Dynamic characteristics of rotor system and rub-impact fault feature research based on casing acceleration

Abstract

Aimed at the vibration of whole aero-engine, a coupled dynamic model of rotor-ball bearing-stator of aero-engine is built. By means of the lumped mass method, taking into account the nonlinear rub-impact, bearing failure force and deformation of the casing, the dynamic equation of the system containing typical rub-impact is derived. The response of the system under different conditions is obtained by using the fourth order Runge-Kutta numerical integration algorithm. By adopting the finite element analysis software ANSYS, the finite element model of the rotor shaft is established and the first six-order natural frequencies of the rotor system are acquired. Taking advantage of the parameters of the signal in time domain and frequency domain, frequency characteristics are extracted as the fault features. The single-point rubbing experiment is carried out in the test rig, and the working speed is higher than the first critical speed, so the rotor shaft is flexible rotor. By the methods of spectrum and cepstrum analysis, the rub-impact characteristics of the casing vibration acceleration time series data are analyzed. The results show that the casing vibration acceleration has obvious impact characteristics; the impact frequency is equal to the product of rotating frequency and number of the blades; the impact frequency component and its multiple-frequencies are demonstrated in the frequency spectrum; the strength of impact is modulated by the rotating frequency, so that there are families of side bands on impact frequency and both sides of frequency doubling, and the interval of sideband equals the rotating frequency. The frequency components of the rotating frequency and its frequency doubling are clearly shown in the cepstrum. By comparing the simulation and experiment, the rubbing characteristics found out in this paper has enough accuracy.how to do a better design, but also the teamwork spirit, the attitude of respect and reverence for technology, which is more important in research.Nanfei Wang is a Ph.D. Candidate in Department of Thermal Engineering from Tsinghua University, Beijing, China. Major in mechanical vibration and dynamic analysis of rotating machine; finite element analysis; condition monitoring and fault diagnosis; dynamic modeling and simulation Dongxiang Jiang is a Professor of

Rub-impact fault identification of a bladed rotor based on chaotic features

“…Chen [5] also investigated the casing vibration induced by blade rubbing for the identification of this fault. Wang [6] revealed the rubbing characteristics of the casing vibration acceleration for fault diagnosis. Leong [7] examined blade pass frequencies and its side bands for blade rubs.…”

Identifying rotor-stator rubbing positions based on intrinsic time scale decomposition-hjorth-cepstrum

“…The literature (Liska et al, 2011) proposed an online accumulation full spectrum method based on full spectrum calculation, which calculates the characteristic value of rubbing with the specialness normalization of tracking frequency in accumulation full spectrum and thereby makes online detection on rubbing faults possible. In view of the integral vibration of aero-engine, the literature (Wang et al, 2016) has established a rotator-ball-bearing-stator coupling dynamical model and taken advantage of spectrum analysis and reverse spectrum analysis to explore the rubbing characteristics of time sequence data of casing vibration acceleration.…”

“…The literature (Liska et al, 2011) proposed an online accumulation full spectrum method based on full spectrum calculation, which calculates the characteristic value of rubbing with the specialness normalization of tracking frequency in accumulation full spectrum and thereby makes online detection on rubbing faults possible. In view of the integral vibration of aero-engine, the literature (Wang et al, 2016) has established a rotator-ball-bearing-stator coupling dynamical model and taken advantage of spectrum analysis and reverse spectrum analysis to explore the rubbing characteristics of time sequence data of casing vibration acceleration. The literature (Zheng et al, 2017) proposes a self-adaptive parameter-free empirical wavelet transform (EWT) method on the basis of EWT; literature (Hou et al, 2019) takes advantage of multipath effects to study the extraction and identification of rubbing fault characteristics by rotor-casing vibration signal model of aero-engine.…”

Study on Vibration Characteristics of Polishing Rod for Polishing Aeroengine Blade with Abrasive Cloth Wheel

“…According to the change of grinding force with workpiece speed, the change of workpiece high-frequency speed can be used to reduce chatter. Aiming at the rub-impact phenomenon of main components in the normal operation of an aeroengine, Wang et al [33][34][35][36] studied the dynamic response of the main components in the time and frequency domains by theoretical analysis, simulation, and experimental methods.…”