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Mats Berg - One of the best experts on this subject based on the ideXlab platform.
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a novel method to model wheel rail normal Contact in vehicle dynamics simulation
Vehicle System Dynamics, 2014Co-Authors: Matin Sh Sichani, Roger Enblom, Mats BergAbstract:An approximate analytical method is proposed for calculating the Contact Patch and pressure distribution in the wheel-rail interface. The deformation of the surfaces in Contact is approximated using the separation between them. This makes it possible to estimate the Contact Patch analytically. The Contact pressure distribution in the rolling direction is assumed to be elliptic with its maximum calculated by applying Hertz' solution locally. The results are identical to Hertz's for elliptic cases. In non-elliptic cases good agreement is achieved in comparison to the more accurate but computationally expensive Kalker's variational method (Contact code). Compared to simplified non-elliptic Contact methods based on virtual penetration, the calculated Contact Patch and pressure distribution are markedly improved. The computational cost of the proposed method is significantly lower than the more detailed methods, making it worthwhile to be applied to rolling Contact in rail vehicle dynamics simulation. Such fast and accurate estimation of Contact Patch and pressure paves the way for on-line modelling of damage phenomena in dynamics simulation packages.
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A novel method to model wheel–rail normal Contact in vehicle dynamics simulation
Vehicle System Dynamics, 2014Co-Authors: Matin Sh Sichani, Roger Enblom, Mats BergAbstract:An approximate analytical method is proposed for calculating the Contact Patch and pressure distribution in the wheel-rail interface. The deformation of the surfaces in Contact is approximated using the separation between them. This makes it possible to estimate the Contact Patch analytically. The Contact pressure distribution in the rolling direction is assumed to be elliptic with its maximum calculated by applying Hertz' solution locally. The results are identical to Hertz's for elliptic cases. In non-elliptic cases good agreement is achieved in comparison to the more accurate but computationally expensive Kalker's variational method (Contact code). Compared to simplified non-elliptic Contact methods based on virtual penetration, the calculated Contact Patch and pressure distribution are markedly improved. The computational cost of the proposed method is significantly lower than the more detailed methods, making it worthwhile to be applied to rolling Contact in rail vehicle dynamics simulation. Such fast and accurate estimation of Contact Patch and pressure paves the way for on-line modelling of damage phenomena in dynamics simulation packages.
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COMPARISON OF NON-ELLIPTIC Contact MODELS: TOWARDS FAST AND ACCURATE MODELLING OF WHEEL-RAIL Contact
Wear, 2014Co-Authors: Matin Sh Sichani, Roger Enblom, Mats BergAbstract:The demand to investigate and predict the surface deterioration phenomena in the wheel–rail interface necessitates fast and accurate Contact modelling. During the past 20 years, there have been attempts to determine more realistic Contact Patch and stress distributions using fast simplified methods. The main aim of the present work is to compare some of these state-of-the-art, non-elliptic Contact models available in the literature. This is considered as the first step to develop a fast and accurate non-elliptic Contact model that can be used on-line with vehicle dynamics analysis. Three Contact models, namely STRIPES, Kik-Piotrowski and Linder are implemented and compared in terms of Contact Patch prediction, as well as Contact pressure and traction distributions. The evaluation of these models using Contact software indicate the need for improvement of Contact Patch and pressure estimation in certain Contact cases.
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Non-Elliptic Wheel-Rail Contact Modelling in Vehicle Dynamics Simulation
International Journal of Railway Technology, 2014Co-Authors: Matin Sh Sichani, Roger Enblom, Mats BergAbstract:The demand to investigate and predict the surface deterioration phenomena in the wheel–rail interface necessitates fast and accurate Contact modelling. During the past 20 years, there have been attempts to determine more realistic Contact Patch and stress distributions using fast simplified methods. The main aim of the present work is to compare some of these state-of-the-art, non-elliptic Contact models available in the literature. This is considered as the first step to develop a fast and accurate non-elliptic Contact model that can be used on-line with vehicle dynamics analysis. Three Contact models, namely STRIPES, Kik-Piotrowski and Linder are implemented and compared in terms of Contact Patch prediction, as well as Contact pressure and traction distributions. The evaluation of these models using Contact software indicate the need for improvement of Contact Patch and pressure estimation in certain Contact cases.
