Abstract
Intrinsic Localized Modes (ILMs) are investigated in a mechanical system where N pendula are connected with each other by week linear springs when this system is subjected to horizontal excitation. The purpose of this study is to resolve the dynamical mechanism and the behavior of ILMs. In the theoretical analysis, the equations of motion for the system are derived and then van der Pol's method is employed to determine the expression for the frequency response curves. In the numerical calculation, the frequency response curves are shown for the cases of N=2 and 3 and compared with the results of the numerical simulation. Patterns of oscillations are classified from the results of the response curves, and it is found in which pattern ILMs appear. The influence of the spring constants of the connecting springs on the occurrence of the ILMs is examined. The change of the values of those spring constants may cause to Hopf bifurcation followed by amplitude modulated motion.
