TY - JOUR N2 - Shaft-stator rub and cracks on rotors, which have devastating effects on the industrial equipment, cause nonlinear and in some cases chaotic lateral vibrations. On the other hand, vibrations caused by machinery faults can be torsional in cases such as rub. Therefore, a combined analysis of lateral and torsional vibrations and extraction of chaotic features from these vibrations is an effective approach for rotor vibration monitoring. In this study, lateral and torsional vibrations of rotors have been examined for detecting cracks and rub. For this purpose, by preparing a laboratory model, the lateral vibrations of a system with crack and rub have been acquired. After that, a practical method for measuring the torsional vibrations of the system is introduced. By designing and installing this measurement system, practical test data were acquired on the laboratory setup. Then, the method of phase space reconstruction was used to examine the effect of faults on the chaotic behaviour of the system. In order to diagnose the faults based on the chaotic behaviour of the system, largest Lyapunov exponent (LLE), approximate entropy (ApEn) and correlation dimension were calculated for a healthy system and also for a system with rub and a crack. Finally, by applying these parameters, the chaotic feature space is introduced in order to diagnose the intentionally created faults. The results show that in this space, the distinction between the various defects in the system can be clearly identified, which enables to use this method in fault diagnosis of rotating machinery. L1 - http://www.czasopisma.pan.pl/Content/115050/PDF/05_MMS_1_2020.pdf L2 - http://www.czasopisma.pan.pl/Content/115050 PY - 2020 IS - No 1 EP - 80 DO - 10.24425/mms.2020.131719 KW - rotor vibrations KW - crack KW - rub KW - fault detection KW - chaos features KW - largest Lyapunov exponent KW - approximate entropy KW - correlation dimension A1 - Hajnayeb, Ali A1 - Shirazi, Kourosh Heidari A1 - Aghaamiri, Reza PB - Polish Academy of Sciences Committee on Metrology and Scientific Instrumentation VL - vol. 27 DA - 2020.03.18 T1 - Vibration measurement for crack and rub detection in rotors SP - 65 UR - http://www.czasopisma.pan.pl/dlibra/publication/edition/115050 T2 - Metrology and Measurement Systems ER -