Abstract
There are a lot of nonlinear phenomena in the world, and it is confirmed that the chaos is contained in the nonlinear vibration. In this study, the vibration model, which mechanical spring is set on perpendicular to the moving direction, has been proposed. This model is described by initial length of spring, slope of spring, mass, damping constant, spring constant. The governing equation of this model is non-linear such as Duffing equation, and has been found to have chaotic motion. The effect of km, whlch is the nonlinear elastic force, on the motion of the system has been investigated by the bifurcation diagram, the time series. Poincare map, Lyapnov exponent and power spectra.