| 1. |
- Abbasi, Saeed, 1973-, et al.
(författare)
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Temperature and Thermoelastic Instability at Tread Braking Using Cast Iron Friction Material
- 2013
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Ingår i: Wear. - : Elsevier BV. - 0043-1648 .- 1873-2577. ; 314:1–2, s. 171-180
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Tidskriftsartikel (refereegranskat)abstract
- Braking events in railway traffic often induce high frictional heating and thermoelastic instability (TEI) at the interfacing surfaces. In the present paper, two approaches are adopted to analyse the thermomechanical interaction in a pin-on-disc experimental study of railway braking materials. In a first part, the thermal problem is studied to find the heat partitioning between pin and disc motivated by the fact that wear mechanisms can be explained with a better understanding of the prevailing thermal conditions. The numerical model is calibrated using the experimental results. In a second part, the frictionally induced thermoelastic instabilities at the pin-disc contact are studied using a numerical method and comparing them with the phenomena observed in the experiments. The effects of temperature on material properties and on material wear are considered. It is found from the thermal analysis that the pin temperature and the heat flux to the pin increase with increasing disc temperatures up to a transition stage. This agrees with the behaviour found in the experiments. Furthermore, the thermoelastic analysis displays calculated pressure and the temperature distributions at the contact interface that are in agreement with the hot spot behaviour observed in the experiments.
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| 2. |
- Abbasi, Saeed, et al.
(författare)
-
Temperature and thermoelastic instability of tread braking friction materials
- 2012
-
Ingår i: Proceedings 9th International Conference on Contact Mechanics and Wear of Rail/Wheel Systems. ; , s. 606-607
-
Konferensbidrag (refereegranskat)abstract
- Braking events in railway traffic often induce high frictional heating and thermoelastic instability (TEI) at the interfacing surfaces. In the present paper, two approaches are adopted to analyse the thermomechanical interaction in a pin-on-disc experimental study of railway braking materials. In a first part, the thermal problem is studied to find the heat partitioning between pin and disc motivated by the fact that wear mechanisms can be explained with a better understanding of the prevailing thermal conditions. The numerical model is calibrated using the experimental results. In a second part, the frictionally induced thermoelastic instabilities (TEI) at the pin-disc contact are studied using a numerical method and comparing them with the phenomena observed in the experiments. The effects of temperature on material properties and on material wear are considered. It is found from the thermal analysis that the pin temperature and the heat flux to the pin increase with increasing disc temperatures up to a transition stage. This agrees with the behaviour found in the experiments. Furthermore, the thermoelastic analysis displays calculated pressure and the temperature distributions at the contact interface that are in agreement with the hot spot behaviour observed in the experiments.
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| 3. |
- Barkan, C., et al.
(författare)
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SPECIAL ISSUE ON HEAVY HAUL AND INNOVATIVE DEVELOPMENT
- 2010
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Ingår i: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit. - 0954-4097 .- 2041-3017. ; 224:F5, s. I-II
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Tidskriftsartikel (refereegranskat)
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| 4. |
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| 5. |
- Ekberg, Anders, 1967, et al.
(författare)
-
Guest editorial
- 2005
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Ingår i: Wear. ; 258:7-8, s. 953-954
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Tidskriftsartikel (refereegranskat)
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| 6. |
- Ekberg, Anders, 1967, et al.
(författare)
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Identifying the root causes of damage on the wheels of heavy haul locomotives and its mitigation
- 2014
-
Ingår i: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit. - : SAGE Publications. - 0954-4097 .- 2041-3017. ; 228:6, s. 663-672
-
Tidskriftsartikel (refereegranskat)abstract
- The paper illustrates how damage patterns in the form of rolling contact fatigue (RCF) on wheels, can be employed to identify and improve underlying operational conditions. The focus is on RCF of locomotive wheels operating on the Iron Ore Line in northern Sweden and Norway. Seasonal changes and damage patterns are charted. Potential root causes for observed damage patterns are identified and investigated. Mitigating actions are proposed and the efficiency of implemented actions is quantified.
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| 7. |
- Ekberg, Anders, 1967, et al.
(författare)
-
Identifying the root causes of damage on the wheels of heavy haul wheel damage phenomena
- 2013
-
Ingår i: Proceedings of the 10th International Heavy Haul Conference (IHHA 2013), February 4–6, New Dehli, India. ; , s. 520-526
-
Konferensbidrag (refereegranskat)abstract
- The paper illustrates how damage patterns, in particular in the form of rolling contact fatigue (RCF), can be employed to identify underlying operational conditions. In particular the focus is on RCF of wheel occurring at the Iron Ore line in north Sweden and Norway. The paper charts seasonal changes and damage patterns, and potential root causes are identified and investigated. Finally mitigating actions are proposed.
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| 8. |
- Ekberg, Anders, 1967, et al.
(författare)
-
RAIL AND WHEEL HEALTH MANAGEMENT
- 2022
-
Ingår i: CM 2022 - 12th International Conference on Contact Mechanics and Wear of Rail/Wheel Systems, Conference Proceedings. ; , s. 179-188
-
Konferensbidrag (refereegranskat)abstract
- Rail and wheel health management is investigated with focus on deterioration phenomena in the wheel/rail contact interface – plastic deformation, wear, and rolling contact fatigue (RCF). How operational conditions affect deterioration, and how they can be included in track health predictions is discussed together with a more in-depth description of deterioration mechanisms. Here means of measuring, quantifying, and predicting deterioration is in focus. This provides the basis for the outline of a rail and wheel health management framework. As discussed in the paper, the proposed framework is well in line with the requirements in the ISO 55000 standard for asset management.
