Comparative Analysis of Contact Mechanical Characteristics of Involute Spline Pairs under Different Modification Methods

• A unified finite element framework was established to comparatively analyze contact evolution of involute splines under angular and axial misalignment. • The nonlinear stress amplification and edge-localization mechanisms induced by misalignment were systematically characterized. • An optimal 0.02 mm crowning modification reduced peak contact stress by up to 63.8% and stabilized load redistribution across misalignment levels. Involute splines are critical in aerospace transmission systems but are susceptible to failure due to uneven wear. Profile modifications offer an effective strategy to mitigate tooth surface stress concentrations. This study systematically compares Crowning Modification, Tooth-End Thinning, Flank Slope Modification, and Wear-Based Parabolic Modification using finite element simulations under rated torque. Results reveal that all methods reduce tooth-end stress concentration, yet their mechanisms and effectiveness differ markedly. Notably, Crowning Modification excels in shifting load toward the tooth center and achieving uniform stress distribution, reducing peak contact stress by over 60%. These findings provide a robust theoretical and technical basis for optimizing aerospace spline designs.