| 1. |
- Burgelman, Nico, et al.
(författare)
-
Influence of wheel-rail contact modelling on vehicle dynamic simulation
- 2015
-
Ingår i: Vehicle System Dynamics. - : Informa UK Limited. - 0042-3114 .- 1744-5159. ; 53:8, s. 1190-1203
-
Tidskriftsartikel (refereegranskat)abstract
- This paper presents a comparison of four models of rolling contact used for online contact force evaluation in rail vehicle dynamics. Until now only a few wheel-rail contact models have been used for online simulation in multibody software (MBS). Many more models exist and their behaviour has been studied offline, but a comparative study of the mutual influence between the calculation of the creep forces and the simulated vehicle dynamics seems to be missing. Such a comparison would help researchers with the assessment of accuracy and calculation time. The contact methods investigated in this paper are FASTSIM, Linder, Kik-Piotrowski and Stripes. They are compared through a coupling between an MBS for the vehicle simulation and Matlab for the contact models. This way the influence of the creep force calculation on the vehicle simulation is investigated. More specifically this study focuses on the influence of the contact model on the simulation of the hunting motion and on the curving behaviour.
|
|
| 2. |
- Casanueva, Carlos, 1981-, et al.
(författare)
-
Comparison of wear prediction models for different contact conditions
- 2016
-
Ingår i: Proceedings of the 24th Symposium of the International Association for Vehicle System Dynamics (IAVSD 2015), Graz, Austria, 17-21 August 2015. - : CRC Press. - 9781138028852 - 9781498777025 ; , s. 871-878
-
Konferensbidrag (refereegranskat)abstract
- Simulation of wheel and rail wear allows to predict long term profile evolution and thus, study the consequences of wheel damage in the dynamic behaviour of the vehicle, or study future maintenance requirements. Several models have been developed which try to solve the wear issue by relating the energy dissipated in the wheel-rail contact to the worn out material, from which two can be highlighted (Tg/A and Archard) which have significant differences on contact level. Even though, the prediction of long term wheel profile evolution has been validated with these two models, which means that for regular applications they seem to have an equivalent behaviour. In this work similarities and differences between the long term wear prediction methodologies are analysed, discussing their actual limitations. Then, these differences are exploited in specific operational cases to compare their wear prediction performance.
|
|
| 3. |
|
|
| 4. |
- Casanueva, Carlos, 1981-, et al.
(författare)
-
On integrated wheel and track damage prediction using vehicle-track dynamic simulations
- 2017
-
Ingår i: Proceedings of the Institution of mechanical engineers. Part F, journal of rail and rapid transit. - : Sage Publications. - 0954-4097 .- 2041-3017. ; 231:7, s. 775-785
-
Tidskriftsartikel (refereegranskat)abstract
- The renewal costs for wheels and rails are a substantial part of the costs for rolling stock operators and infrastructure managers all over the world. The causes for reprofiling or grinding are, in most cases, related to the following: (1) wheel or rail profiles with unacceptable wear, (2) appearance of rolling contact fatigue cracks in the surface, and (3) wheel flats caused by locking wheels during braking. The first two causes are related to the dynamic behavior of the vehicle-track system, and can be predicted using multibody simulations. However, there are several limitations that restrain the usefulness of these prediction techniques, such as simulation time constraints, necessary simplifications, and lack of experimental data that lead to educated assumptions. In this paper, we take the end-user perspective in order to show whether the latest developments in wheel-rail damage prediction can be integrated in a simplified framework, and subsequently used by the different stakeholders for an improved management of the different assets involved in the operation of rail vehicles.
|
|
| 5. |
- Dirks, Babette, et al.
(författare)
-
Prediction of wheel profile wear and crack growth : Comparisons with measurements
- 2015
-
Ingår i: CM 2015 - 10th International Conference on Contact Mechanics of Wheel / Rail Systems.
-
Konferensbidrag (refereegranskat)abstract
- A model which can predict the surface crack length and crack depth in rails was developed in a previous study by the authors1. In the present study, this crack prediction model in combination with a wear prediction model is verified against wheel measurements. For a period of 15 months, the wheels of three units of a Stockholm commuter train were measured with respect to wear and crack development. Vehicle-track dynamics simulations were used to calculate the forces and contact positions for the wear and crack prediction models. It can be concluded that the wear prediction model gives reasonable results, especially considering the large scatter in the wheel profile measurements. Although the crack prediction model had to be adjusted for the current wheel application, the results appear promising.
|
|
| 6. |
- Dirks, Babette, et al.