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| 9. |
- Ekberg, Anders, 1967, et al.
(författare)
-
Rail and wheel health management
- 2023
-
Ingår i: Wear. - 0043-1648. ; 526-527
-
Tidskriftsartikel (refereegranskat)abstract
- Rail and wheel health management is investigated with focus on deterioration phenomena in the wheel/rail contact interface – plastic deformation, wear, and rolling contact fatigue (RCF). How operational conditions affect deterioration, and how they can be included in wheel/rail health predictions is linked to a more in-depth description of deterioration mechanisms. Here means of measuring, quantifying, and predicting deterioration is in focus. This discussion provides the basis for the outline of a rail and wheel health management framework. As discussed in the paper, the proposed framework is well in line with the requirements in the ISO 55000 standard for asset management.
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| 10. |
- Ekberg, Anders, 1967, et al.
(författare)
-
Stress gradient effects in surface initiated rolling contact fatigue of rails and wheels
- 2016
-
Ingår i: Wear. - : Elsevier BV. - 0043-1648. ; 366-367, s. 188-193
-
Tidskriftsartikel (refereegranskat)abstract
- The paper investigates gradient effects, which relate to how highly stressed regions should be dealt with in fatigue design analyses. In particular stress gradients in rolling contact are investigated with a focus on differences in response between full and partial slip conditions. To this end the multiaxial state of stress beneath a wheel–rail contact featuring full or partial slip is quantified using a multiaxial equivalent stress criterion. A comparative study shows that the significant differences in peak interfacial shear stress magnitudes between full and partial slip conditions are significantly reduced when translated to equivalent stress magnitudes. An innovative procedure to quantify the gradient effects by comparing the multiaxial contact stress field to uniaxial conditions is developed and employed. For the studied cases stress gradients beneath the frictional contact were found to be similar to stress gradients outside a uniaxially loaded large plate featuring a small hole with a radius in the order of 0.5–0.7 mm. The study concludes that the use of local magnitudes of interfacial shear stress in the analysis of surface initiated rolling contact fatigue under partial slip conditions is conservative. The analysis framework established in the current study can be used to estimate the level of conservativeness.
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| 11. |
- Ekberg, Anders, 1967, et al.
(författare)
-
Stress gradient effects in surface initiated rolling contact fatigue of rails and wheels
- 2015
-
Ingår i: Proceedings of the 10th International Conference on Contact Mechanics and Wear of Rail/Wheel Systems (CM2015).
-
Konferensbidrag (refereegranskat)abstract
- The paper investigates gradient effects, which relates to how highly stressed regions should be dealt with in fatigue design analyses. In particular stress gradients in rolling contact are investigated with a focus on differences in response between full or partial slip conditions. To this end the multiaxial state of stress beneath a wheel–rail contact featuring full or partial slip is quantified using a mulitaxial equivalent stress criterion. A comparative study shows that the significant differences in peak interfacial shear stress magnitudes between full and partial slip conditions are significantly reduced when translated to equivalent stress magnitudes. In addition, stress gradients beneath a frictional contact are compared to stress gradients outside a uniaxially loaded small hole in a plate and was found to correspond to hole radii in the order of 0.5– 0.7 millimetres for the cases studied. The study concludes that the use of local magnitudes of interfacial shear stress in the analysis of surface initiated rolling contact fatigue is conservative. The analysis framework established in the current study can be used to estimate the level of conservativeness.
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| 12. |
|
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| 13. |
- Esmaeili, Ali, 1983, et al.
(författare)
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Thermomechanical cracking of railway wheel treads: a combined experimental and numerical approach
- 2015
-
Ingår i: Proceedings of the 10th International Conference on Contact Mechanics and Wear of Rail/Wheel Systems (CM2015). ; , s. 8-
-
Konferensbidrag (refereegranskat)abstract
- In the present study, thermal cracking of railway wheel treads is studied by full-scale brake rig tests and finite element simulations. The focus is on thermomechanical rolling contact fatigue (RCF) life predictions. The wheel tread material is subjected to simultaneous mechanical and thermal loads due to rolling contact and stop braking, respectively. Full-scale tests featuring three series of repeated stop braking cases have been performed at the Railway Technical Research Institute (RTRI) in Japan in a brake rig featuring a tread braked wheel that is in rolling contact with a railwheel. The brake rig test conditions have been simulated numerically using the finite element method. To this end, the effect of “hot bands” on the tread is accounted for as indicated by the experimental findings. Thermomechanical stresses induced by braking as well as Hertzian contact loading on the tread including tractive loads based on a partial slip assumption are considered. The mechanical response of the wheel material ER7 is obtained from a viscoplastic Chaboche material model calibrated against data from cyclic experiments with hold-time from room temperatures up to 650 °C. Finally, a strategy for prediction of fatigue life with respect to ratcheting failure is discussed.
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| 14. |
- Fröhling, Robert, et al.
