| With the in-depth development of China’s "the Belt and Road" construction,international railway construction is facing the problem of different gauge standards in different countries.As an important part of the set gauge railway,the set gauge railway turnout can not only meet the demand for the use of trains with different gauge on the same line,but also enable the train to achieve leaping and turning.However,there is currently no mature design theory and principle for track switches,and there is a lack of engineering precedents and research literature at home and abroad.Therefore,it is of great significance to conduct preliminary design and dynamic characteristics simulation analysis of track switches on the Alimi San Line.This thesis focuses on the turnout of the covered track railway and preliminarily designs two types of quasi meter three track covered track railway turnouts based on the design specifications for heavy-duty railway turnouts.The designed turnout has the same switch angle as the No.12 turnout.We have established a coupled dynamic simulation model for the vehicle quasi meter three track covered railway turnout,and used the multi body dynamics simulation software UM to conduct dynamic simulation research on the designed form one(meter gauge straight running,standard gauge turning)and form two(meter gauge straight running,covered gauge turning)quasi meter three track covered railway turnout;And studied the influence of turnout speed on the dynamic characteristics of two types of quasi meter three track nested railway turnouts.The main conclusions are as follows:(1)When the freight car passes through two forms of quasi meter three track railway switches laterally at an allowable speed of 50 km/h and vertically at an allowable speed of 90 km/h,the dynamic characteristics indicators such as wheel rail force,derailment coefficient,wheel load reduction rate,vehicle vibration acceleration,and rail vibration acceleration are all within the safety limit.(2)When the freight car passes through two forms of quasi meter three track railway turnout in both the straight and lateral directions,there will be an instantaneous suspension of the wheels in the frog area,causing the wheel load reduction rate to instantly increase to 1.However,the overall dynamic response index of a truck passing through a turnout in a straight direction is better than that of a truck passing through a turnout in a lateral direction.(3)The maximum values of wheel rail lateral force,vehicle lateral acceleration,and derailment coefficient when a freight car passes through a quasi meter three track covered railway turnout at the allowable speed appear in the connecting part,indicating that the curve radius is an important factor in limiting the lateral derailment speed of the freight car.(4)The speed of passing through the turnout has a significant impact on the dynamic response of freight cars when passing through the quasi meter three track turnout in both the direct and lateral directions.The freight car passes through two forms of quasi meter three line set track switches at different speeds.When the speed of the switch does not exceed 50 km/h,the maximum values of the wheel rail lateral force,vehicle body lateral acceleration,and derailment coefficient all appear in the connecting part.When the speed of the switch reaches 60 km/h,the maximum values of the vehicle body lateral force,vehicle body lateral acceleration,and derailment coefficient appear in the frog area;The maximum values of the vertical force and vertical acceleration of the vehicle body both occur in the frog area;When a freight car passes through a meter track turnout in a straight direction at different speeds,the lateral force,vertical force,and derailment coefficient of the vehicle body all show an increasing trend with the speed.After the speed reaches 90km/h,the increase is more significant,and the vehicle is more prone to derailment;The lateral acceleration and vertical acceleration of the vehicle body show a significant increasing trend with the increase of speed.(5)When the freight car passes through the frog continuously at the switch of the quasi meter three line covered track railway in Form 2(meter gauge straight running,covered track turning),the dynamic response index of the second frog area is slightly higher than that of the first frog area.The impact effect of the vehicle continuously passing through two frog areas will result in a superposition,resulting in more severe lateral and vertical vibrations of the vehicle body... |
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