Rotor-bearing system pedestal looseness state assessment method

The present invention discloses a rotor-bearing system pedestal looseness state assessment method. The method comprises the following steps: 1) establishing an elastic force expression in a vertical direction generated by a gap of the rotor-bearing system caused by pedestal looseness, and establishing a non-linear dynamics model of the rotor-bearing system when there are pedestal looseness faults; 2) performing Taylor expansion of the nonlinear terms to obtain a linear approximation dynamical model, and comparing the non-linear model and the linear approximation model dynamic behavior; 3) calculating the nonlinear degree of the dynamic behavior of the rotor-bearing system with different-size looseness gaps; and 4) performing nonlinear fitting of the discretization result of the nonlinearity degree value, and establishing the corresponding relation between the pedestal looseness degree and the nonlinearity degree assessment value to realize the assessment of the rotor-bearing system pedestal looseness state. The rotor-bearing system pedestal looseness state assessment method can assess the rotor-bearing system pedestal looseness state to effectively avoid the occurrence of big gap looseness condition of the rotor-bearing system and avoid the occurrence of the disastrous accidents.