Dynamical Simulation Of High Speed Vehicle Derailment And Its Nonlinear Dynamical

For breadth of China's inland and a large population, high-speed railway efficient and fast mode of transport are most conducive to solving a large-scale population movements. High-speed railway development can stimulate economic and trade exchanges between cities along the route, which marks a national scientific and technological development level and ability of independent innovation.High-speed railway is a breakthrough and challenge of conventional railway. Due to increase of vehicle's speed, wheel-rail dynamic problems stands out, which not only affect the passenger's comfort, but also cause vehicle to derail incidents. High-speed vehicle derailment will cause more casualties and property losses. Because of the strong dynamics behavior and coupling behavior between wheel and rail, derailment under high-speed and low-speed conditions is very different. For the current, high-speed dynamic derailment research is still in the initial stage. Therefore, study on high-speed vehicle derailment is immediate. In this paper, high-speed derailment behavior of vehicles is carried out. The suitable model for the analysis of high-speed vehicle derailment is developed and high-speed derailment of vehicle dynamics simulation system is worked out to study the derailment behavior, nonlinear vehicle dynamical behavior and other issues.Derailment is extremely dynamic behavior of vehicle. In the process of derailment, the movement state of wheelset is very rich and there is a complex wheel-rail contact mode. It needs to establish suitable and accurate model for the analysis of wheel-rail derailment. For the wheel-rail contact geometry model, the improved trajectories algorithm is used to solve three-dimensional of wheel-rail contact and different contact states of wheel-rail contact geometry parameters. For wheel-rail creep force model, by analyzing the common creep force model is not suited to creep force calculation on derailment, the new improved O. Polach model is used to calculate creep force of the derailment. For the wheel-rail normal force model, according to the division of wheel-rail contact zone, in the flange contact area finite element software LS-DYNA is used to accurately calculate wheel-rail contact normal force. By comparing the results with the Hertz theory, proposed by correction factor to amend the Hertz contact theory in the flange area of wheelset. The model high-speed vehicle dynamics considers of non-linear factors of the vehicle suspension system and the changes of coefficient of friction because of the speed and the creep. Above all, set up 31 degrees of freedom model of vehicle track coupling dynamics on derailment.Simulation is an important tool to study on derailment. Based on high-speed vehicle track coupling dynamics model, high-speed derailment of vehicle dynamics simulation system is developed. The overall structure of the simulation system and the process of key wheel-rail contact subsystem are given. By analyzing the geometry characteristics of the climb derailment phase and wheel-rail critical collisions speed, a pre-derailment state in two critical conditions is proposed and the algorithm of derailment subsystem is given. Flow calculation of high-speed vehicle dynamic simulation system is designed. Based on high-speed vehicle dynamic simulation system, a dynamic climbing derailment and impact derailment is carried out and the key factors affecting derailment is proposed. The simulation system gives derailment boundary conditions under different parameters and safe driving conditions. The cause of derailment accident is analyzed into three categories and the appropriate preventive measures of each category are given.The role of non-linear factors in high-speed vehicle dynamics is more obvious, which needs to improve non-linear vehicle dynamic analysis. Wheelset is a key component for high-speed vehicle, the kinetic equation of high-speed wheelset is established for calculation and analysis of the wheelset stability. Identification algorithms on analysis the different Hopf type are researched. During the derailment of the process, wheel-rail collisions and the rail surface irregularity influence vehicle nonlinear dynamic behavior is studied. After that, plot the whole bifurcation diagram of the vehicle systems. The wheelset may induce to impact derailment in the non-linear instability. The nonlinear characteristics of impact derailment and its prediction and evaluation method is given.In order to ensure that the simulation results, verify the reliability of dynamical simulation the vehicle through Manchester Benchmark and general vehicle dynamics software, Adams / rail. According to Qin Shen line test reports, verify the simulation system on vehicle dynamic behavior in a straight and curve lines. As the vehicle nonlinear dynamics testing and derailment test is difficulty, by comparing the existing vehicle roll-vibration test report, verify the vehicle nonlinear dynamics behavior and derailment. Finally, Combined with the foreign derailment accident report, identify the main reason for the dynamical derailment accident and calculate the two-vehicle connectivity dynamics model.