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Comparison of non-elliptic Contact models: Towards fast and accurate modelling of wheel–rail Contact
Wear, 2014Co-Authors: Matin Sh Sichani, Roger Enblom, Mats BergAbstract:The demand to investigate and predict the surface deterioration phenomena in the wheel–rail interface necessitates fast and accurate Contact modelling. During the past 20 years, there have been attempts to determine more realistic Contact Patch and stress distributions using fast simplified methods. The main aim of the present work is to compare some of these state-of-the-art, non-elliptic Contact models available in the literature. This is considered as the first step to develop a fast and accurate non-elliptic Contact model that can be used on-line with vehicle dynamics analysis. Three Contact models, namely STRIPES, Kik-Piotrowski and Linder are implemented and compared in terms of Contact Patch prediction, as well as Contact pressure and traction distributions. The evaluation of these models using Contact software indicate the need for improvement of Contact Patch and pressure estimation in certain Contact cases.
Antonio Carcaterra - One of the best experts on this subject based on the ideXlab platform.
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OPTYRE – A new technology for tire monitoring: Evidence of Contact Patch phenomena
Mechanical Systems and Signal Processing, 2020Co-Authors: N Roveri, Gianluca Pepe, Antonio CarcaterraAbstract:Abstract The present paper contains the description of a new technology for optical strain measurements in rolling tires. The apparatus is based on the use of Fiber Bragg Gratings sensors and light spectrum analyzer. With the help of a new analytical model, describing the tire strain during its revolution, the experiments permit, for the first time, to provide evidence of the transition along the Contact Patch between the grip and the slip regions. Moreover, the Contact Patch is identified and the experimental evidence suggests that the existing methods provide underestimated lengths.
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optyre a new technology for tire monitoring evidence of Contact Patch phenomena
Mechanical Systems and Signal Processing, 2016Co-Authors: N Roveri, Gianluca Pepe, Antonio CarcaterraAbstract:Abstract The present paper contains the description of a new technology for optical strain measurements in rolling tires. The apparatus is based on the use of Fiber Bragg Gratings sensors and light spectrum analyzer. With the help of a new analytical model, describing the tire strain during its revolution, the experiments permit, for the first time, to provide evidence of the transition along the Contact Patch between the grip and the slip regions. Moreover, the Contact Patch is identified and the experimental evidence suggests that the existing methods provide underestimated lengths.
Rob Dwyer-joyce - One of the best experts on this subject based on the ideXlab platform.
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Feasibility study for real time measurement of wheel-rail Contact using an ultrasonic array
Journal of Tribology, 2009Co-Authors: Rob Dwyer-joyce, C. A. Yao, J. B. Zhang, Roger Lewis, Bruce W DrinkwaterAbstract:Failure of a wheel-rail Contact is usually by wear or fatigue of either component. Both mechanisms depend on the state of stress, which in turn depends on size and location of the Contact Patch. In this work, the feasibility of an ultrasonic approach for measuring the Contact, real time on a rail, has been evaluated. The approach is based on the physical phenomenon of ultrasonic reflection at an interface. If the wheel and rail surfaces make Contact, and are under high stress, they will transmit an ultrasonic pulse. However, if there is no Contact, or the Contact is under low stress, then the wave is completely or partially reflected. By measuring the proportion of the wave reflected, it is possible to deduce the extent of the Contact area and also estimate the pressure distribution. In a previous work (Marshall, Lewis, Dwyer-Joyce, Olofsson, and Bjorklund, 2006, "Experimental Characterisation of Wheel-Rail Contact Patch Evolution," ASME J. Tribol., 128(3), pp. 493-504), static wheel-rail Contacts were scanned using a transducer to build up a two-dimensional (2D) map of the Contact. The procedure was time consuming and could in no way be used for measurements online. In this work, a method is presented that could be used at line speeds, and so provide wheel-rail Contact measurements in field trials. The scan is achieved by using an array transducer that performs a one dimensional electronic line scan. This, coupled with the speed of travel of the Contact Patch past the sensor location, enables a 2D map of the Contact to be produced. Specimens were cut from wheel and rail sections and loaded together hydraulically in a biaxial frame. An array transducer was mounted beneath the rail specimen. The array transducer consisted of 64 ultrasonic elements that could be pulsed independently, simultaneously, or with controlled phase difference. The signals were reflected back from the Contact to effectively produce a line scan. The transducer was physically moved to simulate the translation of the Contact Patch and so generate a series of 2D reflection profiles. Contacts under a range of normal and lateral loads have been measured and compared with some simple results using a pressure sensitive film. While the map produced by ultrasonic reflection is relatively coarse, the results agree well with measurements from the pressure sensitive film. The work concludes with a discussion of how this array measurement procedure might be implemented at full line speed, and what resolution could potentially be achieved. copyright © 2009 by ASME.
