Dynamic analysis of the dual-rotor system considering the defect size uncertainty of the inter-shaft bearin.

In this paper, the stochastic dynamic analysis of a dual-rotor system with a local defect on the inner raceway of the inter-shaft bearing is presented. The dynamic model of the dual-rotor system is also proposed. The defect size and its uncertainty are considered. The non-intrusive polynomial chaos expansion model is utilized to deal with the uncertainty of the defect size, and the validity of the model is verified. The probability density distribution of vibration displacements for the dual-rotor system is obtained. Results indicate that the mean value (MV) and standard deviation (SD) of the defect edge length have extremely significant effects on the displacement distribution of high-pressure rotor. The coefficients of variation of the displacements along x2 and ϕx directions for high-pressure rotor increase by 6.56 and 7.06 times, respectively. When the MV of the defect edge length increases by three times, 3.46 times, and 3.69 times, its SD increases by five times. The increase of eccentricity has opposite effects on the vibration displacements of high- and low-pressure rotors. The variation of the radial clearance of the inter-shaft bearing has a complex influence on the dual-rotor system. As the radial clearance increases, the displacement dispersion of the low-pressure rotor along θx direction is almost unchanged. However, that along x1 direction is increased. [ABSTRACT FROM AUTHOR]