(författare)
-
Guest editorial of Special Issue on High Tech in Heavy Haul
- 2009
-
Ingår i: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit. - : SAGE Publications. - 0954-4097 .- 2041-3017. ; 223, s. i-ii
-
Tidskriftsartikel (refereegranskat)
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| 15. |
- Fröhling, Robert, et al.
(författare)
-
Preface: Special issue on heavy haul
- 2019
-
Ingår i: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit. - : SAGE Publications. - 0954-4097 .- 2041-3017. ; 233:6, s. 595-595
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 16. |
- Gullers, Per, et al.
(författare)
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High-frequency vertical wheel-rail contact forces – field measurements and influence of track irregularities
- 2008
-
Ingår i: Wear. - 0043-1648. ; 265:9-10, s. 1472-1478
-
Tidskriftsartikel (refereegranskat)abstract
- Field measurements of vertical wheel–rail contact forces in the frequency range 0–2000 Hz are reported. Instrumented wheels are employed together with a new method for signal processing including suppression of disturbing wheel resonances. Four different classes of rail irregularities are identified which all require consideration of high-frequency dynamics when evaluating wheel–rail contact forces. Ten stretches of Swedish track were selected for inspection and measurement of rail irregularities. The expected correlation between rail corrugation and measured dynamic forces is confirmed. It is found that high-frequency dynamics in the range 100–1250 Hz contributes significantly to contact forces which are important in the development of rolling contact fatigue. The present application is to high-speed trains on the Swedish track network with its mixed passenger and freight traffic. However, the method makes it possible to assess the level of high-frequency wheel–rail contact forces for all types of train traffic and could be used for a quantitative analysis of a complete railway network.
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| 17. |
- Ikeuchi, K., et al.
(författare)
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Wheel tread profile evolution for combined block braking and wheel-rail contact - Results from dynamometer experiments
- 2015
-
Ingår i: 10th International Conference on Contact Mechanics of Wheel / Rail Systems, CM 2015, Colorado Springs, United States, 30 August - 3 September 2015.
-
Konferensbidrag (refereegranskat)abstract
- Wheel treads are subject to different types of damage such as wear, rolling contact fatigue (RCF), thermal cracks, plastic deformation and also flats caused by wheel sliding. Some of these phenomena is followed by a change in tread profile which results in frequent wheel reprofiling to keep rich comfort of the vehicle. In this study, a series of full-scale tread braking experiments, including wheel-rail rolling contact, were conducted in order to clarify the influencing factors of evolution of wheel tread profile. The experiments focused on plastic deformation and wear caused by rolling contact and tread braking. The presented results show that the maximum tread depression is 0.20 mm at the rolling contact center after 40 times stop braking actions. This is considered to be caused by plastic deformation of the wheel tread induced by high contact pressure and material softening due to high temperatures from tread braking. This result is supported by the observed protrusion of the tread near the rolling contact area and also by a difference of hardness between the rolling contact area and other tread area.
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| 18. |
- Ikeuchi, K., et al.
(författare)
-
Wheel tread profile evolution for combined block braking and wheel–rail contact: Results from dynamometer experiments
- 2016
-
Ingår i: Wear. - : Elsevier BV. - 0043-1648. ; 366-367:SI, s. 310-315
-
Tidskriftsartikel (refereegranskat)abstract
- Wheel treads are subject to different types of damage such as wear, rolling contact fatigue (RCF), thermal cracks, plastic deformation and flats caused by wheel sliding. These types of damage cause changes in the tread profile of the wheel, which necessitates frequent wheel reprofiling in order to maintain the ride comfort of the vehicle. In this study, a series of full-scale tread braking experiments, including wheel–rail rolling contact, were conducted to clarify the factors influencing the wheel tread profile evolution. The experiments focused on plastic deformation and the wear caused by the rolling contact and tread braking. The results showed that the maximum tread indentation was 0.20 mm at the rolling contact center when the stop braking action was repeated 40 times. This was caused by the plastic deformation of the wheel tread, which, in turn, was the result of high contact pressure and material softening from high temperatures caused by tread braking. The results were supported by the observed tread protrusions near the rolling contact area and also by the difference in the rolling contact area hardness and that of the other wheel tread areas.
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| 19. |
|
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| 20. |
|
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| 21. |
- Landström Voortman, Eric, 1993, et al.
(författare)
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Analysis and testing of tread braked railway wheel — Effects of hot spots on wheel performance
- 2024
-
Ingår i: International Journal of Fatigue. - 0142-1123. ; 180
-
Tidskriftsartikel (refereegranskat)abstract
- To investigate the impact of localised heating phenomena in the form of hot spots on wheel performance in general and on wheel residual stress state in particular, a combination of experimental testing and finite element simulations of tread braked wheels has been performed. Using a newly established full-scale railway brake test rig, a wheel is exposed to prolonged drag braking applications at constant power levels to induce high temperatures on the wheel tread. The distribution and evolution of the temperature is studied using a high-speed, high-resolution thermographic camera in addition to traditional sliding thermocouples. Measured temperature data are then used in combination with a thermomechanically calibrated material model to simulate the wheel behaviour. For this purpose, a 3D finite element model representing a sector of a railway wheel is used. The experimental results show that the temperatures measured utilising sliding thermocouples provide insufficient information since they cannot resolve the uneven tread temperatures given typical response times. Non-uniform heating is found to have a significant effect on tensile residual stresses in the rim. Especially the case with global uneven temperatures is found to generate potentially hazardous residual stresses. The results presents future challenges for the analysis and development of the brake-wheel-rail system.
