Research On Influence Of Cross-braced Arrangement On Vehicle Dynamics Performance

The three-piece bogie,because of its advantages gained popularity in industry of simple structure.convenient maintenance,excellent load balancing performance and so on is still the mainstream bogie.But the traditional three-piece bogie generally existing a problem of the lack of anti-warp stiffness value and the like of technical defects,especially that the anti-warp stiffness value significantly reduce after inclined wedge friction damper is wore,lead to the worse stability of the snake movement.In order to solve this problem,each country commonly adopt cross-braced technology to improve the bogie anti-warp stiffness and the vehicle dynamics performance of the three-piece bogie.In the process of engineering practice,because the two cross-braces are fixed together through fasteners and stress is more complex,the phenomenon that the end portion of cross-brace crack or even fracture is often happened.With the increase of axle weight and car load,working en ironment of cross-braced arrangement becomes worse.The problem about own strength and strength of the end portion must be taken seriously,it is necessary to further analysis of cross-braced arrangement's effect on the dynamics performance of the three-piece bogie,and put forward the improvement plan.In order to solve this problem,based on the theory of vehicle dynamics,SIMPACK vehicle dynamics software is applied to establish the vehicle dynamics model.The model is applied to research the cross-braced bogie,no cross-braced bogie and the modified cross-brace bogie dynamics performance when they through the curve with 60km/h balanced speed in heavy-load and tare-load condition to analyze condition of cross-braced arrangement for vehicle dynamics performance and probe into the influences which adding the wall thickness of cross-brace for it.It will provide certain theoretical basis for solving own strength for develop heavy axle weight bogie.When cross-braced bogie with the 60 km/h balance speed through the curve,wheel lateral displacement,the derailment index,wheel unloading rate,and so on are all below the safety limits,and relatively longitudinal displacement between the frames is lesser,which is 3.7 mm.After unloading cross-braced arrangement,dynamics parameters are all in a certain increase.The change of relatively longitudinal displacement is obvious in the tare-load condition because of the decrease of anti-warp stiffness value,which increases to 12mm from 2.4mm.Compared with the cross-braced bogie with adding the wall thickness and the original bogie,the dynamics performance has little change.The relatively longitudinal displacement remains at the low levels.Cross-braced arrangement can effectively improves the anti-warp stiffness of bogie.It will inhibit the relatively longitudinal displacement between frames and improve the dynamics performance of bogie through the curve.With increasing of the wall thickness of the cross-brace,it increase own stiffness and the cross-braced end joint stiffness.and does little effect on the bogie's dynamics performance ofthe curve at the same time.