| At present,the bogie frame of railway passenger vehicles in our country is mainly made of welded steel frame,which can reduce the weight of the vehicle.The frame is subjected to complex multiaxial fatigue loads during service,The main failure form is fatigue crack failure.With the increase of vehicle running speed,the increase of load and the expansion of frequency range,especially the complex welding joint form,the load condition of the frame becomes very bad.In the previous vehicle operation,the welded frame has exposed many fatigue reliability problems,not only affecting the normal operation of the railway,but also affecting the safety of the train.The research object of this paper is the welded frame of 209 P type passenger car bogie produced by A Company,The fatigue of the structure after crack reinforcement occurred in the joint between the transverse and the longitudinal beams is studied deeply.The main research work is as follows.(1)According to the production drawings of the 209 P bogie frame designed by A Company,this paper first establishes the three-dimensional geometric model of the frame by using SolidWorks,The model is imported into HyperMesh for gridding and pre-processing and the finite element model is generated.Finally,according to EN13749 standard,the framework is used to simulate the operating load conditions,The stress distribution under different working conditions was calculated by ANSYS,and the fatigue strength of weld seam Goodman curve in high notch stress area obtained from ORE B12/ RP17 was evaluated by using ORE B12/ RP17 in the fatigue limit diagram of steel in the study area.(2)Based on the rigid-flexible coupling system dynamics method,the flexible body model of the frame is established in HyperMesh,and then the dynamic model of the 25 G type passenger car system in the multi-body dynamics software UM is established,The other main components,such as bodywork,sleepers,spring joists,wheel sets and axle boxes,are still treated as rigid bodies,taking into account the flexibility of the frame.The vibration response of the frame is calculated by time domain integral.On this basis,the vertical load on the 1-bit two-series rocker spring seat and the transverse load on the spring seat of one-bit tied shaft box are obtained,The results show that the vehicle is in the direction of operation.(3)The fatigue life analysis method of welded frame is expounded and the fatigue life analysis method of weld is introduced in detail.Stress near or close to the material yield limit in the vicinity of a frame weld,Combined with the given S-N curves of welded joints and Palmgren-Miner linear cumulative damage criterion in IIW standard,the fatigue life of the key research area of frame is calculated by stress amplitude.On the basis of the load spectrum obtained by vehicle dynamics simulation,the fatigue life diagram obtained by FE-SAFE is used to predict and analyze the fatigue life of the frame.The fatigue life diagram can directly reflect the service life of each part of the frame.The conclusion is that the framework can be used safely and reliably during the operational and maintenance period. |
