Modelling and Monitoring of Dynamic Wheel-Rail Interaction at Railway Crossing

This dissertation aims to gain a better understanding of the dynamic wheel-rail interaction at crossings, including characterizing the wheel-rail contact behavior, evaluating the performance of crossings under traffic loads and monitoring the health condition of the structure. The first part of this dissertation focuses on an in-depth analysis of wheel-rail contact behavior and related rail degradation. An explicit 3D finite element (FE) model is developed to simulate the passage of a wheelset across a nominal crossing. The second part proposes a method to evaluate the performance of long-term serviced crossings. In the method, in-situ 3D profile and hardness measurements are conducted on a long-term serviced crossing and are used as the input for the FE modeling of dynamic wheel-rail interaction. The simulated wheel-rail contact parameters are then used to predict the distributions of plastic deformation and wear. The third part analyses the characteristic dynamic response of wheel-rail interaction at crossings. In-situ axle box acceleration (ABA) measurements were conducted on a nominal crossing with various test parameters. Thereafter, a roving-accelerometer hammer test was carried out to extract the relationship between the signature tune of the ABA and the natural frequencies of the crossing. The fourth part investigates the feasibility of the ABA system for monitoring the health condition of crossings. Information from multiple sensors was collected from both nominal and degraded crossings. By proper correlation of the gathered data, an algorithm was proposed to identify the characteristic ABA related to crossing degradation and then to evaluate the health condition of the structure.