Study On Fatigue Characteristics Of Ac Pantograph Frame

As an important medium for trunk railway vehicles to collect current from catenary,AC pantograph plays a very important role in pantograph-catenary system.With the continuous prominence of the advantages of AC power supply system relative to DC power supply system,AC pantograph is gradually introduced into urban rail transit.With the increase of railway load and operation mileage,flaws and cracks occur in AC pantograph frame before reaching the design life,which not only increases the maintenance cost of pantograph,but also seriously affects the reliability of normal current taking and matching contact network of train.Therefore,it is of great significance to study the fatigue characteristics of AC pantograph frames.This paper takes an AC pantograph as an example.Firstly,various stresses on the pantograph frame are deduced according to material mechanics.It shows that the pantograph frame is subjected to complex alternating stresses under various loads,which is the main reason for fatigue cracks of the pantograph.Based on ANSYS finite element model,the effects of balance rod,static contact force,working height and pull-out value on the maximum stress of pantograph parts are analyzed.It is found that static contact force has relatively greater influence on the maximum stress of pantograph parts.Meanwhile,the natural frequency and vibration mode of pantograph are obtained by modal analysis.On the other hand,the static stress of pantograph frame is tested at different locations,which verifies the accuracy of the simulation results.The relationship between the stress of test point and contact force and working height is also measured.It is found that the stress of upper arm test point decreases mostly with the increase of working height,the stress concentration increases,the stress of lower arm bar increases,and the working height has little influence on the pantograph frame as a whole.In dynamic testing,it is found that frequency has a certain effect on the stress of each test point.Analyzing each test point at a specific frequency of 13.5Hz,it is found that their mean values are basically consistent with the static stress data.Therefore,the static simulation model can be used to simulate the fatigue life.Finally,based on the static simulation results,the fatigue life simulation model is established in nCode,and the fatigue life of pantograph frame is simulated and calculated under lifting pantograph and different contact force operation conditions.The results show that the fatigue life of pantograph frame meets the standard design requirements.By comparing the fatigue life of pantograph frame under different contact force conditions,the average contact of pantograph frame is considered.The fatigue life is longer when the contact force is 80 N and the standard deviation of contact force is smaller.