ABSTRACT
The process by which vibrations decrease in amplitude with time is called damping. Damping dissipates the energy of a vibrating system and can do this in a number of ways. There are several different types of damping: friction, hysteretic and viscous. For structural systems the damping encountered is best described using a viscous model in which the damping force is proportional to its velocity. The damping ratio ξ is expressed as a fraction of critical damping and is often written as a percentage (i.e. 1 per cent critical).
