Abstract: The analysis of dynamic system with many degrees of freedom can be highly complex in the presence of strong nonlinearities, but it is important to understand the mechanisms of some phenomena The fundamental response of a nonlinear nonautonomous system is periodic, other motions, such as quasi-periodic, jump, period-doubling and chaotic motion, can bifurcate from periodic motion when a system parameter is changed Therefore, determining the periodic solution and its stability are required in such case ...