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The automotive industry is shifting towards the development of hybrid electric and electric vehicles. These vehicles primarily use electric motors for propulsion and can be significantly quieter to pedestrians than traditional ICE (internal combustion engine) vehicles. The NFB (National Federation of the Blind) and others highlighted a concern with these quiet vehicles related to pedestrian safety and the inability to use historical sound signatures to detect a moving vehicle. To address this concern, NHTSA created FMVSS 141, which identifies minimum external sound requirements for hybrid and electric vehicles during stationary conditions and in motion up to 30kph. [1] OEMs are now required to implement Acoustic Vehicle Alerting Systems (AVAS) that use external speakers to generate additional noise to meet the regulation.

Strict environmental regulations are driving the automotive industry toward electric vehicles as they offer zero emissions. A key component in electric vehicles is the electric motor, where the stator and rotor are manufactured from stacks of thin electrical steel sheets. The electrical steel sheets can be cut in different ways, and the cutting methods may significantly affect the fatigue strength of the component. It is important to understand the effect of the cutting processes on the fatigue properties of electrical steel to ensure there is no premature failure of the electric motor resulting from an improper cutting process. This investigation compared the effect of three different edge preparation methods (stamping, CNC machining, and waterjet cutting) on the fatigue performance of 0.27mm thick electrical steel sheets. To investigate the effect of the edge finish on fatigue behavior, surface roughness was measured for these different samples.

Electrical steels are silicon alloyed steels that possess great magnetic properties, making them the ideal material choice for the stator and rotor cores of electric motors. They are typically comprised of laminated stacks of thin electrical steel sheets. An electric motor can reach high temperatures under a heavy load, and it is important to understand the combined effect of temperature and load on the electrical steel’s performance to ensure the long life and safety of electric vehicles. This study investigated the fatigue strength and failure behavior of a 0.27mm thick electrical steel sheet, where the samples were prepared by a stamping process. Stress-control fatigue tests were performed at both room temperature and 150°C. The S-N curve indicated a decrease in the fatigue strength of the samples at the elevated temperature compared to the room temperature by 15-25 MPa in the LCF and HCF regimes, respectively.