| Plat-type ballastless track,with its outstanding advantages of high stability,smoothness,durability,low operation and maintenance workload and long service life,has gradually been widely promoted and applied in developed countries around the world.Under the call of our country,the Ministry of Railways is actively developing the slab track structure which conforms to the geological conditions of our country.Plate-type ballastless track structure has been widely used in the planning of new railway network.It can be seen that plate-type ballastless track has a very broad development prospect in China.Therefore,it is of great significance to improve the theoretical research on mechanical characteristics of plate-type ballastless track for China’s vision of building world-class high-speed railway.On the basis of comprehensive literature research,this paper takes CRTSⅡ slab track structure as an example,and theoretically analyzes the mechanical characteristics and dynamic response of slab ballastless track structure based on statics and dynamics,which is of great significance to the design and application of slab ballastless track engineering in China.The main research contents of this paper are as follows:(1)From static aspect,a two-layer elastic foundation beam model is established based on Winkler’s hypothesis.The rail and longitudially connected rail plate are regarded as upper beam and lower beam respectively,and the equilibrium differential equation is established.Secondly,the train load is simplified as the distributed load acting on the beam.By using the initial parameter method and introducing the "pan-Крылов function",the analytical expressions of the displacement and internal force of the rail(upper beam)and rail plate(lower beam)under the load are obtained.Finally,the finite element model is established by using large ANSYS software,and the same working conditions are simulated numerically.The accuracy and reliability of the analytical solution are verified by comparing the numerical solution with the analytical solution(2)From dynamic aspect,firstly,based on Winkler’s hypothesis,the dynamic model and differential equation of dynamic balance of beam on elastic foundation with double layers are established.Secondly,Heaviside step function was introduced to simulate the wheel load of em US on track as arbitrary length distribution load in one-dimensional direction.The forced vibration equations of upper and lower beams were obtained based on the mode superposition method,and the analytical solution of dynamic response of beam system on double layer elastic foundation was obtained by using Duhamel integral.The finite element model was established by using large finite element software ABAQUS and VS,and the numerical solution and analytical solution of the same example were compared.Finally,the dynamic responses of rail(upper beam)and rail plate(lower beam)under given motion parameters and fixed structural parameters are obtained,and the value range of each structural parameter at 400 km/h is analyzed.The reference can be offered to the field in designing engineering and and putting into practice when they are slab ballastless track structures or related elastic layered structures in this research. |
