Application of a Stochastic Version of the Restoring Force Surface Method to Identify a Duffing Oscillator

Abstract

A stochastic version of the restoring force surface method is proposed and used to identify the parameters of a clamped-free beam with nonlinear effects induced by the presence of a magnet near to the free extremity. This system recalls a Duffing oscillator, which is used as a single-degree-of-freedom mathematical model to represent the mechanical system. Experimental and theoretical responses are compared taking into account a probabilistic band of confidence. The results show that the stochastic model identified can predict the beam's vibration responses, which ensure the robustness of the stochastic identification method.