ABSTRACT
Damping of a material is defined as “The mechanism by which the energy o f vibration is gradually converted to other form(s) o f energy such as sound, heat, noise,...etc” . The damping type prevailing in pile driving problem is believed to be viscous damping, in which the damping force is proportional to the velocity of the moving body, and the viscous damper is modeled by a piston-cylinder dashpot. The dominating equation o f free motion in a viscous media is:
and the roots o f Eq.(2) are:
where; (c ) is the damping constant, (k) is stiffness, (Q defines the damping ratio as (c/ccr), and (a)n) is the natural frequency.
