Dynamics Analysis Of Heavy-haul Railway Turnout

Nowadays,the background of railway development is high-speed passenger transport and heavy freight transport.Turnout is a weak link in track components,an important factor to determine the running speed and safety,and also an important factor to limit the capacity of railway.For heavy haul railway,large axle load and large traffic volume are its main characteristics,so there will be greater wheel-rail dynamic interaction.Excessive wheel-rail force plays a more obvious role in turnout area,which will aggravate the fatigue damage of track components.On the other hand,the shape of rail cross-section in switch area and frog area varies with the length direction of the line,reflecting the characteristics of variable cross-section of the turnout,and the interruption of the track will occur in the frog area.Therefore,the contact state of the wheel and rail in the turnout area is complex and changeable.The dynamic response of the railway turnout under heavy load condition is analyzed,and the fatigue damage law of the railway turnout is found,which can improve the turnout.The service life of the turnout is of positive significance to the maintenance and repair of the turnout.Based on the multi-body system dynamics software UM,the fixed frog turnout model No.12 and No.18 and the C80 model of 25 ton axle load freight car are established.The turnout model and the vehicle model are reasonably simplified.Firstly,this paper simulates and analyses the vehicle side reverse and straight reverse passing through fixed frog turnout No.12 and No.18.The simulation results show that the impact between wheels and rails in the switching area is mainly lateral vibration impact,while the impact between wheels and rails in the frog area is mainly vertical vibration impact.Compared with speed-up turnout and high-speed turnout,the vertical impact of wheel and rail in frog area is fierce,and the vertical force of wheel and rail is close to or higher than the vertical force limit under low-frequency conditions.Transient rail jump occurs when heavy-duty trucks pass through the turnout frog area,and the wheel load reduction rate reaches the maximum of 1.The dynamic performance of the vehicle passing through the turnout directly and backwardly is better than that of the vehicle passing through the turnout backwardly.In order to consider the following requirements:(1)Railway heavy haul can increase the speed of entering and leaving stations in order to improve the passing capacity;(2)Turnout can save land and be easily laid for construction;(3)It is economical to manufacture and maintain.This paper studies and designs No.15 fixed frog turnout for heavy haul railway.The design of turnout mainly includes the determination of turnout passing speed,the design of turnout structure and the design of turnout plane.Then the model of turnout No.15 is established in the dynamic software,and the dynamic analysis is carried out.Finally,the dynamic performances of the three turnouts are compared to verify the rationality of the design of turnout No.15.The results show that most of the dynamic performances are between turnout No.12 and turnout No.18 when the vehicle passes through turnout No.15 at a speed of 60 km/h.Individual data show that the matching of speed,curve radius and number of turnouts is relatively optimal.The dynamic performances of the vehicle passing through turnout No.15 at a speed of 80 km/h are also excellent,which shows that turnout No.15 has good dynamic performances.The design of switch is reasonable.