In steady state response,the energy input to the system due to the applied force is dissipated in viscous damping E,=Sp()du=p(t)idr (po sin )[ou cos(di sm28风-28） uo Po/k 目 土本之相学院• In steady state response, the energy input to the system due to the applied force is dissipated in viscous damping         2 / 0 2 / 0 0 0 2 0 0 0 sin cos sin 2 I n E p t du p t udt p t u t dt p u ku                                 0 0 sin 2 2 / d n n u R p k                     