(författare)
-
Prediction of wheel profile wear and crack growth - comparisons with measurements
- 2016
-
Ingår i: Wear. - : Elsevier. - 0043-1648 .- 1873-2577. ; 366, s. 84-94
-
Tidskriftsartikel (refereegranskat)abstract
- A model which can predict the length of the surface crack and crack depth in rails was developed in a previous study by the authors B. Dirks, R. Enblom, A. Ekberg, M. Berg (2015) []. In the present study, verification of this crack prediction model in combination with a wear prediction model was done against wheel measurements. For a period of 15 months, the wheels of three units of a Stockholm commuter train were measured with respect to wear and crack development for verification of the wheel life prediction tool. Vehicle-track dynamics simulations were used to calculate the forces and contact positions for the wear and crack prediction models. It can be concluded that the wear prediction model gives reasonable results, especially considering the large scatter in the wheel profile measurements. Although the wheel life prediction tool could not be verified, since the crack prediction model had to be recalibrated for the current wheel application, the results appear promising.
|
|
| 7. |
- Dirks, Babette, 1976-
(författare)
-
Simulation and Measurement of Wheel on Rail Fatigue and Wear
- 2015
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The life of railway wheels and rails has been decreasing in recent years. This is mainly caused by more traffic and running at higher vehicle speed. A higher speed usually generates higher forces, unless compensated by improved track and vehicle designs, in the wheel-rail contact, resulting in more wear and rolling contact fatigue (RCF) damage to the wheels and rails. As recently as 15 years ago, RCF was not recognised as a serious problem. Nowadays it is a serious problem in many countries and ''artificial wear'' is being used to control the growth of cracks by preventive re-profiling and grinding of, respectively, the wheels and rails. This can be used because a competition exists between wear and surface initiated RCF: At a high wear rate, RCF does not have the opportunity to develop further. Initiated cracks are in this case worn off and will not be able to propagate deep beneath the surface of the rail or wheel.When wheel-rail damage in terms of wear and RCF can be predicted, measures can be taken to decrease it. For example, the combination of wheel and rail profiles, or the combination of vehicle and track, can be optimised to control the damage. Not only can this lead to lower maintenance costs, but also to a safer system since high potential risks can be detected in advance.This thesis describes the development of a wheel-rail life prediction tool with regard to both wear and surface-initiated RCF. The main goal of this PhD work was to develop such a tool where vehicle-track dynamics simulations are implemented. This way, many different wheel-rail contact conditions which a wheel or a rail will encounter in reality can be taken into account.The wear prediction part of the tool had already been successfully developed by others to be used in combination with multibody simulations. The crack prediction part, however, was more difficult to be used in combination with multibody simulations since crack propagation models are time-consuming. Therefore, more concessions had to be made in the crack propagation part of the tool, since time-consuming detailed modelling of the crack, for example in Finite Elements models, was not an option. The use of simple and fast, but less accurate, crack propagation models is the first step in the development of a wheel-rail life prediction model.Another goal of this work was to verify the wheel-rail prediction tool against measurements of profile and crack development. For this purpose, the wheel profiles of trains running on the Stockholm commuter network have been measured together with the crack development on these wheels. Three train units were selected and their wheels have been measured over a period of more than a year. The maximum running distance for these wheels was 230,000 km.A chosen fatigue model was calibrated against crack and wear measurements of rails to determine two unknown parameters. The verification of the prediction tool against the wheel measurements, however, showed that one of the calibrated parameters was not valid to predict RCF on wheels. It could be concluded that wheels experience relatively less RCF damage than rails. Once the two parameters were calibrated against the wheel measurements, the prediction tool showed promising results for predicting both wear and RCF and their trade-off. The predicted position of the damage on the tread of the wheel also agreed well with the position found in the measurements.
|
|
| 8. |
- Dirks, Babette, et al.
(författare)
-
The development of a crack propagation model for railway wheels and rails
- 2015
-
Ingår i: Fatigue and Fracture of Engineering Materials and Structures. - : Wiley. - 8756-758X .- 1460-2695. ; 38:12, s. 1478-1491
-
Tidskriftsartikel (refereegranskat)abstract
- Rolling contact fatigue (RCF) and wear of railway wheels and rails are the main phenom-ena that affect their m aintenance costs. When crack propagation and wear rates can bepredicted, maintenance planning can be optimised, and cost-effective measures can bedeveloped. Several RCF models exist, but none which can be used in combination withvehicle dynamics simulations and can predict the actual crack depth. This study showsthe development of a crack propagation model that can be applied for both railwaywheels and rails. Two unknow n material parameters in the model were calibrated againstcrack measurements in a curve on the Dutch railways over a period of 5 years. Two dif-ferent RCF models were used to calculate the stress magnitudes for the propagationmodel. The propagation model can be used in combination with vehicle-track dynamicssimulations and shows promise in predicting the actual crack depth and/or surface length.Further research is needed to determine the model’s validity for other operationalconditions.
|
|
| 9. |
- Li, Yuyi, et al.
