Reliability Analysis Of Rubbing Rotor System Based On Performance Degradation

Rotating machinery plays a pivotal role in aviation,transportation,electric power and other fields.The rotor system is a key component of rotating machinery,and its performance status determines whether the machine can run for a long time.According to statistics,there are many common faults in the rotor system,including rotor rubbing fault,misalignment faults,thermal bending faults,blade vibration faults,loosening faults,fatigue cracking faults,rolling bearing faults,etc.Among them,Rotor rubbing fault has the characteristics of high incidence and serious consequences once it occurs.When the rotor is working,the rotor system will go through a process from normal to degradation to failure.During this period,it will experience a series of different performance degradation states.The accumulation of this performance degradation will lead to the gradual degradation of product functions,and the performance indicators such as internal strength and stress of the system will degrade,which will ultimately make the product invalid.The performance degradation process contains a large amount of credible information that is closely related to the product life.In the context of this problem,the reliability analysis of the rotor rubbing based on the performance degradation comes into being.In this paper,starting from the failure physical model of the rotor rubbing,the limit state equation of the rotor system was established,and the main parameters that affect the performance degradation of the rotor system were determined by observing the nonlinear dynamic equations.Refer to the literature to determine the degradation model,and the non-linear dynamic differential equation of rotor rubbing with performance degradation was established.Second-order moment technology,random perturbation theory,Kronecker algebra,matrix differentiation,etc,were used to systematically study the random response analysis of rotor rub-impact.The statistical characteristic curves of the mean value and variance of the radial displacement of the turntable under the influence of rub-impact faults could be observed.In this paper,the average first-order second-order moment method was used to calculate the reliability and reliability sensitivity,and the influence of design parameters such as stiffness,mass,damping,and eccentricity on the system reliability could be observed.Observing the transient reliability,it could be found that the performance of the rotor system degraded under the influence of stiffness degradation and slow quality changes after 2400s,and the transient reliability slowly decreased with time.By observing the reliability sensitivity,it was found that different random variables had different effects on the reliability.The turntable damping c2,the shaft stiffness k,and the stator stiffness kr had a positive effect on the rotor system,and the eccentricity e and the turntable mass m2 had a negative effect on the rotor system.Different random parameters had different effects on the reliability of the system.From high to low,they were:eccentricity e,turntable damping c2,shaft stiffness k,turntable mass m2,stator stiffness kr.This article provided a certain theoretical basis for the reliability optimization of the rotor system.