8 research outputs found
A new CAE procedure for railway wheel tribological design
New demands are being imposed on railway wheel wear and reliability to increase the time between wheel reprofiling, improve safety and reduce total wheelset lifecycle costs. In parallel with these requirements, changes in railway vehicle missions are also occurring. These have led to the need to operate rolling stock on track with low as well as high radius curves; increase speeds and axle loads; and contend with a decrease in track quality due to a reduction in maintenance. These changes are leading to an increase in the severity of the wheel/rail contact conditions, which may increase the likelihood of wear or damage occurring.
The aim of this work was to develop a new CAE design methodology to deal with these demands. The model should integrate advanced numerical tools for modelling of railway vehicle dynamics and suitable models to predict wheelset durability under typical operating conditions. This will help in designing wheels for minimum wheel and rail wear; optimising railway vehicle suspensions and wheel profiles; maintenance scheduling and the evaluation of new wheel materials. This work was carried out as part of the project HIPERWheel, funded by the European Community within the Vth Framework Programme
Integrating Dynamics and Wear Modelling to Predict Railway Wheel Profile Evolution
The aim of the work described was to predict wheel
profile evolution by integrating multi-body dynamics
simulations of a wheelset with a wear model.
The wear modelling approach is based on a wear
index commonly used in rail wear predictions. This
assumes wear is proportional to Tγ, where T is tractive
force and γ is slip at the wheel/rail interface. Twin disc
testing of rail and wheel materials was carried out to
generate wear coefficients for use in the model.
The modelling code is interfaced with
ADAMS/Rail, which produces multi-body dynamics
simulations of a railway wheelset and contact conditions
at the wheel/rail interface. Simplified theory of rolling
contact is used to discretise the contact patches
produced by ADAMS/Rail and calculate traction and
slip within each.
The wear model combines the simplified theory of
rolling contact, ADAMS/Rail output and the wear
coefficients to predict the wear and hence the change of
wheel profile for given track layouts
Fatigue damage assessment of a car body-in-white using a frequency-domain approach
This work presents an application of a frequency-domain methodology developed for the fatigue damage and service life assessment of mechanical components under multiaxial random loadings. The road-induced random loadings in a virtual laboratory bench test (four post test rig) are determined using an integrated MB/FE (Multi-Body/Finite Element) analysis. A method (i.e. the variance method) based on the statistics of the observed multiaxial loadings is used to determine the critical direction. The shear stress resolved on the critical direction is then assumed as the reference loading for the subsequent fatigue analysis. A frequency-domain approach recently proposed in the literature (i.e. the non-Gaussian TB method), capable to include the load non-normality into the fatigue assessment procedure, is used to estimate the loading spectrum. A comparison between the observed and the estimated loading spectrum, extrapolated from short to longer time (e.g. the entire vehicle service life), is shown. The presented results show how the proposed methodology could be a very useful tool for the reliable and quick analysis of components under multiaxial random loadings