Investigation of Effective Parameters on Impact Stress in a Rail Joint and its Comparison with Contact Stress in a Dynamic Condition

Rail joints are one of the most sensitive and vital areas of a rail, and they playa determinant role in railway tracks. Therefore, impact stress analysis that simulates when a train’s wheels pass over the tracks is one of the most basic requirements in this field. In this study, stress and displacement over the two ends of rails in a rail joint have been investigated, along with their effective parameters. Because of the complexity of this in terms of solving the dynamic analysis problem when the wheel passes over the rails and their connections, in this study an LS-DYNA solver has been implemented that allows explicit solving. In this research, the effect of axial load and speed as two important parameters has been examined, and the ratio of contact force to axial load has been computed. In addition, the effect of distance of the rail gap on the impact stress has been studied. These studies have been conducted for rail profiles that are used in Iran’s domestic rail industry (UIC60). Results show that by increasing the axial load there is an increasing the imported stress to the head rails, while by increasing the speed there is no remarkable change in stress on the head rails. To carry out this investigation, a factor has been introduced that is termed ‘impact stress factor’. This is equal to 1.435 and shows the ratio of impact stress in the rail joint to the contact stress. The results also show that the contact force in the contact area is about 3 times that of the axial load. Investigation of the rail gap distance shows that by increasing the gap distance, the impact stress is increased, but the rate decreases.