Stochastic Dynamic Analysis Of Maglev Vehicle-track-bridge Coupling System

The maglev vehicle-controller-track-bridge coupling system is a complex random vibration system,which is accompanied by external input excitation and multiple random factors of system structure parameters.The coupled random vibration of the system is significant,and affects the safety and stability of the running vehicle and bridge dynamic performance.Therefore,it is necessary to carry out the stochastic dynamic analysis of maglev vehicle-bridge coupling system,and it is urgent to establish a reliable and efficient stochastic dynamic analysis method of the maglev system.So far,there are few researches on maglev vehicle-bridge coupling vibration based on random vibration theory,and the development of random vibration analysis theory of maglev rail-bridge system is relatively backward.Focusing on the core problem of coupled random vibration of the maglev vehicle-track-bridge system,this dissertation constructed a magnetic/track interaction model with an active controller and established a maglev vehicle-track-bridge random vibration analysis model based on probability density evolution theory.Research on efficient random vibration analysis method and evaluation method of driving safety and ride stability under the influence of various random factors have been carried out,and a special program for calculating the random vibration of maglev vehicle-bridge was developed.The reliability of the program was verified by the Monte Carlo method and measured data,to better reveal the characteristics of the coupled random vibration of the maglev vehiclebridge system.The thesis mainly carries out research work on the following aspects:(1)In this dissertation,an active controller of active magnetic-rail interaction model was constructed,the maglev vehicle-guideway vertical time-varying random dynamic analysis model,the maglev vehicle-guideway spatial time-varying random dynamic analysis model,and the maglev vehicle-track-bridge spatial time-varying random vibration model are established from shallow to deep.Based on the probability conservation law of the probabilistic conservative system,the probability density evolution equation of the maglev vehicle-bridge system is established.The real-time probability density function,mean value,and standard deviation of the response were solved by the time integral method and bilateral difference method.Meanwhile,a multi-time-step algorithm for probability density evolution equation solving was put forward,which can effectively solve the maglev vehicle system due to the quickly dynamic response frequency is high,change speed,usually require smaller time step to capture high-frequency feature and calculation of the response timeconsuming contradictions,improve the efficiency of the maglev calculation of random vibration.It is an important step to promote maglev vehicle-guideway coupled dynamics from deterministic to stochastic.(2)Based on the maglev vehicle-guideway time-varying coupling random model,the influence of structural parameters and multiple randomness of excitation were comprehensively considered.The representative point sets of N-dimensional random parameters were constructed by the number theory method,the Voronoi cells were employed to divide the probability space and determine the initial probability of the point sets,then the influence of random parameters,vehicle parameters,guideway parameters,controller parameters,and random irregularity on the random responses of the maglev system was studied based on the probability density evolution theory.By introducing the random vibration theory and the idea of reliability,the stochastic dynamic coefficient is proposed to describe the dynamic vibration effect caused by random factors,which effectively overcomes the problem that the traditional deterministic dynamic coefficient(such as dynamic coefficient and impact coefficient)cannot describe the discrete degree of random vibration response;The parameter sensitivity analysis of the maglev vehicle-guideway coupling system under the N-dimension random factors is carried out.(3)The 2-dimension and 3-dimension maglev vehicle-structure(guideway,track-bridge-pier)random vibration analysis program was developed,and the program was verified by Monte Carlo simulation,classical literature results and field measured data.Meanwhile,a fuzzy adaptive proportional-integral-differential(PID)controller is established,and real-time fuzzy random optimization of PID parameters is carried out based on fuzzy logic and certain fuzzy rules.Based on the idea of reliability,a random evaluation was conducted for the safety and ride comfort of the maglev train under the combined excitation of random maglev vehicle,bridge parameters,and random track irregularity.The safe speed threshold was proposed.There are 111 figures,41 tables,and 165 references.