Isolation & Damping Defined & Differentiated

Prospective buyers of vibration control products should know the basic definitions of, and the distinctions between ISOLATION and DAMPING to enable them to make informed purchases.

ISOLATION refers to the process of preventing (minimizing) externally generated vibratory energy from reaching a structure or component. Although this includes acoustic or air-borne vibration that is difficult to manage in exposed audio/video equipment, we are primarily concerned with the transfer of mechanical vibration. And, it is essential to understand that there is no significant mechanical isolation possible unless there is relative movement between the component and its supporting structure to prevent sympathetic movement with the supporting structure. Therefore, only a device or material that can compress like a spring or deform like an air-bag or a viscoelastic part, or “roll” like a bearing, can be an isolator. Exceptions to these “passive” examples include “active” systems that have electromechanical “self-leveling” capabilities. Obviously, hard “spikes” and (bare) "platforms" or "shelves" are not isolators.

DAMPING is the dissipation of energy in an vibrating structure or component. It refers to the process of removing (minimizing) internally generated vibration that is inherent in a component AND any external vibration that, for lack of adequate isolation, may enter the component, by converting the mechanical vibratory energy of solids into heat energy - a process called hysteresis. Damping is generally accomplished by the bonding of viscoelastic materials to the (vibrating) internal surfaces, mechanisms and parts of a component and by external coupling to viscoelastic materials or damping devices.