Vehicle-induced Vibration Analysis Considering Nonlinearity Of Ballast Bed In Curve Section

As one of the important components of ballasted track structure,track bed has strong discreteness,which makes its mechanical properties more complicated.In the curve section,the mechanical characteristics of rail are more complex,and the effect of centrifugal force on the vehicle part can not be ignored.All the above reasons aggravate the difficulty of dynamic analysis of vehicle-ballasted track system on the curve section.In view of the above problems,based on the vehicle-track coupling dynamics and finite element method,the dynamic interaction model of vehicle-ballasted track on the curve section is established in this thesis,and the influence of the transverse resistance of track bed and the nonlinear characteristics of the curved beam element on the dynamic characteristics of vehicle-ballasted track system on the curve section are analyzed in detail.The research content of this thesis includes the following aspects:(1)A vehicle-track dynamic interaction model is established,in which the vehicle system and track structure are simulated by multi-rigid structure and finite element method respectively.In the track structure model,the geometric nonlinearity of curved beam element and the nonlinearity of track bed lateral resistance are considered in detail.vehicle-track coupling dynamics theory,the vehicle system and the ballasted-track model are integrated,and the centrifugal force when the vehicle passes the curve is considered in detail.(2)In order to solve the static deformation of the track structure with nonlinear characteristics,the incremental method and the iterative method are described in this paper,and the correctness of the above methods is verified by comparing the results of the two methods.Dynamic iteration method and cyclic calculation method are used to ensure the stability and efficiency of the results.Based on the Houbolt method,the Houbolt incremental sequence is proposed by referring to the idea of numerical integration method.In addition,this paper carries on the specific verification for the above solution method to ensure the correctness of the calculation method adopted.(3)The influence of nonlinear characteristics of curved beam element and track bed lateral resistance on static/dynamic performance of the system is compared and analyzed,and the following conclusions are drawn: the geometric nonlinear characteristics of curved beam element have great influence on static deformation of track structure,and the linear curved beam element will overestimate the static deformation of track structure;The nonlinear characteristic of track bed lateral resistance has a great influence on the dynamic response of the system,especially on the dynamic response of track structure.(4)The influence of the vehicle-ballasted track system on curved section are analyzed.The effects of track bed state,curve parameters and vehicle speed on the dynamic characteristics of the system are analyzed from the perspective of time domain and frequency domain.The dynamic analysis is carried out for the common diseases in CWR,and the running performance is evaluated at the same time,which can provide reference for engineering practice.There are 94 figures,4 tables and 61 references in the thesis.