Wheel and Rail Profile Design
Multi-Objective Optimisation of the Wheel-Rail Interface Using Dynamic Simulations to Minimise Wear and Rolling Contact Fatigue
Time: Fri 2025-12-12 09.00
Location: F3, Lindstedtvägen 26
Video link: https://kth-se.zoom.us/j/64897602106
Language: English
Subject area: Vehicle and Maritime Engineering
Doctoral student: Elham Khoramzad , Fordonsteknik och akustik
Opponent: Professor Jens Nielsen,
Supervisor: Carlos Casanueva, ; Saeed Hossein-Nia, ; Sebastian Stichel,
QC 251118
Abstract
The interaction between wheels and rails is a key determinant of railway performance, safety, and maintenance costs. Degradations such as wear and rolling contact fatigue originate from the complex mechanical and dynamic processes at the wheel-rail interface. With increasing traffic demand, higher axle loads and greater operational speeds, these degradations intensify and lead to more frequent and costly maintenance. This thesis addresses these challenges by developing and applying multi-objective optimisation techniques for the design of wheel and rail profiles, with the overall aim of reducing damage rates and extending service life.
A refined tangential contact modelling framework is introduced that incorporates a slip velocity dependent friction coefficient to improve the estimation of traction, wear and rolling contact fatigue. An index is developed to estimate the likelihood of curve squeal noise on specific track sections, thereby supporting noise mitigation strategies.
The performance of two multi-objective optimisation algorithms, namely NSGA II and MOPSO, is analysed under identical conditions to provide insights into their suitability for profile optimisation. Practical implementation aspects, including grinding limitations, are explicitly considered to ensure that the optimised rail profiles are feasible for real-world application.
The optimisation methodology is applied to both passenger and heavy haul contexts. For a broad-gauge heavy haul system, novel techniques are presented for optimising high and low rail profiles in curves as well as multiple profiles for tangent track. Furthermore, a systematic approach is proposed for the integrated optimisation of wheel and rail profiles on a dedicated heavy haul line, taking into account the requirements of the infrastructure owner.
The findings demonstrate that optimised wheel and rail profiles can substantially reduce wear and fatigue, while maintaining vehicle stability and steering performance, extending component lifespans and lowering maintenance demands. The contributions of this thesis provide both methodological advances and practical solutions for railway operators and infrastructure managers, supporting the sustainable development of railway systems under modern operating conditions.