Abstract
The vibratory characteristics of multiple nonlinear beams attached to elastic structures under harmonic excitation are investigated. Van del Pol's method is used to determine the resonance curves. It is found that a part of resonance curves, which are stable in a system with one nonlinear beam, change to be unstable and that five branches for steady state solutions may appear. The beams vibrate in different amplitudes. This means "localization phenomena." The system may encounter fold bifurcations and Hopf bifurcations depending on the values of the system parameters. Amplitude modulated motions, including chaotic vibrations, are observed in the numerical simulation.