Analysis of Dropper Stress in a Catenary System for a High-Speed Railway

When the pantograph slides over the contact wire at a high speed, there are cyclic stresses acting on droppers. The cyclic stresses are related with the fatigue life and fracture of the dropper. Thus, the stress calculation of the dropper is particularly important to ensure the safe operation of a train. In this paper, a simple model based on a span of five droppers is constructed. The contact wire is treated as a beam element and the vibration equation under a dynamic force is deduced. Then, the stresses are performed numerically using the finite difference method. The stress-time relationship under a dynamic force is obtained and compared with that under a constant force. The results show that there is a large shock effect during the deformation of dropper from straightening to compression and then bending. The dynamic force could cause much higher stresses than a constant force. It indicates that a dynamic force has a more significant impact on the stress value of dropper than a constant force.