Abstract: In order to catch the characteristic signal of mechanical faults as early and accurately as possible, a new method is introduced to detect weak useful signal buried in noise based on stochastic resonance (SR) theory, Its principle and property are simply illustrated. The detecting model is given and simulated data are analyzed by the model in detail. The model is applied to detect the weak frequency component signals characterizing the inception of rub-impact fault of rotor system. The result shows that this method is simple and reliable. The weak sinusoid signal of lower signal-to-noise ratio can be reliably extracted from heavy noise. The detection approach of weak signal based on SR indicates promising future for mechanical fault diagnosis.

Key words: Mechanical fault diagnosis, Rotor rub-impact, Stochastic resonance, Weak signal detection, Dynamic differential equations, Hardware-in-the-loop simulation, Matlab/Simulink, SMP parallel computation