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A Rail Mounted Ultrasonic Sensor for Contact Patch Measurement
IEEE ASME ASCE 2008 Joint Rail Conference, 2008Co-Authors: Rob Dwyer-joyce, Bruce W Drinkwater, Roger Lewis, Jie ZhangAbstract:Failure of a wheel/rail Contact is usually by wear or fatigue and both of these depend on the size and location of the Contact Patch. One Contact measuring approach that shows promise is by the use of ultrasonic reflection. If the wheel and rail surfaces make Contact and are under high stress they are more likely to transmit an ultrasonic pulse. However, if there is no Contact or the Contact is under low stress then the wave is completely or partially reflected. By measuring the proportion of the wave reflected it is possible to deduce the extent of the Contact area and also estimate the pressure distribution. In previous work [1] static specimens of wheel and rail were measured by scanning a transducer to build up a 2D map of the Contact. Whilst this produced good results and agreed well with Contact modeling, it is a time consuming process (typically takes 30 minutes for a scan) and could in no way be used for the measurement on-line. In this paper we describe a method that potentially could be used at line speeds and so provide wheel rail Contact measurements in field trials. The 2D scan is achieved by using an array transducer that performs a simultaneous line scan. This coupled with the speed of travel of the Contact Patch over the sensor location can achieve a map of the Contact. Specimens were cut from wheel and rail sections and loaded together hydraulically in a biaxial frame. An array transducer was mounted beneath the rail specimen. The array transducer consisted of 64 ultrasonic elements that may be pulsed independently, simultaneously, or with controlled phase difference. In this work all transducers were pulsed simultaneously at repetition rates of 20 kHz. The signals were reflected back from the Contact to effectively produce a line scan. The transducer was physically moved, to simulate the translation of the Contact Patch and so generate a series of reflection profiles. Contacts under a range of normal and lateral loads have been measured and compared with some simple results using pre-inked paper. The paper concludes with a discussion of how this array measurement procedure might be implemented at full line sped and what accuracy could potentially be achieved.Copyright © 2008 by ASME
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Experimental characterization of wheel-rail Contact Patch evolution
Journal of Tribology, 2006Co-Authors: M B Marshall, S. Björklund, Ulf Olofsson, Rob Dwyer-joyce, Roger Lewis, Stefan BjörklundAbstract:The Contact area and pressure distribution in a wheel/rail Contact is essential information required in any fatigue or wear calculations to determine design life, re-grinding, and maintenance schedules. As wheel or rail wear or surface damage takes place the Contact Patch size and shape will change. This leads to a redistribution of the Contact stresses. The aim of this work was to use ultrasound to nondestructively quantify the stress distribution in new, worn, and damaged wheel-rail Contacts. The response of a wheel/rail interface to an ultrasonic wave can be modeled as a spring. If the Contact pressure is high the interface is very stiff, with few air gaps, and allows the transmission of an ultrasonic sound wave. If the pressure is low, interfacial stiffness is lower and almost all the ultrasound is reflected. A quasistatic spring model was used to determine maps of Contact stiffness from wheel/rail ultrasonic reflection data. Pressure was then determined using a parallel calibration experiment. Three different Contacts were investigated; those resulting from unused, worn, and sand damaged wheel and rail specimens. Measured Contact pressure distributions are compared to those determined using elastic analytical and numerical elastic-plastic solutions. Unused as-machined Contact surfaces had similar Contact areas to predicted elastic Hertzian solutions. However, within the Contact Patch, the numerical models better reproduced the stress distribution, as they incorporated real surface roughness effects. The worn surfaces were smoother and more conformal, resulting in a larger Contact Patch and lower Contact stress. Sand damaged surfaces were extremely rough and resulted in highly fragmented Contact regions and high local Contact stress. Copyright  2006 by ASME.
Gabriel Anghelache - One of the best experts on this subject based on the ideXlab platform.
