Analysis and identification of rub-impact fault between rotor and stator

Based on the background of rub-impact faults of aeroengines and industrial turbines, two kinds of test rigs with free supports are established according to a dynamic model to study the rub-impact faults between the rotor and the stator. The orbits of the vibration of rotor displacement corresponding to four different impact conditions are respectively examined, which are the normal condition, the early sharp impact condition, the semi-sharp impact condition and the terminal blunt impact condition. The route to chaos, appearing with the early sharp impact, is observed. The analysis of the experimental data on the four impact conditions in the frequency domain shows that the appearance of the subharmonic vibrations of the order 1/3 and 1/4 is the effective evidence for initial light rub-impact, and the harmonic vibrations of the order of 1/1 and 1/2 are for the very serious rub-impact faults.