(författare)
-
Influence of an alternative non-elliptic contact model on wheel wear calculation
- 2018
-
Ingår i: The Dynamics of Vehicles on Roads and Tracks. - : CRC Press. - 9781138035713 ; , s. 937-943
-
Konferensbidrag (refereegranskat)abstract
- The contact model between wheel and rail is significant for predicting wear of the wheel profile with help of multi-body dynamics simulation. Among the contact models, Hertz’s theory and Fastsim algorithm are widely used in MBS software due to high computational efficiency and acceptable precision. But with respect to wear, the accuracy of such a contact model is insufficient, especially for predicting the wear distribution. A new non-elliptic contact model called ANALYN/FaStrip with fast calculation speed has been proposed to improve the precision for both normal and tangential solutions. This paper investigates the influence of this new contact model on the wear calculation by comparing with Hertz/Fastsim in terms of contact pressure and creep forces, and finally indicates the difference of wear depth calculated by the two contact models. The results illustrate that significant improvements can be gained by implementing ANALYN/FaStrip into the wheel wear prediction.
|
|
| 10. |
- Shahzamanian Sichani, Matin, et al.
(författare)
-
An alternative to FASTSIM for tangential solution of the wheel-rail contact
- 2016
-
Ingår i: The Dynamics of Vehicles on Roads and Tracks - Proceedings of the 24th Symposium of the International Association for Vehicle System. - : CRC Press. - 9781498777025 - 9781138028852 ; , s. 1377-1385
-
Konferensbidrag (refereegranskat)abstract
- In most rail vehicle dynamics simulation packages, creep forces are estimated by means of Kalker's FASTSIM algorithm. While 5%-25% error is expected for force estimation the errors of shear stress distribution, needed for wheel/rail damage analysis, may rise above 30%. This is mainly due to the use of parabolic traction bound in FASTSIM. Thus, a novel algorithm called FaStrip is proposed as an alternative to FASTSIM. It is based on the strip theory in which elliptic traction bound is used. The comparison between the two algorithms, evaluated by CONTACT, shows that using FaStrip improves the accuracy of the estimated shear stress distribution while the creep force estimation in all studied cases is significantly improved as well. In one case, for instance, the error in force estimation reduces from 18% to less than 2%. Since FaStrip is as fast as FASTSIM, it can be an alternative for tangential solution of the wheel-rail contact in simulation packages.
|
|
| 11. |
- Shahzamanian Sichani, Matin, et al.
(författare)
-
An alternative to FASTSIM for tangential solution of the wheel–rail contact
- 2016
-
Ingår i: Vehicle System Dynamics. - : Taylor & Francis. - 0042-3114 .- 1744-5159. ; 54:6, s. 748-764
-
Tidskriftsartikel (refereegranskat)abstract
- In most rail vehicle dynamics simulation packages, tangential solution of the wheel–rail contact is gained by means of Kalker's FASTSIM algorithm. While 5–25% error is expected for creep force estimation, the errors of shear stress distribution, needed for wheel–rail damage analysis, may rise above 30% due to the parabolic traction bound. Therefore, a novel algorithm named FaStrip is proposed as an alternative to FASTSIM. It is based on the strip theory which extends the two-dimensional rolling contact solution to three-dimensional contacts. To form FaStrip, the original strip theory is amended to obtain accurate estimations for any contact ellipse size and it is combined by a numerical algorithm to handle spin. The comparison between the two algorithms shows that using FaStrip improves the accuracy of the estimated shear stress distribution and the creep force estimation in all studied cases. In combined lateral creepage and spin cases, for instance, the error in force estimation reduces from 18% to less than 2%. The estimation of the slip velocities in the slip zone, needed for wear analysis, is also studied. Since FaStrip is as fast as FASTSIM, it can be an alternative for tangential solution of the wheel–rail contact in simulation packages.
