Abstract: A metal rubber-steel wire shimmy damper of helicopter rotor is developed. Firstly, the bilinear hysteresis model with non-symmetry elastic storing forces and viscous damping is established refering to the force-displacement hysteresis curve of the shimmy damper. At the same time the nonlinear model is linearized by the Fourier series expansion. Secondly, the separating-parameter identification arithmetic is presented based on the geometrical symmetry relationship of each restoring force component in the force-displacement hysteresis curve. To prove the credibility of the separating-parameter identification arithmetic, a bilinear hysteretic simulation element with non-symmetry cubicre elastic storing forces and viscous damping is established. Simulation result shows that the arithmetic has high fitting accuracy and noise proof feature. Finally, when the shimmy damper system is excited by the sine displacement load whose amplitude is 3.2 mm and frequency is 3 Hz, the calculation results show that the model and identification arithmetic can be used in practical application.

Key words: nonlinear vibration, shimmy damper, metal rubber, hysteretic vibration system modeling