| 1. |
- Bernal, Esteban, et al.
(författare)
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Friction-Slip Curves - The Pathway From Twin-Disc Tribo Measurements To Full-Scale Locomotive Multibody Simulations
- 2022
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Ingår i: PROCEEDINGS OF 2022 JOINT RAIL CONFERENCE (JRC2022). - : AMER SOC MECHANICAL ENGINEERS.
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Konferensbidrag (refereegranskat)abstract
- Locomotive multibody simulations are commonly used as a cost-effective tool to study, energy efficiency, wheel-rail wear, rolling contact fatigue, etc. The accuracy of the wheel-rail contact forces from multibody simulations depends on the correct modelling of the friction conditions. The friction coefficient is a function of the slip velocity, and it is influenced by several tribological parameters including, for example, material mechanical properties, environmental conditions and the presence of third body layers that vary spatially and temporally along the track. In most cases, generic friction-slip curves obtained from publications and public reports are used as inputs to the wheel-rail contact model in the locomotive simulations, as direct friction measurements using full-scale experimental set-ups are generally cost-prohibitive. A pathway to produce friction-slip curves from tribo-machine friction measurements is proposed in this paper. The pathway involves manufacturing discs from actual wheel and rail material samples to measure the traction coefficient at a spectrum of slip set points using a twin-disc tribo-machine. The tribo-machine results are scaled to be used in a locomotive multibody model that uses the modified Fastsim and a traction system co-simulation approach. Two friction curves for wet and dry conditions are processed and exemplified in a dynamic model.
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| 2. |
- Bernal, Esteban, et al.
(författare)
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Prediction of rail surface damage in locomotive traction operations using laboratory-field measured and calibrated data
- 2022
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Ingår i: Engineering Failure Analysis. - : Elsevier BV. - 1350-6307 .- 1873-1961. ; 135
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Tidskriftsartikel (refereegranskat)abstract
- Rail damage prediction is a complex task because it depends on numerous tribological parameters and the dynamic conditions produced by the vehicles operating at different speeds and configurations. Shakedown maps and Whole-Life-Rail-Model/T-Gamma have been used to predict rail damage, but they involve assumptions that may reduce their accuracy. This paper proposes a simulation modelling method to predict rail surface damage based on a locomotive digital twin, calibrated shakedown maps and friction measurements. The method improves the accuracy of rail damage predictions by including slip-dependent friction characteristics, co-simulation of locomotive traction mechatronic system and the mechanical properties of the wheel and rail materials measured through tensile tests. A set of operating conditions are simulated on a high-performance computing cluster, with stress results being post processed into calibrated shakedown heatmaps. The method clearly indicated the influences of the different operating conditions on rail damage for specific combinations of wheel-rail materials and vehicle-track configurations.
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| 3. |
- Wu, Qing, et al.
(författare)
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Heavy haul rail/wheel wear and RCF assessments using 3D train models and a new wear map
- 2024
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Ingår i: Wear. - : Elsevier BV. - 0043-1648 .- 1873-2577. ; 538-539
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Tidskriftsartikel (refereegranskat)abstract
- Wear and Rolling Contact Fatigue (RCF) on wheels and rails are influenced by relative motions between the studied rail and wheel pair, and therefore influenced by train dynamics. Wear and RCF assessments using a train dynamics approach provide more accurate and comprehensive results comparing with conventional assessments that often do not consider train dynamics. In addition, considering material property differences, currently available rail wear maps are not able to accurately describe the wear performance of materials that have significantly different properties. This paper presented a method for rail/wheel wear and RCF assessments using 3D train dynamics models. The use of train models allows the consideration of coupler forces, traction, and brakes during the assessment. Wear assessments were conducted by using an in-house rail wear map model developed from the twin disc wear machine at the Centre for Railway Engineering (CRE). The new rail wear map was developed by using the AS 60 rail material (hardness 340 HB). The results indicated that the methods proposed in this paper could be used for rail/wheel wear and RCF assessments. Traction/braking forces and coupler lateral forces had evident influences on wear and RCF assessment. Different wear maps were also shown to have significant influences on the wear rate results.
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| 4. |
- Wu, Qing, et al.
(författare)
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RAIL/WHEEL WEAR AND RCF ASSESSMENTS USING 3D TRAIN MODELS AND A NEW WEAR MAP
- 2022
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Ingår i: CM 2022. - : International Conference on Contact Mechanics of Wheel / Rail Systems. ; , s. 217-222
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Konferensbidrag (refereegranskat)abstract
- Wear and Rolling Contact Fatigue (RCF) on wheels and rails are influenced by relative motions between the studied rail and wheel pair, and therefore influenced by train dynamics as well. Wear and RCF assessments by suing train dynamics provide more accurate and comprehensive results. In addition, considering material property differences, previous rail wear maps may not be able to accurately describe the wear performance of materials that have significantly different properties. This paper presents a method for rail/wheel wear and RCF assessments using 3D train dynamics models. The use of train models allows the consideration of coupler forces, traction, and brakes during the assessment. Wear assessments were conducted by using an in-house rail wear map model developed for a twin disc wear machine at the Centre for Railway Engineering (CRE). The new rail wear map was developed by using the AS 60 rail material. Results show that the older BS11 rail material wear rate regimes and transitions are evidently different to the wear behaviour measured for AS60 rail material.
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