Research On Calculation Method Optimization Of Equivalent Mass And Structure Strength Evaluation Of High-speed Pantograph

The steady current-collection quality of the pantograph is the key point to the safe operation for high-speed train,and the steady current-collection of the high-speed pantograph depends on the structure and strength of the pantograph.At present,the equivalent mass models are almost used as the mechanical model to study on the dynamic characteristics of the pantograph at home and abroad.The equivalent mass is the important parameter for the pantograph performance.When the high-speed pantograph is in operation,it bears complex alternating loads such as air resistance,pantograph catenary contact force and vehicle vibration,which may cause fatigue cracks or fractures during the operation period.Therefore,the qualified structure strength is the basis for current-collection of the pantograph.Based on equivalent mass model of the pantograph and evaluation method for structure strength of railway vehicle,in this thesis calculation method of the equivalent mass and the structure strength of the pantograph have been investigated,and this dissertation did following researches:Based on the three-mass equivalent model,the research status of pantograph equivalent mass and its calculation methods were analyzed.The traditional calculation method was optimized and the optimization scheme in this thesis was proposed.Considering all parts of the pantograph,a plane mathematical model of the pantograph is established.Based on the finite element method and free vibration attenuation method,the theoretical basis and calculation process of calculation for the equivalent mass of the upper frame were studied.According to the experimental data,the calculation results of the optimization method were compared with the calculation results of the traditional method and the correctness of the optimization method in this thesis was verified.Based on the optimized calculation method for the equivalent mass of this dissertation,the influencing factors for equivalent mass of the frame,such as operating height,structure parameters of parts and types of the collector head,have been investigated.The relation between equivalent damping of the frame and working height and installation position parameters of damper was analyzed.Influencing factors for equivalent mass of the upper and lower frame have been investigated by finite element method and free vibration attenuation method.The influence of the types of upper arm,material,thickness,cross-section shapes of longitudinal tube,variable cross-section longitudinal tube and rubber joint on the equivalent mass parameters of pantograph was analyzed.The loads of high-speed pantograph have been analyzed.According to the operation test data on railways,wind tunnel test data and related standards of pantograph,the load cases of static and fatigue strength of the high-speed pantograph were calculated.On the basis of ORE method,the maximum and minimum principal stresses of nodes on pantograph weld were obtained,and the fatigue strength of pantograph was evaluated by the modified Goodman curve of the material.According to DVS method,the local coordinate systems of spatial straight line and curved welds were solved.The node stress solution of finite element was used to calculate the material utilization rate and nominal stress related to the weld direction,and evaluate the fatigue strength of pantograph.Based on the fatigue evaluation results of ORE method and DVS method,the differences of these two fatigue evaluation methods were analyzed and compared.