Uncertainty analysis and optimization of contact stress for the centering surface in aviation splines considering surface topography

The centering surfaces of aviation splines (CSAS) are critical for maintaining alignment and stability in aero-engine rotor systems. Misalignment of CSAS triggers excessive wear, unstable torque transmission, and heightened safety risks. In this study, the deterministic contact mechanics model is established based on the fractal theory to predict the mean contact stress (MCS) of CSAS. Then, the interval model of MCS is derived based on the Chebyshev polynomial expansion and the deterministic contact model, and the constructed model is verified by experimental results. Additionally, the multi-objective uncertainty optimization model was proposed to determine the optimal design strategy of CSAS, with the optimization goal of minimizing both the upper bound of MCS and the uncertainty coefficient. Finally, the uncertainty analysis of MCS is carried out, and optimization results are also discussed in detail. Results indicate that the upper bound of MCS is sensitive to topography parameters and the radial offset, and the optimized solution ensures the upper bound of MCS remains within the safety margin while significantly enhancing system robustness. This study provides effective theoretical guidance for improving the design of centering surfaces and enhancing the load-bearing capacity of aviation splines.