Uncertainty analysis of simplified spline coupling model and its impact on rotor dynamic characteristics

XI Jiali; GUO Qintao; LIU Jiwen; JIA Zhigang

doi:10.16579/j.issn.1001.9669.2026.06.003

Abstract：[Objective]In the rotor dynamic calculation of aero-engine,spline coupling is usually omitted,which leads to the problem that the influence of the change of its stiffness characteristics on the rotor dynamic characteristics cannot be reflected.Aiming at this problem,a simplified model was established considering the stiffness characteristics of the spline coupling,and the related rotor dynamic analysis and calculation were carried out.[Methods]Firstly,according to the simplified method of the equivalent stiffness of the spline coupling,the single-sided spline coupling of an aero-engine test bench was simplified,and a simplified model of the spline coupling was established.Secondly,the test pieces were used to carry out the relevant rotor inherent characteristic test,and the parameters of the simplified model were identified according to the test results,and the uncertainty of the parameters was analyzed.Finally,the influence of the critical speed and strain energy of the rotor was studied for the elastic modulus of the equivalent shaft section in the simplified model.[Results]The test results show that the maximum calculation frequency error between the simplified rotor model and the test model is less than 3％,which proves that the simplified modeling method of the spline coupling has high reliability and accuracy,and the accuracy of the model is better improved by parameter correction.Through the analysis of parameter uncertainty,it is proved that the simulation prediction calculation is in good agreement with the test.In the rotor dynamic calculation of the simplified model,it is found that with the increase of the equivalent elastic modulus of spline coupling,the critical speed of each order and the strain energy of the rotor increase in different ranges.This study provides a method and reference for the efficient design of rotor with spline coupling and the dynamic analysis of the whole machine in the subsequent engineering practice.