Nonlinear normal modes in pendulum systems

Dynamics of the spring pendulum and of the system containing a pendulum absorber is considered by using the nonlinear normal modes’ theory and the asymptotic-numeric procedures. This makes it possible to investigate the pendulum dynamics for both the small and large vibration amplitudes. The vibration modes stability is analyzed by different methods. Regions of the nonlinear normal modes’ stability/instability are obtained. The nonlinear normal modes’ approach and the modified Rauscher method are used to construct forced vibration modes in the system with a pendulum absorber.