| 1. |
- Ekberg, Anders, 1967, et al.
(författare)
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RAIL AND WHEEL HEALTH MANAGEMENT
- 2022
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Ingår i: CM 2022 - 12th International Conference on Contact Mechanics and Wear of Rail/Wheel Systems, Conference Proceedings. ; , s. 179-188
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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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| 2. |
- Ekberg, Anders, 1967, et al.
(författare)
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Rail and wheel health management
- 2023
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Ingår i: Wear. - 0043-1648. ; 526-527
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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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| 3. |
- 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
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Ingår i: International Journal of Fatigue. - 0142-1123. ; 180
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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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| 4. |
- Landström Voortman, Eric, 1993, et al.
(författare)
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Improved Finite Element Modelling of Tread Braked Wheel Performance Verified by Brake Rig Tests
- 2023
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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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| 5. |
- Landström Voortman, Eric, 1993, et al.
(författare)
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Improved modelling of tread braked wheels using an advanced material model
- 2022
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Ingår i: FISITA Library. ; EB2022:RLB
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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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