This study presents an effective predictive methodology for determining the mechanical properties of glue-laminated motor cores, with explicit consideration of glue disposition, including bonding pattern, configuration, location, and coverage. In laminated stator cores, glue bonding and stacking processes jointly govern the mechanical integrity of the lamination stack. Practical production bonding schemes are typically nonuniform and localized, leading to spatial variations in stiffness and to locally anisotropic, orthotropic material behavior. These effects influence both the in-plane and through-thickness stiffness of the stator core. They can significantly affect the accuracy of structural simulations, such as NVH responses of high-speed traction motors and e-drive systems.
Given the constituent material properties of the electrical steel laminations and the glue, this work distinguishes the governing mechanisms underlying the equivalent core properties. The in-plane stiffness is primarily controlled by the stacking factor, which statistically characterizes the glue contribution in the axial direction. In contrast, out-of-plane properties (e.g., elastic modulus and shear modulus in the stack direction) are determined jointly by the glue’s axial thickness contribution and its in-plane spatial distribution. To capture these coupled effects, an enhanced homogenization framework is developed using a representative volume element (RVE) formulation implemented through finite element analysis (FEA). The laminated structure is represented as an equivalent orthotropic material, enabling directional stiffness variation induced by nonuniform bonding and lamination material. Parametric simulations establish quantitative relationships between macroscopic core properties and glue configuration, bonding pattern, and stacking factors. A closed-form analytical solution is also derived for simplified cases to support verification.
The predicted effective properties show good agreement with experimentally correlated values from production cores, and with analytical solutions under simplified bonding assumptions as well. The proposed methodology enables practical inclusion of glue-disposition effects in early-stage predictive models, thereby improving the fidelity of laminated motor-core NVH assessments and generic structural analysis.