Strength And Dynamic Characteristics Analysis Of Flexible Coupling With Bow Spring

The small aircraft engine generally has the characteristics of high speed and high power.Thus it has very stringent requirements for the coupling which is installed on small aircraft engines.Based on the actual operating conditions,analysis on the elastic coupling including the strength analysis,stiffness analysis and the fatigue life analysis,were conducted.Besides,dynamic characteristics of a elastic coupling-rotor system were also studied.The results are of great theoretical and engineering value for the design of the elastic coupling.The main contents are as following:(1)The contact nonlinear finite element model of coupling was established for a new type of the bow spring elastic coupling with the actual operating condtions.The results show that radial and angular displacement have great influences on maximum stress for the same model with the given load.While the torque and centrifugal load on stress and deformation were relatively small.By comparison between the multi-segment and single-segment bow spring coupling,the multi-segment bow spring coupling has better ability of compensation.Besides,the relationship between torsional stiffness and load is typically nonlinear.The research results have theoretical significance to the bow spring elastic coupling structure.(2)For the single rotor test rig with the bow spring elastic coupling installed,the dynamic characteristics of coupling-rotor system was analyzed.The results show that the critical speed would decrease with the elastic coupling installed.Also,unbalance response of the elastic coupling-rotor system is smaller than that of the rotor system without the coupling.The results show that the coupling could not only compensate the displacement,but also had a certain damping effect.Great correlation is observed between the numerical and experimental results,which proves the correctness and credibility of the model established in this paper.(3)With the given load,a variety of equivalent cycle life prediction methods were applied.With the S-N curve of the material,the fatigue life for the coupling was predicted through the theory of damage.The conservative value for different prediction models are adopted as the fatigue life of the coupling,which provides reference for the application of the bow spring elastic coupling.The research on the new type elastic coupling,which is small,high speed and high power,provides the theoretical guidance and practical reference for the engineering.