Research and optimization analysis of contact stress characteristics in spline pairs of aviation transmission systems

Aerodynamic spline couplings commonly suffer from uneven load distribution caused by misalignment, leading to severe edge stress concentration that threatens the reliability of transmission systems. This paper proposes an integrated simulation-surrogate-optimization design method, which collaboratively optimizes key geometric parameters such as the chamfer at the ends of internal and external splines, tooth thickness adjustments, and contact length. Analysis confirms that misalignment is the primary driver of stress exacerbation. The optimized design effectively suppresses stress peaks, significantly reduces maximum contact stress, and maintains superior performance under various loading and misalignment conditions, demonstrating high robustness. This study provides a systematic optimization strategy for mitigating spline load misalignment, offering significant engineering guidance for enhancing the performance and lifespan of aerospace transmission components.