Simulation Of Fretting Wear Resistance Of Aviation Involute Spline Coatings

When the aviation involute splines are working under the special load condition and harsh working environment,slight movement between the tooth surfaces is easy to happen,resulting in fretting wear,which greatly shortens the service life of the spline pair and reduces the reliability of the aviation transmission system.At present,the fretting wear analysis of the aviation involute spline is not thorough enough.Therefore,it is necessary to study the fretting wear phenomenon and the effective wear reduction method of the aviation involute spline,to analyze the related factors affecting the wear,and to prolong the service life of the aviation involute spline,which has an important engineering significance to improve the reliability of the aviation transmission system.In this paper,a finite element model of the fretting for the aviation involute spline was firstly established.By applying cyclic variable loads,the finite element analysis of fretting condition of the involute spline was carried out by using transient simulation method,and the stress distribution and sliding distance of the involute spline were obtained.The wear was estimated based on the Archard equation,and the accuracy of the finite element model was verified by comparing with the practical working wear.After that the stress distribution of the involute spline tooth surface and the stress difference between the teeth were explored.At the same time,based on the power spectrum of the reducer,the stress of the aviation involute spline under practical working conditions was solved,and the friction contact characteristics of the involute spline and the effect of fretting amplitude,dynamic load coefficient and misalignment on fretting wear were revealed.The research on the fretting wear of the involute spline shows that the stress concentration of the spline is located near the dedendum in the meshing area,the stress and sliding distance of each tooth change with the rotation of the spline pair,there is a big difference in the distribution of sliding distance,and the stress is much more affected by the rotation speed than the torque;from axial load input end to axial load output end,the contact stress and fretting wear depth gradually increase,the fretting wear at the dedendum is the most serious,and the simulation results have the same distribution and growth trend as the engineering test values;in the fretting interval,the contact stress and fretting wear depth of spline increase as the increase of fretting amplitude and dynamic load coefficient,under the same load,the larger the dynamic load coefficient is,the more unbalanced the stress distribution between the teeth is;both axial misalignment and angular misalignment will lead to the change of the spline pair clearance,the fretting wear and stress unevenness become more serious with the increase of the misalignment,and the self-centering characteristics of the spline pairs can produce a certain amount of centering compensation and weaken the impact of the misalignment.Then,based on the contact mechanics analysis,the stress conditions before and after the formation of the transfer layer on the coating surface were accurately described,a finite element model of the coating-spline pair was established,the stress nephogram and the stress of contact surface and bonding interface before and after the transfer layer forming were researched,and the main factors influencing the anti-fretting wear performance of the coating were explored.Then the fretting wear resistance of the composite coating was studied,and the coating parameters with the best mechanical properties were obtained.Finally,a fretting wear geometric updating was performed on the finite element model of the coating-spline pair,and the fretting wear resistance effect of coating was tested.The research on the fretting wear resistance of the coating shows that with the occurrence of fretting,the stress of the coating and the substrate changes significantly,the bearing area gradually expands,the stress becomes more uniform,and the influence of tangential force reduces;with the expansion of the contact area,the stress distribution on coating surface and bonding interface tends to be the same,and the amplitude gradually decreases;due to the material difference between the coating and the substrate,the shear stress at the bonding interface is larger,which is one of the inducements of coating spalling failure;when the Young’s modulus is 300 GPa,Poisson’s ratio is 0.22,the coating thickness is 0.05 mm,and the friction factor is 0.1,the single-layer coating can effectively reduce the stress on the contact surface and better transmit the load,and the bonding between coating and substrate is improved at the same time,meanwhile the double-layer composite coating has better mechanical properties.Compared with that of uncoated spline,the maximum fretting wear depth of single-coated spline and double-coated spline are reduced by 17.5% and 29.4% respectively,which indicates that reasonable coating surface technology can effectively improve the friction behavior of the aviation spline and mitigate fretting damage.