TABLE OF CONTENTS This chapter presents an analytical treatment of the isolation of shock. Two classes of shock are considered: (1) shock characterized by motion of a support or foundation where a shock isolator reduces the severity of the shock experienced by equipment mounted on the support and (2) shock characterized by forces applied to or originating within a machine where a shock isolator reduces the severity of shock experienced by the support. In the simplified concept of shock isolation, the equipment and support are considered rigid bodies, and the effectiveness of the isolator is measured by the forces transmitted through the isolator (resulting in acceleration of equipment if assumed rigid) and by the deflection of the isolator. Linear isolators, both damped and undamped, together with isolators having special types of nonlinear elasticity are considered. When the equipment or floor is not rigid, the deflection of nonrigid members is significant in evaluating the effectiveness of isolators. Analyses of shock isolation are included which consider the response of nonrigid components of the equipment and floor.
In the application of shock isolators to actual equipments, the locations of the isolators are determined largely by practical mechanical considerations. In general, this results in types of nonsymmetry and coupled modes not well adapted to analysis by simple means. It is convenient in the design of shock isolators to idealize the system to a hypothetical one having symmetry and uncoupled modes of motion.
The first step in idealizing...