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| 22. |
- Landström Voortman, Eric, 1993, et al.
(författare)
-
Improved Finite Element Modelling of Tread Braked Wheel Performance Verified by Brake Rig Tests
- 2023
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The objective of the present study is to validate a finite element material model for railway wheel steel against brake rig test results. The material model for pearlitic ER7 wheel steel has been calibrated for thermomechanical loading based upon the regulatory requirements for brake rig tests using specimen test results. The material model has shown better adherence to thermomechanical results compared to previous material models, but ultimately full-scale validation is required. To verify and further develop the model, a combined experimental and numerical campaign was launched. Using a custom-built brake rig at Chalmers University, two different designs of European freight wheels are tested at power levels of 30 and 50 kW for durations of up to 45 min with maximum temperatures exceeding 600 °C. Wheel rim displacements are measured during experiments and residual stresses are measured before and after each test using an instrument employing the elastoacoustic effect. Temperatures are measured using thermocouples on the wheel web, sliding thermocouples on the tread and a high-speed thermographic camera. The experimental results are then compared to finite element simulations at the same brake power levels using the aforementioned material model. The results show possible correspondence between the experimental and finite element results, indicating that the numerical model may be accurate enough for preliminary predictions of braking damage, while also highlighting challenges of thermal model assumptions.
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| 23. |
- Landström Voortman, Eric, 1993, et al.
(författare)
-
Improved modelling of tread braked wheels using an advanced material model
- 2022
-
Ingår i: FISITA Library. ; EB2022:RLB
-
Konferensbidrag (refereegranskat)abstract
- The objective of the present study is to investigate and examine the capabilities of a novel material model, calibrated using anisothermal experimental data, when employed in detailed braking simulations corresponding to brake test rig conditions. To achieve this, an axisymmetric finite element model of a standard freight wheel exposed to tread braking is used to assess the performance of the material model. The finite element model accounts, in a simplified fashion, for residual stresses introduced by the rim hardening process at wheel manufacturing and also for variations in material properties based on typical hardness values on a wheel cross section. A range of braking situations are assessed to achieve different loads and temperatures, by mimicking downhill braking at constant speed for a prolonged time period. The results are compared between the new anisothermally calibrated model, two other similar material models previously developed for wheel simulations that are calibrated merely by isothermal data as well as a simpler model used in industry. Additionally, some comparisons are also made with the pertinent European standard on technical approval for forged wheels. The results show that the new calibrated material model predicts realistic material behaviour for a wide range of braking situations. Compared with previous models, conservative predictions are found with higher residual tensile stresses after braking and also larger residual displacements, as well as larger areas with plastic strains. The study also highlights the importance of knowing the spatial distribution of the residual stresses when comparing average residual stresses in the wheel rim. The new features of the material model contribute substantially to more accurate modelling of the processes occurring in the wheel during high temperature tread braking, although at the cost of prolonged duration of the numerical analyses.
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| 24. |
- le Gigan, Gael, 1985, et al.
(författare)
-
Disc brakes for heavy vehicles: An experimental study of temperatures and cracks
- 2015
-
Ingår i: Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering. - : SAGE Publications. - 2041-2991 .- 0954-4070. ; 229:6, s. 684-707
-
Tidskriftsartikel (refereegranskat)abstract
- A better understanding of the thermomechanical loading of brake discs is important for controlling material fatigue and crack propagation in the disc. In the present study, full-scale drag braking experiments were performed on brake discs made from eight different grey cast iron alloys. The well-performing materials were also tested with an alternative brake pad material. A testing procedure with repeated drag brakings was used. The disc and pad temperatures were registered by thermocouples embedded at selected locations, and the disc surface temperatures by a thermocamera. Extensive analyses of the measured temperatures were performed. The results for the thermocouples at the mid-radius of the disc and at the end of brake applications indicatd that the two sides of the disc have opposite deviations from the mean temperature. The temperature deviations are generally temporally alternating, but also stationary variations can be found. The thermocamera gives the possibility of identifying the phenomena behind the temperature variations found from the thermocouples. Banding of the disc–pads contact with alternating one band and two bands of high temperatures is observed for the studied brake discs exposed to severe braking load cases. Moreover, it was found that hot-spot patterns develop on the disc surface, which are spatially fixed during each brake application. However, they may be either slowly migrating or fixed relative to the disc during consecutive brake applications. Thermal images show that small cracks do not affect hot-spot migration as a hot spot migrates over the crack. However, at a critical length of the crack, the heat becomes localized at the crack and increases its growth, thus limiting the life of the disc. The tests indicate that a combination of hot-spot migration, alternating bands and small temperature differences over the disc are significant factors to be considered when improving the lifespan of the discs.
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| 25. |
- le Gigan, Gael, 1985, et al.
