Coupled simulation of vehicle dynamics and aerodynamics

Abstract

The influence of wheel and rail profile shape features on the initiation of rolling contact fatigue (RCF) cracks is evaluated based on the results of multi-body vehicle dynamics simulations. The damage index and surface fatigue index are used as two damage parameters to assess the influence of the different features. The damage parameters showed good agreement to one another and to in-field observations. The wheel and rail profile shape features showed a correlation to the predicted RCF damage. The RCF damage proved to be most sensitive to the position of hollow wear and thus bogie tracking. RCF initiation and crack growth can be reduced by eliminating unwanted shape features through maintenance and design and by improving bogie tracking.

The effect of rolling contact fatigue mitigation measures on wheel wear and rail fatigue

“…It is expected that the hollow wear band would remain the same if this result is extrapolated to a bogie with softer primary suspension. All the worn profiles show false flange formation and according to the findings of Fröhling et al [11] and Spangenberg et al [6] this worn shape of the wheel is undesirable since it is more conducive to RCF initiation.…”

“…These elements are standard in the VI-Rail Freight Toolkit add-on. The accuracy and validity of this model was presented by Spangenberg et al [6].…”

“…The progression from the wear regime, where rail side wear and wheel flange wear is dominant, to the stress regime, where RCF is dominant, has been discussed by Tournay and Mulder [4]. RCF develops due to contact between the so-called false flanges of the hollow worn wheels and the gauge corner and field side of the rails [5,6]. The adverse contact conditions resulting from the false flanges are shown in Figure 1.…”

“…According to the shakedown diagram of Johnson [10] this will result in a reduction of RCF initiation. The relationship between hollow wear and RCF initiation was further investigated by a number of authors [5,6,11] and [12]. These authors highlighted the relationship between hollow wear and surface-initiated RCF cracks.…”

“…Tournay and Mulder [4] found that hollow worn wheels cause contact beyond the hollow wear band increasing the risk of RCF initiation. The severity of RCF damage can be linked to the hollow worn wheel shape [6,11]. It is therefore important to spread the wear across the wheel tread to maintain its original shape as far as possible and limit false flange formation.…”