the equipment and foundation. The function of an isolator is to reduce the magnitude of motion transmitted from a vibrating foundation to the equipment or to reduce the magnitude of force transmitted from the equipment to its foundation.
The concept of vibration isolation is illustrated by consideration of the single degree-of-freedom system illustrated in Fig. 30.1. This system consists of a rigid body representing an equipment connected to a foundation by an isolator having resilience and energy-dissipating means; it is unidirectional in that the body is constrained to move only in vertical translation. The performance of the isolator may be evaluated by the following characteristics of the response of the equipment-isolator system of Fig. 30.1 to steady-state sinusoidal vibration:
Absolute transmissibility. Transmissibility is a measure of the reduction of transmitted force or motion afforded by an isolator. If the source of vibration is an oscillating motion of the foundation (motion excitation), transmissibility is the...