(författare)
-
Modelling of grey cast iron for application to brake discs for heavy vehicles
- 2017
-
Ingår i: Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering. - : SAGE Publications. - 2041-2991 .- 0954-4070. ; 231:1, s. 35-49
-
Tidskriftsartikel (refereegranskat)abstract
- Cast iron brake discs are commonly used in the automotive industry, and efforts are being made to gain a better understanding of the thermal and mechanical phenomena occurring at braking. The high thermomechanical loading at braking arises from interaction between the brake disc and the brake pads. Frictional heating generates elevated temperatures with a non-uniform spatial distribution often in the form of banding or hot spotting. These phenomena contribute to material fatigue and wear and possibly also to cracking. The use of advanced calibrated material models is one important step towards a reliable analysis of the mechanical behaviour and the life of brake discs. In the present study, a material model of the Gurson-Tvergaard-Needleman type is adopted, which accounts for asymmetric yielding in tension and compression, kinematic hardening effects, viscoplastic response and temperature dependence. The material model is calibrated using specimens tested in uniaxial cyclic loading for six different temperatures ranging from room temperature to 650 °C. A special testing protocol is followed which is intended to activate the different features of the material model. Validation of the model is performed by using tensile tests and thermomechanical experiments. An application example is given where a 10° sector of a brake disc is analysed using the commercial finitie element code Abaqus under a uniformly applied heat flux on the two friction surfaces. The results indicate that the friction surface of the hat side and the neck can be critical areas with respect to fatigue for the uniform heating studied.
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| 26. |
- le Gigan, Gael, 1985, et al.
(författare)
-
Thermomechanical fatigue of brake disc materials--results from modelling and experiments
- 2012
-
Ingår i: Proceedings EuroBrake 2012. ; , s. EB2012-MS-31-
-
Konferensbidrag (refereegranskat)abstract
- The loads and the material response of a brake disc in the actual braking situation are complicated to analyse. In order to study thermomechanical fatigue, test specimens having controlled boundary conditions are regularly employed. In the present paper, results from analytical modelling, finite element modelling and experiments are analysed and compared for a constrained TMF test. Standard rheological material models, adapted to account for the tension-compression asymmetry with respect to yield for the studied gray cast iron, are used to study investigate the specific TMF test set-up. It is found that the stress evolution during testing can be well described using the studied models. Assessment of fatigue laws from the literature gives mixed results, highlighting the importance of finding damage parameters for the actual studied material.
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| 27. |
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| 28. |
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| 29. |
- Lundén, Roger, 1949
(författare)
-
Elastoplastic modelling of subsurface crack growth in rail/wheel contact problems
- 2007
-
Ingår i: Fatigue & Fracture of Engineering Materials and Structures. ; 30:10, s. 889-991
-
Tidskriftsartikel (refereegranskat)abstract
- Propagation of small subsurface cracks subjected to shear under repeated rolling contact load is studied. An analytical crack model (Dugdale) with plastic strips at the two crack tips is employed. Compressive stresses promoting crack closure and friction between crack faces are considered. The triaxial stress state is used in the yield criterion. A damage criterion is suggested based on experimental LCF data. In a numerical study, critical crack lengths are found below which propagation of an existing crack should be effectively suppressed.
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| 30. |
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| 31. |
- Lundén, Roger, 1949, et al.
(författare)
-
Introduction to wheel-rail interface research
- 2009
-
Ingår i: Wheel/Rail Interface Handbook (editors R Lewis and U Olofsson), Woodhead Publishing, Cambridge (UK). ; , s. 3-33
-
Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- History and present situation. Phenomena in the wheel-rail interface. Research fields. Applications. Ongoing research, development and standardization efforts. System aspects and optimization. Future trends. Sources of further information and advice. Acknowledgements. References.
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| 32. |
- Lundén, Roger, 1949, et al.
(författare)
-
New wheels for 25 and 30 tonne axle loads – design, stresses and geometric stability
- 2004
-
Ingår i: Proceedings 6th International Conference on Railway Bogies and Running Gears (Bogie ‘04). ; , s. 265-270
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Two freight wheels for 25 and 30 tonne axle loads have been designed. Requirements on the wheels from European point of view, according to CEN and UIC, are discussed along with particular (more strict) requirements on wheels in Sweden, according to SJ. Good performance of the wheels under high thermal loads at gradient braking is at focus. The shrink fitting method is discussed together with the magnetic induction heating method that only heats the hub of the wheel, which is used in Sweden for mounting the wheels onto the axles.
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| 33. |
- Lundén, Roger, 1949, et al.
(författare)
-
New wheelsets for 25 and 30 tonne axle loads
- 2003
-
Ingår i: Internationale Schienenfahrzeugtagung (RAD Schiene 2003). ; , s. 6-
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Increased load capacity of wagons is a key factor for strengthening the economic viability of railway freight transportation and thus an important step towards increasing the railway’s share of goods. Consequently, there is a demand for wheels and axles that can sustain higher axle loads.In co-operation with Chalmers University of Technology, the development of new wheels and axles for 25 and 30 tonne axle loads started at Lucchini Sweden several years ago. This was part of a project initiated by the demand for wheelsets carrying higher axle loads on the Iron Ore Line in northern Sweden and Norway. The primary aim was to achieve good performance of the wheels under high thermal loads at gradient braking. Focus has been on reduction of change of wheel gauge during and after braking and on keeping the residual tensile stresses induced in the wheel rim by the braking at a low level. The wheels are forged and rolled and the material R7 is used. The axles are designed according to EN 13103 and the material A1N is used. The axles are not further discussed in this paper.
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| 34. |
- Lundén, Roger, 1949, et al.
(författare)
-
Railway axle design – to be based on fatigue initiation or crack propagation?
