Ballastless Track System Reduction And The Research Of Nonlinear Coupling Method

In recent years, the rapid development of high speed railway not only brings convenience to people for travel, but also brings huge economic benefits to the society. With the continuous improvement of train speed, the high-speed railway safety problem increasingly highlight, thus it is of great significance to study the train structural damage and failure caused by vibration. The main method of the current research is to build a dynamic model of high-speed train coupling system. As a supporting part of the coupling system, the rail system has important influence on railway traffic safety. The system consists of multiple complex parts, mathematical model is not accurate enough to reflect distribution characteristics of the vibration response in time and space domain. However, accurate finite element coupling model with a large number of meshes and degrees of freedom would lead low computational efficiency. In this paper, several model reduction methods were applied on the parts of balastless track system, after which the reduced parts were assembled into system.This paper first introduces several common model reduction methods, compares the advantages and the disadvantages and Guyan and IRS reduction methods were chosen to be used. Also, this paper introduces nonlinear coupling theory.HYPERMESH and ABAQUS were chosen to establish the rail and slab FEM model and their mass matrices and stiffness matrices were extracted. By selecting the master nodes and master degrees of freedom of rail and slab respectively, Guyan and IRS reduction methods were used to establish the rail and slab reduced model and programming was done. Also, the evaluation index of the reduced model precision was introduced, then modal analysis and dynamic response analysis of the original model and the reduced model were conducted. After comparing the precision of different methods for computation of the natural frequency, modes and dynamic response, the reduction method of high er precision was selected. The results show that IRS reduction method is more accurate than Guyan reduction method, which would be applied on balastless track system reduction.The rail and slab finite element coupling model was established. According to the mass and stiffness matrix of the rail and slab which were obtained by IRS reduction method, the rail and slab nonlinear coupling mathematic model was established and nonlinear coupling programming was done based on wilson ?. Dynamic response analysis of the original coupling model and the coupling model after reduction were conducted respectively and the results were compared which show that the dynamic response of the system before and after the reduction are consistent, and the calculation efficiency is greatly increased after reduction. Therefore, the low-order coupling model after the reduction could replace the original complex higher order finite element cou pling model.