Research On Influence Factors Of Ride Comfort Of Straddle-type Monorail Traffic

The straddle-type monorail is different from the traditional rail transportation,the vehicle does not operate with the aid of rail,but sits directly on the special track beam.The track beam is not only the load-bearing structure of the vehicle,but also the guideline for vehicle operation.The bogies are equipped with three types of tires:running wheels,guide wheels and stabilizing wheels,all of which are rubber tires.Straddle-type monorail will have broad prospects for development in China because of its small footprint,good performance when through small radius curves and short construction period,meanwhile the rubber wheels are noise-reducing and shock-absorbing.Based on the straddle-type monorail transportation engineering in Chongqing and the relevant research results at home and abroad,the multi-body dynamics software SIMPACK and the finite element software ANSYS have been used to establish the vehicle-bridge coupling system model of straddle-type monorail in this paper.Then perform a dynamic analysis on the model,study the influence factors of ride comfort,put forward the control criteria of those factors and measures to improve the ride comfort of straddle-type monorail.The main contents are as follows:Firstly,the development status of straddle-type monorail transportation system and the research results of vehicle-bridge coupled vibration of rail transit are introduced,multi-body dynamics research methods and basic concepts are summarized and the components of the multi-body system of monorail vehicle are analyzed.Secondly,a 38-DOF straddle-type monorail vehicle model was established based on SIMPACK.A cornering model was established for walking wheel,while the guide wheel and the stabilizing wheel were simplified to lateral force that move with the vehicle.Then combined vehicle models into a four-car group train model.Thirdly,a 3×22m double-line simply supported beam bridge model was established based on ANSYS.Sub-structure analysis of the bridge model was carried out and the bridge model was imported into vehicle multi-body system as flexible track through the finite element interface program FEMBS of SIMPACK.Wheel-rail contact points are defined to realize the coupling of vehicle and bridge.Trigonometric series method was used to the track irregularities,and the track irregularities were transformed into the track beam surface irregularities,which were applied to the straddle-type monorailtraffic system as excitation source.Finally,the ride comfort evaluation standards of straddle-type monorails were proposed,dynamical simulation of the coupling system was finished in SIMPACK.The effects of vehicle speeds,pier height,track irregularities and load on ride comfort of straddle-type monorail were discussed separately,the limit of each influencing factor was given.It is suggested that the stiffness of the bridge could be improved by increasing the thickness of diaphragm beam or the height of track beam appropriately and the tyre dampling of cars could be improved appropriately,thereby the ride comfort of straddle-type monorail can be improved.The results obtained in this paper can provide a certain reference for the evaluation of bridge dynamic performance and train operation performance of straddle monorail traffic,and it is of great significance to ensure the ride comfort of straddle monorail traffic.