A finite element thermomechanical analysis of the development of wheel polygonal wear

Polygonal wear is a type of damage commonly observed on the railway wheel tread. It induces wheel-rail impacts and consequent train/track components failure. This study presents a finite element (FE) thermomechanical wheel-rail contact model, which is able to cope with the three possible generation and development mechanisms of polygonal wear...

A two-dimensional ordinary state-based peridynamic model for surface fatigue crack propagation in railheads

Based on ordinary state-based peridynamic theory, a 2D peridynamic model has been established to investigate fatigue crack propagation in railheads. The proposed model is verified in terms of rail deformation under a quasi-static load and the ductile material-related fatigue failure model. Good agreements have been achieved between a finite...

Comparisons between beam and continuum models for modelling wheel-rail impact at a singular rail surface defect

A singular rail or wheel surface irregularity, such as a squat, insulation joint or wheel flat, can cause large wheelrail impact force. Both the magnitude and frequency content of the impact force need to be correctly modelledbecause they are closely related to the formation, deterioration and detection of such irregularities. In this paper,we...

Design, calibration and validation of a wheel-rail contact force measurement system in V-Track

An innovative downscale test rig called V-Track has been constructed for wheel-rail contact experiments under impact loading conditions. In this paper, a force measurement system termed a dynamometer was developed in V-Track to measure the wheel-rail contact forces. The dynamometer consists of four 3-component piezoelectric force sensors and...

An investigation into the formation of squats in rails: modelling, characterization and testing

Rolling contact fatigue (RCF) is an important form of damage in wheels and rails that typically has surface and subsurface cracks. Squats are one of the major RCF defects that occur in the running band of rails and can create high dynamic forces and cause rail fracture if they are not detected and treated in time. In the current research, three...

Influence of wheel polygonal wear on wheel-rail dynamic contact in a heavy-haul locomotive under traction conditions

For a heavy-haul locomotive within a wheel repairing period, wheel polygonal wear with different operating mileages is obtained by field testing. The test results show that the maximum radial runout of the wheel can increase to 0.87 mm and accompany with the typical damage of wheel tread shelling. Taking the wheel polygons as input excitation...

A numerical study on waves induced by wheel-rail contact

Recent finite element (FE) simulations have revealed the generation and propagation of waves in rail surfaces induced by wheel-rail frictional rolling. These waves have rarely been addressed in the literature. This paper presents an in-depth analysis of these waves, aiming to give new insights into the contact mechanics, a research area in...

Numerical modeling of dynamic frictional rolling contact with an explicit finite element method

The modeling of dynamic frictional rolling contact is crucial for accurately predicting behavior and deterioration of structures under dynamic interactions such as wheel/rail, tire/road, bearings and gears. However, reliable modeling of dynamic frictional rolling contact is challenging, because it requires a careful treatment of friction and...

Numerical modeling of wheel-rail squeal-exciting contact

Complex frictional rolling contact and high-frequency wheel dynamic behavior make modeling squeal greatly challenging. The falling-friction effect and wheel mode-coupling behavior are believed to be the two main mechanisms that generate unstable wheel vibration and the resulting squeal noise. To rigorously consider both mechanisms in one...

Thermomechanical analysis of the wheel-rail contact using a coupled modelling procedure

This research presents a coupled thermomechanical modelling procedure for the wheel-rail contact problem and computes the flash-temperature and stress-strain responses when thermal effects are present. A three-dimensional elasto-plastic finite element model was built considering the wheel-track interaction. When the wheel is running on rail,...

Long-Term Behaviour of Railway Crossings: Wheel-Rail Interaction and Rail Fatigue Life Prediction

Railway turnouts are important components of railway infrastructure as they provide flexibility and guidance to the rail traffic. Because of geometrical discontinuities in the crossing area of the turnouts, high impact forces due to passing wheels acting on the crossing nose can occur. In the field, severe rail damage problems are found in...

Development of a New Downscale Setup for Wheel-Rail Contact Experiments under Impact Loading Conditions

A new downscale test rig is developed for investigating the contact between the wheel and rail under impact-like loading conditions. This paper presents the development process of the setup, including review and synthesis of the potential experimental techniques, followed by scalability, mechanical and operational analysis of the new setup. The...

Modelling of non-steady-state transition from single-point to two-point rolling contact

By considering real wheel and track geometry and structures, as well as their coupled interaction, an explicit finite element method is applied to simulate the transition of wheel–rail rolling from single-point tread contact to two-point tread-flange contact. The evolutions of the contact position, stress magnitude and direction, adhesion–slip...

The Wheel-Rail Contact Problem in Vehicle Dynamic Simulation: Modeling of Train-Turnout Interaction

One of the major costs incurred by railway companies is the maintenance of turnouts.This situation occurs because the large dynamic forces between the wheels of a train and the rails of a turnout cause excessive wear, rolling contact fatigue and rapid degradation of other components. A thorough understanding of the dynamic interaction between a...

Performance Optimised Geometry of Railway Crossings: Design and Implementation

The paper presents an optimisation procedure for improvement of crossing performance by adjusting the cro sing (including the wing rail) geometry. The improvement of the crossing performance is achieved by reducing the normal contact pressure and wear index, while shifting the location of the wheel impact (fatigue area) along the crossing. By...

Computation of the flash-temperature at the wheel-rail contact using a 3D finite element model and its comparison with analytical methods

The coupled mechanical–thermal behaviour of wheel and rail materials under rolling contact is studied to determine the temperature rise due to the frictional heat. The wheel–rail frictional rolling contact problem is solved using the three–dimensional finite element (FE) method. The FE model considers the wheel tread–rail top contact with...

Low Adhesion in the Wheel-Rail Contact

Adhesion, or adhesion coefficient, is given by the ratio of the longitudinal tangential (i.e., braking or traction) force over the normal force at the wheel-rail contact. The tangential force that a braking or tractive railway wheel can exert on a rail is limited by the friction coefficient available between the surfaces in contact for a given...

An inverse shape design method for railway wheel profiles