Numerical and Experimental Evaluation of Winding-Corner Integrity in an Fe-5.0 wt.%Si Soft Magnetic Composite Stator Core for Direct-Winding Applications.

Direct winding places magnet wires in direct contact with soft magnetic composite (SMC) stator cores, making the winding-corner response important for component design. This study evaluated an Fe-5.0 wt.%Si SMC stator core through finite element analysis and corner-loading tests. Based on a wire tension of 1.44 N/turn and a 90° change in winding direction, the resultant load was 2.04 N per turn and 38.7 N for 19 turns. An engineering verification load of 177 N was defined from the mean nominal 0.2% proof load of the AI-EIW wire. The equivalent distributed model at 38.7 N and the representative one-turn circular-contact model at 2.04 N predicted elastic responses without effective strain. At 177 N, the maximum effective stress and strain were 876.9 MPa and 0.0132, and the maximum resultant displacement after unloading was 0.85 μm. Component-level tests showed continuous force increases to the prescribed loads. Optical microscopy at 20× magnification identified no indentation, cracking, edge chipping, particle detachment, or corner-profile change after unloading, although the FEA-predicted sub-micrometer localized deformation was not directly quantified by the optical evaluation. These results characterize the local mechanical response under the defined reference winding and engineering verification conditions.