Research And Optimization Of The Dynamic Characteristics Of Heavy-duty Trains And Subgrades Under Vertical Impact Conditions

Heavy haul trains have been paid much attention by all countries in the world because of their low cost,high efficiency and large transport capacity.With the increase of transportation demand,the axle load of heavy haul trains is also increasing,and the shaft spacing is constantly shrinking.The increasion of axle load will increase the railway subgrade by dynamic load amplitude,and the reduction of the axial gap will make the dynamic load depth increased.The amplitude of dynamic loads increases with the depth of action will produce more serious damage on the subgrade damage.This paper mainly studies the dynamic response and optimization of the train underframe and the railway subgrade when the heavy load train is subjected to the vertical impact load.Because the heavy load train is a complex nonlinear system,it is necessary to establish an accurate model of train and Subgrade.Firstly,introduces the theory of finite element method and numerical calculation method,introduces the application of elastic theory and plastic model of friction contact theory and the finite element method in rock and soil mechanics.Secondly,the numerical theory analysis method is used to study the characteristics of the vertical impact load,and set up the dynamic model of the train and the subgrade.In this paper,the dynamic response of the train and the subgrade under the impact of the vertical impact load is studied.Then,drawing on the support mode of freight cars and highway trucks,the hydraulic support of rail is designed and the dynamic characteristics are studied.On the basis of rail hydraulic support,the structure optimization is carried out,and two other supporting modes are designed:ballast hydraulic support and connection support between front and rear carriages,and dynamic characteristics are studied respectively.Finally,an approximate model of railway subgrade is established,and the sensitivity analysis of all layers of materials is carried out.And the parameters of railway subgrade are optimized to reduce vertical displacement of roadbed.