- 2010
-
Ingår i: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit. - 0954-4097 .- 2041-3017. ; 224:5, s. 445-453
-
Tidskriftsartikel (refereegranskat)abstract
- Design and standardization of railway axles from the mechanical-strength point of view is discussed and a brief state-of-the-art survey is given. Traditional fatigue design with the ‘safe-life’ approach and a design with the more recent crack-propagation/defect-tolerance approach are described and compared. Axles of a standard freight wheelset (22.5 tonne axle load) and of two heavy haul wheelsets (25 and 31 tonne axle loads) are used for illustration. From the numerical results it is concluded that a crack-propagation/defect-tolerance approach could be a useful complement to the traditional fatigue design method. A result of particular interest is the fairly strong influence of stresses from the press-/shrink-fitting on the residual life of the axles.
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| 35. |
- Lundén, Roger, 1949, et al.
(författare)
-
Railway axle design – to be based on fatigue initiation or crack propagation?
- 2009
-
Ingår i: Proceedings of the 9th International Heavy Haul Conference. ; , s. 509-517
-
Konferensbidrag (refereegranskat)abstract
- A numerical study is presented where the impact of simultaneous thermal and mechanical loading on a railway wheel tread as imposed by braking and rolling contact is reported. A comparison is made of 2D and 3D finite element simulations of the thermomechanical problem featuring a material model that accounts for thermal expansion and plastic deformations. It is found that 2D simulations give unrealistic predictions of plastic deformations. The 3D simulations demonstrate a significant influence of the thermal loading on the induced tensile stresses also in cases of rather moderate temperature increases.
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| 36. |
- Lundén, Roger, 1949, et al.
(författare)
-
The influence of corrugation on frictional stress at the rail-wheel interface
- 2016
-
Ingår i: Civil-Comp Proceedings. - 1759-3433. ; 110
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Tidskriftsartikel (refereegranskat)abstract
- The influence of rail and wheel corrugation on vertical and tractive forces is studied, in this paper, for high-speed trains with the aim of evaluating the risk for surface initiated rolling contact fatigue (RCF). A train-track interaction model for vertical dynamics, which accounts for a prescribed torque on the wheelset and for the highfrequency content of the induced force spectrum, is employed. Corrugation distributions according to ISO 3095 (smooth rail) and as obtained from field measurements (corrugated rail) are considered. A parametric study is carried out in which level of corrugation, tractive effort and vehicle speed are varied. Also the influences of axle load and unsprung mass are investigated. The results are interpreted in terms of rolling contact fatigue impact spectra and by using the Tgamma energy model. If is found that the two models give similar tendencies regarding the surface initiated RCF impact. As expected, the traction effort will dominate the development of RCF, but significant influences are also found for corrugation, speed, axle load and unsprung mass.
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| 37. |
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| 38. |
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| 39. |
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| 40. |
- Sandström, Johan, 1978, et al.
(författare)
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Deterioration of insulated rail joints – a three-year field study
- 2012
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Ingår i: Proceedings of the 9th International Conference on Contact Mechanics and Wear of Rail/Wheel Systems (CM2012). ; , s. 301-308
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Konferensbidrag (refereegranskat)abstract
- Four operational joints at the Swedish West Coast Line have been monitored in field from installation and during three years of operation to follow degradation. Even though operational loads were comparatively low, material damage was found to occur early after installation. All joints showed a similar damage pattern with dominating deformation on the side towards a nearby station. In addition some joints showed “cavity-like” damage on the off-station side. The paper reports observations on continuing degradation of the joints as well as hardness evolution and increased joint dip over time.
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| 41. |
- Singh Walia, Mandeep, 1987, et al.
(författare)
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Temperatures and wear at railway tread braking: Field experiments and simulations
- 2019
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Ingår i: Wear. - : Elsevier BV. - 0043-1648. ; 440-441
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Tidskriftsartikel (refereegranskat)abstract
- Field tests were carried out for a commuter train in revenue service equipped with cast iron and organic composite brake blocks. Temperatures for wheel tread, wheel web and brake blocks and wear of wheel treads and brake blocks were recorded. The measured temperatures are used for calibrating a thermal model for assessment of wheel and block temperatures. The wear of cast iron and organic composite brake blocks is estimated using simulated temperatures and temperature-dependent wear models based on pin-on-disc experiments. It is found that a wear rate adaption factor, tentatively motivated by the presence of thermoelastic instabilities at full-scale braking that cannot be found at small-scale testing, is required for producing a simulated wear that is in agreement with results from field tests. Wheel tread wear is assessed as change in flange height for both powered and trailing wheels and for the studied train it is found that the levels of annual total wear of these types of wheels are similar in magnitude. Modelling of the tread wear originating from block–wheel contact and wheel−rail contact, combined with a comparison with measured wear magnitudes, makes it possible to quantify the wear from these two tread contacts. It is found for the powered wheels that wear induced by the wheel-rail contact and the block-wheel contact have equal importance, whereas for the trailer wheels the wear emanating from the block-wheel contact is dominating.
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| 42. |
- Teimourimanesh, Shahab, 1982, et al.
