Stress Analysis At Rail Joint Using Finite Element Method

Rail joint is one of three principle weak spots of railway track. Higher train speed, heavier axle loads and greater traffic density result in more severe damage of track components at rail joint. Contact stress analysis is the base of studying the mechanism of contact fatigue damage. In this thesis, the contact stress at rail joint is studied. The results provide useful datum for the further research on the contact fatigue damage at the rail joint.The following two methods are used to analyze the contact stress in this thesis, i.e.:(1) Two-dimensional and three-dimensional static elastic-plastic finite element models of the traditional rail joint (two rails connected with two bars and six bolts) are established using the commercial finite element package ANSYS. The contact stress at the rail head is calculated. And the influences of the distance from contact point to rail end, axle load and the bolt pretension on the contact pressures, stresses, strains and deformations at rail head are studied.(2) A three dimensional dynamic elastic-plastic finite element model of the traditional rail joint with height difference is established. The ANSYS implicit and ANSYS/LS-DYNA explicit codes are coupled to simulate the contact-impact process when the wheel passes over the rail joint with height difference. The influences of train speed, axle load and height difference of rail joint on the contact stresses at rail head are taken into consideration.The conclusions resulting from wheel-rail contact static analysis are summarized as following:(1) The contact pressure and the area of contact pitch increase as the distance from contact point to rail end decreases. The contact pressure and the area of contact pitch increase with increasing the axle load.(2) Equivalent stress σ_e and maximum principal shear stress τ_max increase with decreasing distance from contact point to rail end and increase with increasing axle load.(3) Influence zone of equivalent stress and plastic zone near rail head increase with decreasing distance from contact point to rail end and increase with increasing...