TABLE OF CONTENTS The term damping as used in this chapter refers to the energy-dissipation properties of a material or system under cyclic stress, but excludes energy-transfer devices such as dynamic absorbers. With this understanding of the meaning of the word, energy must be dissipated within the vibrating system. In most cases a conversion of mechanical energy to heat occurs. For convenience, damping is classified here as (1) material damping and (2) system damping. Material properties and the principles underlying the measurement and prediction of damping magnitude are discussed in this chapter. For application to specific engineering problems, see Chap. 37.
Without a source of external energy, no real mechanical system maintains an undiminished amplitude of vibration. Material damping is a name for the complex physical effects that convert kinetic and strain energy in a vibrating mechanical system consisting of a volume of macrocontinuous (solid) matter into heat. Studies of material damping are employed in solid-state physics as guides to the internal structure of solids. The damping capacity of materials is also a significant property in the design of structures and mechanical devices; for example, in problems involving mechanical resonance and fatigue, shaft whirl, instrument hysteresis, and heating under cyclic stress. Three types of material that have been studied in detail are:
Viscoelastic materials. [1] The idealized linear behavior generally assumed for this class of materials is amenable to the laws of superposition and other conventional rheological treatments including model analog analysis. In...