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Finite Element Analyses of the Influence of Tyre Functional Parameters on Contact Patch Stresses
The 30th SIAR International Congress of Automotive and Transport Engineering, 2019Co-Authors: Alexandra-raluca Moisescu, Gabriel AnghelacheAbstract:The study of Contact Patch stresses represents an important field of research with respect to automotive safety, as well as tyre and road durability, but also concerning vehicle comfort. The finite element method is an important tool for the investigation of tyre-road Contact that provides valuable information regarding the generation of forces in the Contact Patch. The current paper presents an investigation performed on the distribution of stresses developed in the Contact Patch, using the finite element model of a 11R22.5 radial truck tyre. The analyses performed on the tyre model have emphasized the influence of various functional parameters, such as inflation pressure, camber angle and rolling speed, on the distributions of the Contact Patch stresses. The inflation pressure has an important effect on Contact Patch size and normal stress magnitudes. At lower inflation pressure the higher values of shear stress are applied on larger areas, suggesting an increase in the intensity of slip phenomena. The camber angle has an influence on the Contact Patch shape, as well as on the asymmetry of Contact stress distributions with respect to the longitudinal plane. The differences between the distributions of Contact Patch stresses at different speed values are very small, possibly due to the relatively low speed values. The comparison between the results obtained in static conditions and in rolling conditions has showed insignificant changes in the distribution of normal stresses, but it has revealed major differences concerning the magnitudes and distributions of longitudinal and lateral stresses.
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Measurement of stress distributions in truck tyre Contact Patch in real rolling conditions
Vehicle System Dynamics, 2012Co-Authors: Gabriel Anghelache, Raluca MoisescuAbstract:Stress distributions on three orthogonal directions have been measured across the Contact Patch of truck tyres using the complex measuring system that contains a transducer assembly with 30 sensing elements placed in the road surface. The measurements have been performed in straight line, in real rolling conditions. Software applications for calibration, data acquisition, and data processing were developed. The influence of changes in inflation pressure and rolling speed on the shapes and sizes of truck tyre Contact Patch has been shown. The shapes and magnitudes of normal, longitudinal, and lateral stress distributions, measured at low speed, have been presented and commented. The effect of wheel toe-in and camber on the stress distribution results was observed. The paper highlights the impact of the longitudinal tread ribs on the shear stress distributions. The ratios of stress distributions in the truck tyre Contact Patch have been computed and discussed.
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measuring system for investigation of tri axial stress distribution across the tyre road Contact Patch
Measurement, 2011Co-Authors: Gabriel Anghelache, Raluca Moisescu, ştefan Sorohan, Dorin Laurenţiu BureţeaAbstract:Abstract A measuring system for investigation of stress distributions in the tyre–road Contact Patch was designed and developed. The transducer within this system comprises a transversal array of sensing elements, covering the entire Contact Patch width in a single run. The system simultaneously measures stress distributions on three directions for a truck tyre (or even airplane tyre). Each sensing element has 10 mm × 10 mm Contact surface and optimized dimensions, allowing measurements in various wheel rolling conditions. The transducer induces minimum changes in tyre–road Contact properties, as it has very small gaps around sensing elements. The system is road mounted, in real rolling conditions. The measuring system contains 90 strain measuring channels. Main aspects regarding system calibration and specially developed software are illustrated. Preliminary results of tyre–road Contact stress distributions are presented.
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Measuring system for investigation of tri-axial stress distribution across the tyre–road Contact Patch
Measurement, 2011Co-Authors: Gabriel Anghelache, Raluca Moisescu, ştefan Sorohan, Dorin Laurenţiu BureţeaAbstract:Abstract A measuring system for investigation of stress distributions in the tyre–road Contact Patch was designed and developed. The transducer within this system comprises a transversal array of sensing elements, covering the entire Contact Patch width in a single run. The system simultaneously measures stress distributions on three directions for a truck tyre (or even airplane tyre). Each sensing element has 10 mm × 10 mm Contact surface and optimized dimensions, allowing measurements in various wheel rolling conditions. The transducer induces minimum changes in tyre–road Contact properties, as it has very small gaps around sensing elements. The system is road mounted, in real rolling conditions. The measuring system contains 90 strain measuring channels. Main aspects regarding system calibration and specially developed software are illustrated. Preliminary results of tyre–road Contact stress distributions are presented.
Matin Sh Sichani - One of the best experts on this subject based on the ideXlab platform.
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a novel method to model wheel rail normal Contact in vehicle dynamics simulation
Vehicle System Dynamics, 2014Co-Authors: Matin Sh Sichani, Roger Enblom, Mats BergAbstract:An approximate analytical method is proposed for calculating the Contact Patch and pressure distribution in the wheel-rail interface. The deformation of the surfaces in Contact is approximated using the separation between them. This makes it possible to estimate the Contact Patch analytically. The Contact pressure distribution in the rolling direction is assumed to be elliptic with its maximum calculated by applying Hertz' solution locally. The results are identical to Hertz's for elliptic cases. In non-elliptic cases good agreement is achieved in comparison to the more accurate but computationally expensive Kalker's variational method (Contact code). Compared to simplified non-elliptic Contact methods based on virtual penetration, the calculated Contact Patch and pressure distribution are markedly improved. The computational cost of the proposed method is significantly lower than the more detailed methods, making it worthwhile to be applied to rolling Contact in rail vehicle dynamics simulation. Such fast and accurate estimation of Contact Patch and pressure paves the way for on-line modelling of damage phenomena in dynamics simulation packages.
