Study On The Dynamic Performance And Fatigue Of Rapid Wagon Bogie

With the continuous development of China’s railways towards high speed heavy haul,the development of rapid wagon is imminent,and countries around the world are beginning to develop fast-freight vehicles.The bogie is related to the safety and stability of the train.it is very important to study the dynamic performance of the newly designed rapid wagon bogie.In addition,the rapid wagon bogie framework uses an integrated-welded frame,which is different from the traditional three-piece bogie.As the running speed of the vehicle is increased to 160km/h,the load condition of the train changes,the range of the load frequency of the bogie is widened,and the vibration fatigue problem of the frame weld needs to be studied in detail.In this paper,the dynamic performance and fatigue of the rapid wagon bogie are taken as the research object.Firstly,the dynamic model of the rapid container flat wagon is established.The bogie’s suspension of the wagon is a linear spring to simulate rigid spring,and the second suspension is a non-linear rubber spring.In order to investigate whether the dynamic performance of the line operation meets the design requirements,consider the three states of empty wagon,49 tons and 59 tons,and calculate the safety and stability under the conditions of straight line and R1200\R800\R600\R300 curve line respectively,the nonlinear critical method is used to calculate the critical velocity of the meandering motion of the empty wagon and two different loaded wagons.The dynamic performance calculation is carried out by using the US six-level orbital irregularity spectrum as the excitation.The dynamic performance of multi-rigid-body rapid wagon bogie is evaluated according to the GB/T5599-1985 standard.In order to investigate the vibration fatigue of the welded frame structure of the vehicle under the line running condition,the finite element model of the local details of the welded joint is established.The flexible body file is created by Craig-Bampton modal synthesis method,and the rigid-flexible coupling model is established.The simulation calculates and extracts the modal coordinate response time history of the flexible body frame in the rigid-flexible coupled dynamics model,and then compares it with the multi-body dynamics model.In order to verify the structural strength and fatigue resistance of the frame,static strength and fatigue calculation and evaluation were carried out in accordance with EN13749 and UIC510-3-1994 standards.Finally,the modal structural stress method is introduced,the modal vibration shape is transformed into the modal structural stress,the equivalent structural stress time history is obtained by modal superposition,and the equivalent structural stress variation range under the line operating condition is calculated by the rain-flow counting method.The weld fatigue life of the frame structure is predicted by combining the main S-N curve.In this paper,a new technology for fatigue life prediction of welded frame welding of rail vehicles based on rigid-flexible coupled dynamics simulation is proposed.This technique can also be applied to other structures of rail vehicles to provide theory for anti-fatigue design under random loads of rail vehicle welded structures.According to this technology,this technology can also be used in other industries.