(författare)
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Modelling of temperatures during railway tread braking: Influence of contact conditions and rail cooling effect
- 2014
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Ingår i: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit. - : SAGE Publications. - 0954-4097 .- 2041-3017. ; 228:1, s. 93-109
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Tidskriftsartikel (refereegranskat)abstract
- The temperature rise of wheels and blocks due to frictional heating during railway tread braking along with the transfer of heat through the wheel–rail contact is studied in this paper. In particular, heat partitioning between block, wheel and rail for stop braking cycles is considered. The wheels are of interest because they are a limiting factor for railway tread braking systems. Two types of thermal models are employed to investigate the maximum temperatures over the wheel tread. In a circumferential (plane) model of wheel, block and rail, the heat transfer problem is studied by use of a finite element formulation of the two-dimensional time-dependent convection–diffusion equation. The hot spot phenomenon is simulated by introducing a prescribed wheel-fixed contact pressure distribution between wheel and block. In an axisymmetric (axial) model of wheel, block and rail, the lateral movements of the wheel–rail contact are studied. A general result is that the cooling effect provided by the rail is important when local temperatures on the tread are considered, but not when studying bulk temperatures created in a single stop braking event. Furthermore, it is found from the lateral movements of the wheel–rail contact that slow oscillations result in maximum temperatures over the wheel tread that are somewhat lower than for travelling on straight track (rolling at the rolling circle).
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| 43. |
- Teimourimanesh, Shahab, 1982, et al.
(författare)
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Thermal capacity of tread-braked railway wheels. Part 1: Modelling
- 2016
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Ingår i: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit. - : SAGE Publications. - 0954-4097 .- 2041-3017. ; 230:3, s. 784-797
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Tidskriftsartikel (refereegranskat)abstract
- Tread brakes are still a common frictional braking system used on metro and suburban trains. Here the wheels are safety-related components and there is a need to develop design specifications and guidelines to ensure that the wheels perform properly under the service conditions to which they are exposed. In the present paper, a model is proposed and developed that represents typical conditions in metro and suburban operations, in particular during sequential stop braking. The analysis also considers drag braking, mechanical loading, residual stresses and wheel-axle interference fit. Finite element modelling, with an advanced temperature-dependent material model, together with a fatigue analysis is employed to quantify the wheel's performance. An application example demonstrates the method for a typical metro wheel. In a companion paper, further applications are presented that demonstrate important aspects of the thermal capacity of tread-braked railway wheels.
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| 44. |
- Teimourimanesh, Shahab, 1982, et al.
(författare)
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Thermal capacity of tread-braked railway wheels. Part 2: Applications
- 2016
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Ingår i: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit. - : SAGE Publications. - 0954-4097 .- 2041-3017. ; 230:3, s. 798-812
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Tidskriftsartikel (refereegranskat)abstract
- Tread braking is a common friction-based braking system that finds use on metro and suburban trains. Here the wheels are safety-related components and there is a need to develop design specifications and guidelines to ensure that the wheels perform properly under the service conditions to which they are exposed. In the present paper, examples of applications are given that employ a modelling framework that was developed in a companion paper. The examples represent typical conditions in metro and suburban operations, in particular during sequential stop braking. Also results for drag braking, mechanical loading, residual stresses and wheel-axle interference fit are given. Parametric studies are performed to demonstrate the influence of load levels and other factors on the fatigue life of the wheels. The results should be useful for establishing design rules that consider the thermal capacity of tread-braked railway wheels.
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| 45. |
- Teimourimanesh, Shahab, 1982, et al.
(författare)
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Tread braking of railway wheels ─ state-of-the-art survey
- 2010
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Ingår i: Proceedings 6th European Conference on Braking (JEF2010 / 6ème Conférence Européenne du Freinage), Lille (France) 24-25 November 2010. ; , s. 293-302, s. 18 pp.-
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Konferensbidrag (refereegranskat)abstract
- An overview of design methods for tread braking systems is given with special focus on the braking capacity of the wheels. Several aspects of the tread braking system, important for the dimensioning of railway wheels, are assessed, such as brake block materials, residual stresses and temperature gradients through wheel rim and wheel disc. The influence of heat partitioning between wheel, brake block and rail on wheel temperatures for different braking cycles is considered. Two examples with numerical results on thermomechanical behaviour of tread braking systems are given regarding the freight and metro applications.
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| 46. |
- Teimourimanesh, Shahab, 1982, et al.
(författare)
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Tread braking of railway wheels – temperatures generated by a metro train
- 2014
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Ingår i: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit. - : SAGE Publications. - 0954-4097 .- 2041-3017. ; 228:2, s. 210-221
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Tidskriftsartikel (refereegranskat)abstract
- Tread braking of railway wheels results in the kinetic energy of the train being dissipated into the wheel and blocks in the form of heat. This heat is further conducted into adjacent structures, notably the cold rail, and also transferred into the surroundings by convection and radiation. Heat partitioning between wheel and block is, for short time periods, controlled by local thermal interactions at the contact point and by the conductive properties of the bodies. However, for a metro train that performs longer periods of intermittent braking (or for drag braking) convective and radiation cooling properties of the components come into play. In the present study, results from brake rig tests and from in-field testing of a metro train are presented and used to calibrate a simulation model. It is found that the cooling level of the wheels of the metro train is substantially lower than for the wheels of a freight wagon. Moreover, it is found that the first axle on the metro train is exposed to higher cooling levels than the remaining axles. In a numerical example, temperatures of tread braked wheels are calculated using the new findings for a metro train, and the results obtained are compared with wheel temperatures as calculated assuming freight wagon conditions.
