Rotor Design Optimisation through Low Cycle Fatigue Testing

The current work aims at modifying the rotor geometry to improve the alternator performance. For that purpose, the fatigue behaviour of the material needs to be defined. Experimental tests were conducted on the Fe-3Si steel constituting the rotor. It is shown that this material hardens under cyclic loadings and TEM observations revealed unusual damage mechanisms. From the experimental LCF tests, the material parameters needed for FEA and the fatigue resistance law have been defined. The FEA results were validated on smooth and notch samples. Finally, the rotor design is modified which enables a light-weighting of the magnet or an increase of the torque value depending on the considered rotor and purpose.