Bio: M. Ertz is an academic researcher from Technical University of Berlin. The author has contributed to research in topics: Shakedown & Residual stress. The author has an hindex of 1, co-authored 1 publications receiving 38 citations.
TL;DR: In this paper, an approximate analytical solution for a line contact model is presented for a wheel and rail, and the increased bulk temperature of the wheel after a long period of constant operating conditions is also taken into account.
Abstract: Sliding friction between railway wheels and rails results in considerable contact temperatures and gives rise to severe thermal stresses at the surfaces of the wheels and rails. An approximate analytical solution is presented for a line contact model. The increased bulk temperature of the wheel after a long period of constant operating conditions is also taken into account. The thermal stresses have to be superimposed on the mechanical contact stresses. They reduce the elastic limit of the wheel and rail, and yielding begins at lower mechanical loads. When residual stresses build up during the initial cycles of plastic deformation, the structure can carry higher loads with a purely elastic response in subsequent load cycles. This phenomenon is referred to as shakedown. Due to the distribution of temperature, the rail surface is generally subjected to higher stresses than the wheel surface. This can cause structural changes in the rail material and hence rail damage.
TL;DR: In this paper, the running band is composed of longitudinal contact strips with various surface and subsurface morphologies, which is essential for the onset of rail squats, and this new information makes it possible to account for the entire damage mechanism of a squat defect from initiation to propagation.
TL;DR: In this article, the formation of white etching layer (WEL) by martensitic transformation in R260Mn grade pearlitic rail steel was simulated by fast heating and quenching experiments.
TL;DR: In this paper, a finite element method (FEM) was used to study thermal-elastic-plastic deformation and residual stress after wheel sliding on a rail, where the consideration of sliding contact between the wheel and the rail was restricted to a two dimensional contact problem.
TL;DR: In this paper, the effects of friction coefficient and slip/roll ratio on the wear rate and rolling contact fatigue are investigated, and frictional heating effects have been found to increase the rate of damage accumulation by ratcheting, leading to increased wear and tendency for rolling contact fatigues.
TL;DR: In this article, the longitudinal vibration phenomenon of the wheelset when stick-slip occurs is put forward and its formation mechanism is made clear innovatively, in order to study the dynamic behaviours of locomotives under saturated adhesion.
Abstract: In order to study the dynamic behaviours of locomotives under saturated adhesion, the stability and characteristics of stick–slip vibration are analysed using the concepts of mean and dynamic slip rates. The longitudinal vibration phenomenon of the wheelset when stick–slip occurs is put forward and its formation mechanism is made clear innovatively. The stick–slip vibration is a dynamic process between the stick and the slip states. The decreasing of mean and dynamic slip rates is conducive to its stability, which depends on the W/R adhesion damping. The torsion vibration of the driving system and the longitudinal vibration of the wheelset are coupled through the longitudinal tangential force when the wheelset alternates between the stick and the slip states. The longitudinal oscillation frequencies of the wheelset are integral multiples of the natural frequency of torsion vibration of the driving system. A train dynamic model integrated with an electromechanical and a control system is established to sim...