Research On Dynamic Interaction Of Straddle Type Monorail Vehicle And Track Beam

An analytical model of dynamic responses for the coupled system of straddle type monorail beam and vehicle was established in this dissertation. The nonlinear contact relations between tires and track, the cornering characteristics of all the tires, and the case of tire-track separation were taken account in this model. Based on this model, cross-wind load was added and the dynamic model of vehicle-beam-wind system was established. This dissertation is mainly concerned with the following studies:(1) The structure, vibration characteristics and cornering characteristics of the tire were analyzed, based on which, the mechanics model for the running tire, steering tire and stabilizing tire was established. In the model, the nonlinear vibration characteristics of the tires were analyzed, the effects of track beam vibration on the cornering characteristics and longitudinal slide turning of all the tires were taken account, and the effects of tire-track separation factor on the dynamic responses of vehicle-beam system were also taken account.(2) The dynamic model of monorail vehicle with15-degrees-of-freedom was established and its vibration differential equations were derived by using D’Alembert principle. Track beam was idealized as Euler beam and its vibration differential equation was derived. Based on the vehicle/beam interaction relationship, the governing equations of motion for the coupled system of straddle type monorail beam and vehicle were derived by applying a modal superposition technique to the beam only. According to the theory presented in this dissertation, a computational program for analyzing the dynamic responses of beam and vehicle was developed by Visual Fortran6.5and listed a detailed process.(3) The simply-supported monorail PC beam (Z206-25beam) in the section of the straddle type monorail transit from Niujiaotuo to Liziba in Chongqing City was selected as the research model. Then, the whole histories of the straddle type monorail train passing through the beam were calculated. The dynamic responses of the beam and vehicle under different train speed were obtained. The calculated results of dynamic responses were compared with the test data, and the correctness of the model established in this dissertation and the computing program were partially validated. The reasonable pre-pressure value range of steering tire and stabilizing tire was also studied.(4) The comparison was made between the model presented in this dissertation and the other model used frequently. The dynamic responses of the beam and vehicle under different train speed of these models were calculated, the results of which were compared, and the applicability of these models was studied. The effects of cornering characteristics of the tires on the dynamic responses of vehicle-beam system were also studied.(5) Based on the model, cross-wind load was added and the dynamic model of vehicle-beam-wind system was established. The lateral dynamic responses of this system were studied at different driving speeds and different wind speeds, and the cross-wind load contributions to the dynamic responses of the beam and vehicle was studied.Major conclusions can be drawn as follows:The model established in this dissertation can generally reflect the real interaction relationship between vehicle and track beam, and can be applied to the design and calculation of the similar track beam. Above10kN pre-pressure, steering tires and stabilizing tires can roll cling to the track when the wind speed less than15m/s. Generally, the response amplitudes of the beam and vehicle increase as the train speed and wind speed increase. The train can safely and comfortably go through the beam when the train speed is less than80km/h and the wind speed is less than20m/s. The effects of running tire cornering characteristics on the dynamic responses of the beam and vehicle are greater than those of the steering tire and stabilizing tire. The nonlinear characteristics should be considered when the tire has a greater deformation.