Impact of Manufacturing Variability on Motor Material Properties and Its NVH Behavior

This study investigates the influence of glue coverage and stacking factors on the effective macroscopic mechanical properties of dot-glue adhesively laminated stator cores and the impact of these manufacturing-related attributes on the motor and the electric drive system's structural performance, particularly in terms of noise, vibration, and harshness (NVH). A homogenization framework based on the unit-cell method was developed to model glue-laminated stacks as orthotropic materials suitable for finite-element analysis (FEA) of partially bonded cores. Also, a closed-form analytical solution is proposed to predict the macro-mechanical properties of a core composed of isotropic constituents with the consideration of glue coverage. The approach enables systematic quantification of variations in glue coverage and stacking factor to predict the effective in-plane and out-of-plane elastic and shear moduli of the stator core. For modeling simplicity, glue is assumed to be uniformly distributed across the lamination plane at a specified coverage rate, and the adhesive layer thickness is calculated statistically as the average of the estimated values from the stacking factor. Numerical predictions from the unit-cell approach are compared with experimentally correlated material properties from production cores and with theoretical results, demonstrating excellent agreement among simulated, analytical, and measured values. Results reveal that these manufacturing parameters significantly affect NVH performance of the motor and e-drive system, underscoring the need to incorporate them into CAE predictive models to enhance reliability and accuracy. The proposed method provides a validated analytical framework and a practical design tool for integrating manufacturing variability into the mechanical evaluation of electric motors and drive systems.