Jean Yves Cholley’s scientific contributions

The use of Active Magnetic Bearings (AMBs) in the High Speed Machining (HSM) field is increasing. In fact, they have important advantages such us: high speed which can reach 150000 rpm, high stiffness and absence of lubrication. Indeed, these bearings operate through magnetic interaction generated between the stator and the rotor. The spindle, principal component in the HSM, supported by AMBs, is considered as a source of vibration in machine tool spindles when it is affected by some defects during their functioning. These defects can affect either the rotor of the spindle like the unbalance defect, or the AMBs such us misalignment of bearings, failure of actuators, sensors, amplifier and also the eccentricity defect. This paper studies the influence of spindle or AMBs defects on the dynamic behavior of a spindle supported by two AMBs. The system modeling is based on the finite element method. Four degrees of freedom is used and the coupling between elastic and rigid displacements is taken into account.