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A novel method to model wheel–rail normal Contact in vehicle dynamics simulation
Vehicle System Dynamics, 2014Co-Authors: Matin Sh Sichani, Roger Enblom, Mats BergAbstract:An approximate analytical method is proposed for calculating the Contact Patch and pressure distribution in the wheel-rail interface. The deformation of the surfaces in Contact is approximated using the separation between them. This makes it possible to estimate the Contact Patch analytically. The Contact pressure distribution in the rolling direction is assumed to be elliptic with its maximum calculated by applying Hertz' solution locally. The results are identical to Hertz's for elliptic cases. In non-elliptic cases good agreement is achieved in comparison to the more accurate but computationally expensive Kalker's variational method (Contact code). Compared to simplified non-elliptic Contact methods based on virtual penetration, the calculated Contact Patch and pressure distribution are markedly improved. The computational cost of the proposed method is significantly lower than the more detailed methods, making it worthwhile to be applied to rolling Contact in rail vehicle dynamics simulation. Such fast and accurate estimation of Contact Patch and pressure paves the way for on-line modelling of damage phenomena in dynamics simulation packages.
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COMPARISON OF NON-ELLIPTIC Contact MODELS: TOWARDS FAST AND ACCURATE MODELLING OF WHEEL-RAIL Contact
Wear, 2014Co-Authors: Matin Sh Sichani, Roger Enblom, Mats BergAbstract:The demand to investigate and predict the surface deterioration phenomena in the wheel–rail interface necessitates fast and accurate Contact modelling. During the past 20 years, there have been attempts to determine more realistic Contact Patch and stress distributions using fast simplified methods. The main aim of the present work is to compare some of these state-of-the-art, non-elliptic Contact models available in the literature. This is considered as the first step to develop a fast and accurate non-elliptic Contact model that can be used on-line with vehicle dynamics analysis. Three Contact models, namely STRIPES, Kik-Piotrowski and Linder are implemented and compared in terms of Contact Patch prediction, as well as Contact pressure and traction distributions. The evaluation of these models using Contact software indicate the need for improvement of Contact Patch and pressure estimation in certain Contact cases.
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Non-Elliptic Wheel-Rail Contact Modelling in Vehicle Dynamics Simulation
International Journal of Railway Technology, 2014Co-Authors: Matin Sh Sichani, Roger Enblom, Mats BergAbstract:The demand to investigate and predict the surface deterioration phenomena in the wheel–rail interface necessitates fast and accurate Contact modelling. During the past 20 years, there have been attempts to determine more realistic Contact Patch and stress distributions using fast simplified methods. The main aim of the present work is to compare some of these state-of-the-art, non-elliptic Contact models available in the literature. This is considered as the first step to develop a fast and accurate non-elliptic Contact model that can be used on-line with vehicle dynamics analysis. Three Contact models, namely STRIPES, Kik-Piotrowski and Linder are implemented and compared in terms of Contact Patch prediction, as well as Contact pressure and traction distributions. The evaluation of these models using Contact software indicate the need for improvement of Contact Patch and pressure estimation in certain Contact cases.
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Comparison of non-elliptic Contact models: Towards fast and accurate modelling of wheel–rail Contact
Wear, 2014Co-Authors: Matin Sh Sichani, Roger Enblom, Mats BergAbstract:The demand to investigate and predict the surface deterioration phenomena in the wheel–rail interface necessitates fast and accurate Contact modelling. During the past 20 years, there have been attempts to determine more realistic Contact Patch and stress distributions using fast simplified methods. The main aim of the present work is to compare some of these state-of-the-art, non-elliptic Contact models available in the literature. This is considered as the first step to develop a fast and accurate non-elliptic Contact model that can be used on-line with vehicle dynamics analysis. Three Contact models, namely STRIPES, Kik-Piotrowski and Linder are implemented and compared in terms of Contact Patch prediction, as well as Contact pressure and traction distributions. The evaluation of these models using Contact software indicate the need for improvement of Contact Patch and pressure estimation in certain Contact cases.