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| 47. |
- Vernersson, Tore V, 1968, et al.
(författare)
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Temperatures at railway tread braking – A parametric study
- 2007
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Ingår i: Proceedings 15th International Wheelset Congress (IWC15), Prague, Czech Republic, 23-27 September 2007, 16 pp (available on CD).
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Konferensbidrag (refereegranskat)abstract
- A thermal model of railway tread braking has previously been developed for use in calculations of wheel and brake block temperatures. Block(s) and wheel are coupled via a contact interface that controls the heat generation and also the heat partitioning between block and wheel. Heat transfer from the rolling wheel into the rail is accounted for. The thermal model was calibrated using results from both standard brake rig tests and tests when a “rail-wheel” was introduced in the rig. Furthermore, the model was successfully calibrated using results from field studies.In the present work, the thermal model is utilised to study temperatures and partitioning of heating power during different braking set-ups and braking loads. First, the influences from geometrical changes are studied, with parameters such as wheel design, wheel wear and block wear. Also the effect of brake block configuration is studied. Second, the influence from brake block material is considered. Third, the influences from braking parameters are studied. Gradient braking on mountain descents is simulated but also the related case of brake system malfunctioning. Stop braking is studied. Fourth, the importance of rail chill is investigated with respect to shape and size of the contact patch between wheel and rail. A general result from the present parametric study is that rail chill is important for a useful simulation of wheel temperatures and heat partitioning at drag braking. Rail chill consumes a considerable part of the total heat at drag braking and it becomes increasingly important as the tread temperature rises. For example, at the end of a brake cycle at 30 kW per wheel for 30 min with composition brake blocks using a 920 mm wheel, 21 % of the total heat enters the rail.
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| 48. |
- Vernersson, Tore V, 1968, et al.
(författare)
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Temperatures at railway tread braking. Part 3: wheel and block temperatures and the influence of rail chill
- 2007
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Ingår i: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit. ; 221:4, s. 443-454
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Tidskriftsartikel (refereegranskat)abstract
- Tread braking generates high temperatures in railway wheels and brake blocks as the kinetic energy of the running train is transformed into heat. The temperatures induced in the components are here analysed with particular focus on the cooling influence from the rolling contact between the hot wheel and a cold rail. Controlled brake rig tests are reported, where the rolling contact is studied using a so-called rail-wheel in contact with the braked wheel, along with results from field tests. The data from these experimental studies are used for calibration of a simulation tool for calculation of wheel and block temperatures. The calibrated model analyses heat partitioning between block, wheel and rail and finds the resulting temperatures at braking. The rail chill is found to have a considerable influence on the wheel temperatures for long drag braking cycles. A successful calibration of the model using data from field tests is also reported.
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| 49. |
- Vernersson, Tore V, 1968, et al.
(författare)
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Tread braking – fatigue life of railway wheel webs
- 2014
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Ingår i: Proceedings EuroBrake 2014 Conference. ; , s. 13 pp-
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Konferensbidrag (refereegranskat)abstract
- Tread braking is a common braking system for railway vehicles which is used mainly on freight wagons but also as a component on trains with mixed braking systems. In general, railway wheels for tread braking are designed only by considering a maximum allowed braking power according to the wheel design standard EN 13979-1. The idea is to avoid derailment risks due to change of wheelset gauge or global wheel fracture caused by excessive tensile stresses in the wheel rim. In the present paper, the fatigue life of the wheel web is studied in detail when subjected to a combination of thermomechanical loading from tread braking and mechanical loading from wheel-rail contact forces. Two generic wheel designs are assessed where one represents the classical freight wheel with a slightly S-shaped web and the other is a so-called low-stress wheel, with a more elaborate shape of the wheel web, specifically designed for high thermal loads. The wheel designs are studied both with new rims and with fully worn down rims. The results show that railway wheels generally have sufficient fatigue lives for regular service with respect to thermomechanical loading. Moreover, it is shown that the studied wheels have different sensitivities to mechanical and thermomechanical loadings at some critical positions on the wheel web. Towards the wheel rim, the damage as induced by tread braking is dominating and towards the hub the damage from mechanical loading is more important. A general conclusion is that maintenance of the wheel webs is important for preserving a high safety of the railway system.
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| 50. |
- Vernersson, Tore V, 1968, et al.
(författare)
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Tread braking of railway wheels – wheel and block temperatures and the influence of rail chill
- 2005
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Ingår i: Proceedings 8th International Heavy Haul Conference (IHHC8). ; , s. 253-260
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Tread braking generates high temperatures in railway wheels and brake blocks as the kinetic energy of the train is transformed into heat. The temperatures induced in the components are here analysed with particular focus on the cooling influence from the rolling contact between the hot wheel and a cold rail. Results from controlled brake rig tests are reported, where the rolling contact is studied using a so-called rail-wheel in contact with the braked wheel, along with results from field tests. The results from these experimental studies are used for calibration of a simulation tool for calculation of wheel and block temperatures. The calibrated model analyses heat partitioning between block, wheel and rail and to find the resulting temperatures at braking. It is found that the rail chill has a considerable influence on the wheel temperatures for long brake cycles. A successful calibration of the model for the field tests is also reported.
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