|
|
| 12. |
- Shahzamanian Sichani, Matin, 1986-
(författare)
-
On Efficient Modelling of Wheel-Rail Contact in Vehicle Dynamics Simulation
- 2016
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The wheel-rail contact is at the core of all research related to vehicletrackinteraction. This tiny interface governs the dynamic performanceof rail vehicles through the forces it transmits and, like any high stressconcentration zone, it is subjected to serious damage phenomena. Thus,a clear understanding of the rolling contact between wheel and rail is keyto realistic vehicle dynamics simulation and damage analysis.In a multi-body dynamics simulation, the demanding contact problemshould be evaluated at about every millisecond for several wheel-rail pairs.Hence, a rigorous treatment of the contact is highly time-consuming.Simplifying assumptions are therefore made to accelerate the simulationprocess. This gives rise to a trade-o between the accuracy and computationaleciency of the contact model in use.Conventionally, Hertz+FASTSIM is used for calculation of the contactforces thanks to its low computational cost. However, the elliptic patchand pressure distribution obtained by Hertz' theory is often not realisticin wheel-rail contact. Moreover, the use of parabolic traction bound inFASTSIM causes considerable error in the tangential stress estimation.This combination leads to inaccurate damage predictions.Fast non-elliptic contact models are proposed by others to tacklethis issue while avoiding the tedious numerical procedures. The studiesconducted in the present work show that the accuracy of these models iscase-dependent.To improve the accuracy of non-elliptic patch and pressure estimation,a new method is proposed. The method is implemented in an algorithmnamed ANALYN. Comparisons show improvements in patch and, particularly,pressure estimations using ANALYN.In addition, an alternative to the widely-used FASTSIM is developed, named FaStrip. Unlike FASTSIM, it employs an elliptic traction boundand is able to estimate the non-linear characteristic of tangential stressdistribution. Comparisons show more accurate estimation of tangentialstress and slip velocity distribution as well as creep forces with FaStrip.Ultimately, an ecient non-elliptic wheel-rail contact model consistingof ANALYN and FaStrip is proposed. The reasonable computationalcost of the model enables it to be used on-line in dynamics simulationand its accuracy can improve the damage predictions.
|
|
| 13. |
- Sichani, Matin Sh., et al.
(författare)
-
A fast wheel-rail contact model for application to damage analysis in vehicle dynamics simulation
- 2016
-
Ingår i: Wear. - : Elsevier. - 0043-1648 .- 1873-2577. ; 366, s. 123-130
-
Tidskriftsartikel (refereegranskat)abstract
- A novel wheel-rail contact model is proposed to be implemented for multi-body dynamics simulation, in order to facilitate accurate online calculation of damage phenomena such as wear and rolling contact fatigue. The normal contact, i.e. contact patch and pressure distribution, is calculated using a fast non elliptic algorithm called ANALYN. The tangential contact, i.e. tangential stress distribution, stick-slip division and creep force calculation, is treated using an alternative to the FASTSIM algorithm that is based on a strip theory which extends the two-dimensional solution of rolling contact to three-dimensional contacts. The proposed contact model is compared to the Hertz+FASTSIM model and evaluated using the CONTACT code in terms of contact patch and stress distribution as well as creep force curves. The results show that the proposed model can significantly improve the estimation of the contact solution both in terms of creep force estimation and contact details, such as stress distribution, needed for damage predictions.
|
|
| 14. |
- Sichani, Matin Shahzamanian, et al.
(författare)
-
Wheel-rail contact modeling for damage predictions in dynamics simulation software
- 2015
-
Ingår i: CM 2015 - 10th International Conference on Contact Mechanics of Wheel / Rail Systems. - : International Conference on Contact Mechanics of Wheel.
-
Konferensbidrag (refereegranskat)abstract
- A novel wheel-rail contact model is proposed to be implemented for multi-body dynamics simulation, in order to facilitate accurate online calculation of damage phenomena such as wear and rolling contact fatigue. The normal contact, i.e. contact patch and pressure distribution, is calculated using a fast non-elliptic algorithm called ANALYN. The tangential contact, i.e. tangential stress distribution, stick-slip division and creep force calculation, is treated using an alternative to the FASTSIM algorithm that is based on a strip theory which extends the exact two-dimensional solution of rolling contact to three-dimensional contacts. The proposed contact model is compared to the Kik-Piotrowski model and evaluated using the CONTACT code in terms of contact patch and stress distribution as well as creep force curves. The results show that the proposed model can significantly improve the estimation of the contact solution both in terms of creep force estimation and contact details, such as stress distribution, needed for damage predictions.
|
|
