Analysis Of Straddle Monorail Vehicle-track Beam Coupling Vibration

In recent years,China's inland urban rail transit has developed rapidly and presented the rule of system diversification.As a typical pattern,straddle monorail transit has the advantages of strong terrain adaptability,efficient use of urban space,short construction cycle and low cost,etc.It has been applied and developed in many cities at home and abroad with effectively contribution to the rapid operation of urban traffic.When the straddle monorail vehicle is operating on the bridge,coupling vibration of the vehicle and bridge will be induced by the unevenness of the track beam's surface.Excessive vibration response will reduce the strength and durability of bridge structure,and shall also significantly affect the stability of running vehicle.The dynamic performance of vehicle-bridge system with long-span road-rail dual-use cable-stayed bridge will affect the applicability of urban rail transportation.Based on the above problems,the coupling vibration analysis of straddle monorail vehicle-track beam is carried out in this thesis.The main work is as follows:(1)This thesis reviews the technical characteristics of straddle monorail,its development at home and abroad,as well as the research contents and methods of vehicle-bridge coupling vibration.The calculation principle and modeling method of multi-body dynamics are expounded.(2)Based on the multi-body dynamics theory and modeling method,a 15-DOFs vehicle dynamic model was established in SIMPACK.The finite element model of track beam bridge was built in ANSYS,which was imported into SIMPACK after substructuring to form the flexible body.The mechanical properties of running wheel,guiding wheel and stabilizing wheel were defined,and the transmission of the dynamic interaction between vehicle and track beam subsystem along with the application of surface unevenness were operated through the tire force elements,so as to form the straddle monorail vehicle-track beam spatial coupling dynamic model.(3)The reliability of the dynamic model is verified by results of dynamic field-test,and the influence factors of dynamic response of vehicle-bridge are analyzed.Research shows that the relation between the mid-span displacement response of track beam and vehicle speed is not significant,while the vibration acceleration response of track beam and vehicle body increases with higher vehicle speed.The increment of vehicle load will obviously enlarge the vertical displacement of the track beam and also reduce the vibration effect of the vehicle body.The vertical vibration and lateral deformation of track beam structure are closely related to the vertical and lateral vibration of vehicle body respectively.(4)The dynamic performance of the monorail train-bridge system was analyzed on a 468 m high-span steel truss cable-stayed bridge.It shows that the first main vibration mode of bridge is the longitudinal drift of main beam,and the transverse bending mode of the main beam appears before the vertical bending mode.The vertical dynamic effect of monorail trainbridge system is relatively weak,and it will be enhanced by increasing train operation speed and numbers of formation.For the lateral displacement of bridge,single lane operation is obviously greater than that of the double-lane.The vibration acceleration of bridge becomes larger with the increasing train speed,and the influence of double-lane operation on lateral vibration of main bridge is more obvious.When the monorail train operates on the bridge at a speed of 30 ~ 100 km/h,its riding comfort meets the requirements of corresponding code,and the vertical comfort is even better than the transverse level.