Research On Fatigue Characteristics Of AC25kV Overhead Rigid Catenary Cantilever Support Device

The rigid catenary has the advantages of simple structure,large current capacity and low clearance requirements,and has been widely used in urban rail transit.As the urbanization of China continues to accelerate,the distance between station lines of urban rail trains is gradually increasing,and the increase of the running speed of electric locomotives becomes inevitable.Compared with the traditional DC1500 V rigid catenary,the AC25 kV rigid catenary has a higher voltage level and a longer power supply arm,which is suitable for higher speed urban rail trains.However,as the speed increases,the problem arises whether the rigid contact mesh components can be in good service at higher speed levels.The cantilever arm support device is an important part of the AC25 kV rigid catenary system.Therefore,it is necessary to carry out research on the fatigue characteristics of the AC25 kV rigid catenary cantilever support device.In this paper,AC25 kV rigid catenary cantilever support device is taken as the research object,and its fatigue characteristics are studied by means of fatigue mechanism analysis,pantograph-catenary dynamic simulation,damage equivalence and fatigue test.Firstly,based on the fatigue theory,the fatigue mechanism of the rigid catenary arm support device was analyzed from the aspects of its own fatigue limit and the dynamic stress during the dynamic interaction of the catenary,so as to provide a theoretical basis for the study of the fatigue characteristics of the rigid catenary cantilever support device.Secondly,a 160km/h velocity class AC25 kV rigid catenary pantograph simulation model was established by finite element method.The time history of anchor point stress and lifting displacement at different locations was obtained through dynamic simulation of the pantograph-rigid catenary.The time history of anchor point stress and lifting displacement was analyzed and studied.Based on the damage equivalent theory,the damage equivalent scheme of the zero-mean stress maximum amplitude cycle in the original load spectrum is taken as the equivalent load spectrum of the original load spectrum.The validity of the load spectrum damage equivalent scheme is verified by the actual case.Based on the given load spectrum equivalent scheme,the fatigue program spectrum of the AC25 kV rigid catenary cantilever support device is obtained.Finally,combined with the fatigue program spectrum and fatigue mechanism,the fatigue test scheme is given,and the fatigue test bench is built.Based on this,the fatigue test of the AC25 kV rigid catenary cantilever support device under different loading conditions is carried out.Combined with the fatigue test results and fatigue theory,the fatigue characteristics of the AC25 kV rigid catenary cantilever support device were analyzed.Through the analysis of the fatigue mechanism,the self-fatigue resistance of the AC25 kV rigid catenary cantilever support device is affected by external environment,surface roughness and its own structure.The dynamic stress of the arch piont is the main reason for the fatigue failure.The greater the dynamic stress of the anchor point,the more likely the fatigue contact failure of the AC25 kV rigid catenary cantilever support device is,and the fatigue life is smaller.The fatigue test results show that the fatigue failure of the AC25 kV rigid catenary cantilever support device occurs mostly in the positioning line clamp elastic unit,and a very small number of failures occur in the wrist pin vertical pin hole gasket;as the dynamic peak force of the anchor point increases,the durability of the AC25 kV rigid catenary cantilever support device is worse,and its law basically conforms to the load/life rule of the structural material;when the peak force of the anchor point is less than 140 N,the AC25 kV rigid catenary cantilever support device enters the infinite life fatigue stage.