Vibration model of rolling element bearings in a rotor-bearing system for fault diagnosis

Rolling Bearing element is used in Rotating Machinery; complexity of lading mechanism in bearing which influence the vibrational local defects (faults). These faults are the reason of breakdown in rotating machines. Rolling bearing fault model is based on the dynamic load analysis of a rotor-bearing system. The rotor impact factor is consideration in the rolling bearing fault signal model. The defect load on the surface of the bearing is divided into two parts, the alternate load and the determinate load. In this paper we are going to study outer race and inner race fault simulations. The simulation process includes following parameter; the gravity of the rotor-bearing system, the imbalance of the rotor, and the location of the defect on the surface. The simulation results show that different amplitude contributions of the alternate load and determinate load will cause different envelope spectrum expressions. In the envelope spectrum the rotating frequency sidebands and fault characteristic frequency will occur. This appearance of sidebands will increase the difficulty of fault recognition. The test rig design of the rotor bearing system simulated several operating conditions: rotor bearing, rotor bearing with loader, rotor bearing with loader and rotor disk and bearing fault simulation without rotor influence. Hence we conclude that the rolling element bearing fault signal model is important to the fault diagnosis of rotor-bearing systems.