The crack generation has great influence on the vibration characteristics of inclined screen rotating shaft, so it is very important to study it. The rotational mechanical characteristics of inclined screen hollow cracks are studied. Considering the inclined screen dynamic morphology, a bent-torsion coupling dynamic model of hollow crack shaft influenced by nonlinear vorticity is established, and the influences of crack depth and inclined screen amplitude on vibration characteristics of the shaft system are analyzed. The results show that the presence of cracks will not only lead to high frequency doubling in response, but also the larger the crack depth, the larger the amplitude of each frequency doubling, and the increase is obvious: inclined screen amplitude has the biggest influence on the main frequency component of the system: With the increase of rotating speed, the nonlinear vibration characteristics of the rotating shaft system are more complex.
Inclined screen plays an indispensable role in the gold treatment industry, among which the three-axis banana oval inclined screen has the advantages of high efficiency and reliable performance. inclined screen rotating shaft is the key component that determines the high efficiency and high performance operation of inclined screen system. Due to the peculiarity of inclined screen movement and working environment, the rotating shaft is subjected to alternating load for a long time. The initial small crack will expand and form a large crack until the rotating shaft becomes unstable or fractured, resulting in major accidents. Therefore, crack failure is most common in inclined screen rotating shaft. Therefore, it is necessary to establish a reasonable dynamic model for the dynamic analysis of inclined screen rotating shaft.
In order to avoid major accidents caused by cracks, a large number of scholars have studied the dynamic characteristics of cracked rotating shaft. Through the experimental study of the dynamic characteristics of nonlinear cracked rotor, it is found that when the rotor passes the subcritical speed, the system will appear high order harmonics. The effectiveness of electromagnetic bearings for on-line monitoring of respiratory cracks in the rotor system is proved both theoretically and experimentally. Inlined screen the dynamic characteristics of the double-disc rotor bearing system supported by double oil film, and finds that the inclined screen system is mainly inclined in period-doubling or pseudo-periodic bifurcated motion when unstable, and a small eccentricity can increase the rotational speed of instability. Considering the tangential stiffness, the bifurcation and chaos of the rotor system were studied. With the increase of the normal stiffness of the crack, the bifurcation of the cracked rotor through the subcritical speed, the pseudo-period, the period 3 solution and other motions occurred. The fault diagnosis of cracked rotor of induction motor is carried out by an improved method.
The multi-frequency harmonic excitation is used for crack fault diagnosis. It is found that periodic excitation can not only detect faults, but also quantitatively analyze the detection results. Jing Beibei conducted fault diagnosis for cracks based on empirical model and found that demd has better detection effect than traditional emd method. The coupling modes of a flexible rotor supported by a superconducting magnetic bearing are studied. It is found that there is a nonlinear coupling between the first and second modes. Li Ning studied the breathing characteristics of the crack passing through the critical speed of the rotating shaft and found that the unbalance azimuth Angle has a great influence on the critical speed. Considering mass unbalance and gyro effect, it is found that mass unbalance is the main factor causing bent-torsional coupling vibration. He Chengbing used the small parameter method to obtain the analytical solution of the bent-torsional coupled vibration equation, and found that when the rotational speed is equal to the sum or difference of the natural frequencies of the bending vibration and the torsional vibration, the bent-torsional resonance phenomenon may occur in the system. Dou Wei analyzed the rotor system of high speed gear and studied the influence of eccentricity and gear meshing stiffness on the vibration characteristics of the system. Liu Changli established the finite element model of rotor with oblique crack and analyzed the effect of different crack depth on vibration characteristics of rotor subsystem. However, no bend-torsional coupling dynamic equation has been established and vibration characteristics have been analyzed for inclined screen hollow cracked rotating shaft system. Therefore, for inclined screen rotating shaft, the bent-torsional coupling dynamic equation of hollow cracked rotating shaft system is established in the case of non-gravity dominance, and the influence of each important parameter on the amplitude and frequency characteristics of the system and nonlinear characteristics such as bifurcation and chaos is analyzed. Axis locus, amplitude-frequency characteristic diagram, phase diagram, bifurcation diagram, Poincare section diagram and bifurcation diagram are used to analyze the influences of crack depth, inclined screen dynamic amplitude and shaft speed on the bifurcation and chaos characteristics of the crack shaft.
