REVIEW ON THE FATIGUE BEHAVIOR OF THE WHEELS OF RAILWAY VEHICLES IN CONTACT WITH RAIL

Abstract

Rail transport is essential to the EU's strategy for a more sustainable transport sector, economic and social cohesion and connecting Europeans at and between each Member State. EU trend is to support the railway sector as a clean, main mode of transport at European level. The European rail system carries around 1.6 billion tones of freight and 9 billion passengers each year. The railway sector has a substantial contribution to the EU economy, directly employing over 1 million people. With the technological evolution of railway vehicles, it is important to focus on safety issues. Wheels are one of the most critical components of railway vehicles, as their failure can lead to derailment. Therefore, an exact project on the control of the problem of wheel fatigue and knowledge of the effective parameters on their life, can improve the life of the whole structure. Due to the fact that the nature of the loads applied to the wheels is repeated, fatigue is  very common mechanism of damage that can occur in several ways, such as: nucleation and growth of fatigue cracks, spalling, shelling, and so forth. The main sources of these phenomena are the rolling contact loads, the thermal loads between the wheel-rail and the wheel-brake block, created in the braking phase, the presence of structural defects in the wheel material; it follows that they cannot be omitted in a rigorous design. Increasing of speed aggravates these factors and exacerbates the problem of thermal fatigue of the wheels. In this paper we present a series of studies that focused on the wear of the wheels of railway vehicles in contact with the steering track (rail) to fatigue.