| 1. |
- Pålsson, Björn, 1981, et al.
(författare)
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Calibration of a model for dynamic vehicle – track interaction in crossing panels to comprehensive field measurements
- 2022
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- A so-called Whole System Model (WSM) for railway switches and crossings (S&C) is currently under development within the European research program Shift2Rail. The objective of the WSM is that it should allow for holistic simulation-based evaluation of S&C designs and ultimately provide input for Life Cycle Cost analysis and virtual homologation. At the centre of the WSM is a multibody simulation (MBS) model that evaluates the dynamic vehicle-track interaction for a given S&C design and traffic situation and generates wheel-rail contact quantities and structural responses for the following damage calculations. This paper is focused on the MBS model and present developments for a finite element track model of an S&C crossing panel. The developments concern the model itself and a calibration to measurement data from a comprehensively instrumented S&C demonstrator installed as a part of Shift2Rail activities in the Austrian railway network. The presented track model demonstrates an overall good agreement between measurements and simulation after minor and physical track parameter adjustments. A very good agreement is obtained at the center of the crossing panel at the crossing transition while discrepancies are found across the track along the sleeper that goes underneath the crossing transition. It is hypothesized that this discrepancy is due to variations in ballast stiffness distribution under the investigated sleeper. It is concluded that the presented track model can represent the track dynamics well enough to fulfil its function within the Whole System Modelling scheme.
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| 2. |
- Pålsson, Björn, 1981, et al.
(författare)
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Dynamic vehicle–track interaction and loading in a railway crossing panel–calibration of a structural track model to comprehensive field measurements
- 2024
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Ingår i: Vehicle System Dynamics. - 1744-5159 .- 0042-3114. ; In Press
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents a finite element model of a railway crossing panel for use in multibody simulations (MBS). It is a two-layer track model with rails and sleepers represented by beam elements that use linear bushings for rail fastenings and non-linear bushings for ballast. The model is calibrated and validated to measurement data from a comprehensively instrumented switch and crossing demonstrator installed in the Austrian railway network as a part of the European research programme Shift2Rail. The validation concerns the capability of the model to capture the structural response of the crossing panel under traffic loading after calibration of physical track parameters to realistic values. The structural response is measured in the form of displacements, strains, and sleeper-ballast contact forces. It is shown that the developed model can represent the measured track responses well and that it was necessary to account for a varying sleeper-ballast gap distribution along the crossing transition sleeper to obtain good agreement. The calibration uses Latin hypercube samples to explore the parameter space in a sensitivity analysis before a parameter optimisation is performed using a gradient-based method on a response surface built from a polyharmonic spline.
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| 3. |
- Sazgetdinov, K., et al.
(författare)
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A SEMI-PHYSICAL MODEL TO PREDICT PLASTICITY IN RAILWAY TURNOUT CROSSINGS
- 2022
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Ingår i: CM 2022 - 12th International Conference on Contact Mechanics and Wear of Rail/Wheel Systems, Conference Proceedings. ; , s. 749-754
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Konferensbidrag (refereegranskat)abstract
- Large dynamic contact forces in railway turnouts cause severe changes in the profile of the crossing-nose. To predict these changes, the whole system model (WSM) was developed, which uses extensive FEM simulations for the rail damage calculations that are very computationally intensive. To substitute these simulations and, thus, majorly enhance the overall performance of the WSM methodology, the semi-physical plasticity (SPP) metamodel has been developed. The SPP model is based on three foundational assumptions on the wear area, shape change area and wheel profiles envelope effects to reproduce the profile development of the crossing nose. The SPP results have shown an overall good correlation with the FEM results and, due to the semi-physical nature of the model, the computational time for such predictions was significantly improved as compared to the FEM simulations (seconds instead of weeks). The developed model will be useful for effective and time-efficient rail surface damage prediction and, as part of the WSM, contribute to the fast holistic track damage prognosis.
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| 4. |
- Skrypnyk, Rostyslav, 1991, et al.
(författare)
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Long-term rail profile damage in a railway crossing: Field measurements and numerical simulations
- 2021
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Ingår i: Wear. - : Elsevier BV. - 0043-1648. ; 472-473
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Tidskriftsartikel (refereegranskat)abstract
- Railway crossings are subjected to a severe load environment leading to a degradation of rail profiles due to wear and accumulated plastic deformation. This damage is the result of the high magnitudes of contact pressure and traction generated in the wheel–rail contact during each wheel transition between wing rail and crossing nose. An extensive measurement campaign has been carried out at a test site in Austria in a particularly severely loaded crossing manufactured from an explosion depth hardened (EDH) manganese steel grade. For an accumulated traffic load of 65 Mega-Gross-Tonnes (MGT), the evolution of profile degradation for 16 cross-sections along the crossing rail has been recorded on multiple occasions. The results from the measurement campaign are used to validate a previously presented multidisciplinary and iterative simulation methodology for the prediction of long-term rail damage. It is shown that the predicted rail profile degradation exceeds the measured degradation for some of the cross-sections but generally a good qualitative agreement is observed. Possible reasons for the higher predicted damage are the uncertain distribution of traffic at the test site and differences in material properties between the crossing in the field and the test specimens used for calibration of the cyclic plasticity model. The influence of the frequency of updating the rail profiles in the iterative simulation methodology, and the compromise between computational cost and the number of load cases accounted for in the applied load sequence, are addressed.
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| 5. |
- Vilhelmson, Henrik, 1997, et al.
(författare)
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Dynamic vehicle–track interaction and structural loading in a crossing panel–calibration and assessment of a model with a 3D representation of the crossing rail
- 2024
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Ingår i: Vehicle System Dynamics. - 1744-5159 .- 0042-3114. ; In Press
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Tidskriftsartikel (refereegranskat)abstract
- A three-dimensional (3D) finite element model of a railway crossing panel for use in multibody simulation (MBS) of dynamic vehicle–track interaction is presented. It is a two-layer track model with stock rails and sleepers represented by beam elements and a crossing rail represented by 3D solid elements. The track model uses linear bushings for the rail fastenings and bi-linear bushings for the ballast to allow for potentially voided sleepers. Based on the output from the MBS, the structural loading of the crossing in terms of strains, stresses and sleeper-ballast contact pressures is extracted in a post-processing step. The model is calibrated and validated to measurement data from a comprehensively instrumented switch & crossing (S&C) demonstrator installed in the Austrian railway network as a part of the European research programme Shift2Rail. The applied procedure for the calibration and critical assessment of the crossing model is described in detail. It is based on a model parameterisation with eight parameters relating to the rail fastening and foundation stiffnesses and to a distribution of the ballast voids. The calibration method uses Latin hypercube samples to explore the parameter space in a sensitivity analysis before a parameter optimisation is performed using a gradient-based method on a response surface built from a polyharmonic spline. In a comparative study it is shown that the 3D model and a more conventional beam model of the crossing rail show similar calibration results and good agreement with the measured data. The 3D model allows for the extraction of stress concentrations in the crossing rail but has an increased computational time of about 30% compared to the beam model.
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