The Experts below are selected from a list of 1308 Experts worldwide ranked by ideXlab platform

Ulf Sellgren - One of the best experts on this subject based on the ideXlab platform.

  • Pin-on-disc study of the effects of railway friction modifiers on airborne wear particles from wheel-rail Contacts
    Tribology International, 2013
    Co-Authors: Saeed Abbasi, Yi Zhu, Ulf Olofsson, Ulf Sellgren
    Abstract:

    Knowledge of wheel-rail interaction is crucial to wheel and rail maintenance. In this interaction, some of the worn-off material is transformed into airborne particles. Although such wear is well understood, few studies treat the particles generated. We investigated friction modifiers' effects on airborne particle characteristics generated in wheel-rail Contacts in laboratory conditions. Pin-on-disc machine testing with a round-head pin loaded by a dead weight load 40 N simulated Maximum Contact Pressure over 550 MPa. Airborne particle characteristics were investigated in dry Contacts and in ones lubricated with biodegradable rail grease and water- and oil-based friction modifiers. The number of particles declined with the grease; the number of ultrafine particles increased with the water-based friction modifier, mainly due to water vaporization. © 2012 Elsevier Ltd.

Xuesong Jin - One of the best experts on this subject based on the ideXlab platform.

  • analysis of wheel and rail adhesion under wet condition by using elastic plastic microContact model wheel rail adhesion wet condition e p deformation and temperature
    Lubrication Science, 2015
    Co-Authors: Bing Wu, Zefeng Wen, Hengyu Wang, Xuesong Jin
    Abstract:

    This paper presents a numerical model to investigate the adhesion characteristics of the wheel/rail Contact with consideration of surface roughness under wet conditions. The elastohydrodynamic lubrication theory is used to obtain the load carried by water, and the statistical elastic–plastic microContact model presented by Zhao–Maietta–Chang is applied to calculate the load carried by asperities Contact. Meanwhile, the thermal influencing reduction factor is used to consider the inlet heating effects on the film thickness, and the change of water viscosity is also taken into consideration due to the flash temperature generated by the moving rough surfaces. Furthermore, the present work investigates the dependence of the wheel/rail adhesion coefficient on train speed, surface roughness amplitude, the initial temperature, the plasticity index and the Maximum Contact Pressure under wet condition. Copyright © 2014 John Wiley & Sons, Ltd.

  • Analysis of wheel and rail adhesion under wet condition by using elastic-plastic microContact model
    Lubrication Science, 2015
    Co-Authors: Bing Wu, Zefeng Wen, Hengyu Wang, Xuesong Jin
    Abstract:

    © 2014 John Wiley & Sons, Ltd. This paper presents a numerical model to investigate the adhesion characteristics of the wheel/rail Contact with consideration of surface roughness under wet conditions. The elastohydrodynamic lubrication theory is used to obtain the load carried by water, and the statistical elastic-plastic microContact model presented by Zhao-Maietta-Chang is applied to calculate the load carried by asperities Contact. Meanwhile, the thermal influencing reduction factor is used to consider the inlet heating effects on the film thickness, and the change of water viscosity is also taken into consideration due to the flash temperature generated by the moving rough surfaces. Furthermore, the present work investigates the dependence of the wheel/rail adhesion coefficient on train speed, surface roughness amplitude, the initial temperature, the plasticity index and the Maximum Contact Pressure under wet condition.

  • Analysis of wheel and rail adhesion under wet condition by using elastic-plastic microContact model: WHEEL/RAIL ADHESION WET CONDITION E-P DEFORMATION AND TEMPERATURE
    Lubrication Science, 2014
    Co-Authors: Bing Wu, Zefeng Wen, Hengyu Wang, Xuesong Jin
    Abstract:

    This paper presents a numerical model to investigate the adhesion characteristics of the wheel/rail Contact with consideration of surface roughness under wet conditions. The elastohydrodynamic lubrication theory is used to obtain the load carried by water, and the statistical elastic–plastic microContact model presented by Zhao–Maietta–Chang is applied to calculate the load carried by asperities Contact. Meanwhile, the thermal influencing reduction factor is used to consider the inlet heating effects on the film thickness, and the change of water viscosity is also taken into consideration due to the flash temperature generated by the moving rough surfaces. Furthermore, the present work investigates the dependence of the wheel/rail adhesion coefficient on train speed, surface roughness amplitude, the initial temperature, the plasticity index and the Maximum Contact Pressure under wet condition. Copyright © 2014 John Wiley & Sons, Ltd.

Dongfeng Diao - One of the best experts on this subject based on the ideXlab platform.

  • finite element analysis on local yield map and critical Maximum Contact Pressure for yielding in hard coating with an interlayer under sliding Contact
    Tribology International, 1999
    Co-Authors: Dongfeng Diao
    Abstract:

    Abstract Micro-crack in the hard coating initiates usually from the local yield position. To prevent the crack to occur, the most important criterion is to satisfy the condition that the von Mises stress is less than the yield strength of material. In this paper, the local yield map showing the yielding position are introduced by using the finite element method and the criterion. The critical Maximum Contact Pressures for yielding at the different positions were calculated by using the coating thickness, friction coefficient and the yield strength, where a critical range of yield strength ratio for the transition of yielding positions was found for 0.4∼0.5. When the yield strength ratio is less than the range, yielding initiates from the interlayer and when the ratio is larger than the range, yielding initiates at the surface for high friction coefficient and in the base for low friction coefficient.

  • The Maximum tensile stres on a hard coating under sliding friction
    Tribology International, 1994
    Co-Authors: Dongfeng Diao, Koji Kato, K. Hayashi
    Abstract:

    Abstract In the friction of a hard coating the Maximum tensile stress in the sliding direction generated at the friction surface is important for predicting crack propagation in the coating. The finite element method is employed to evaluate the stress field in the hard coating and the substrate under frictional loads, and the ratio between the values of Maximum tensile stress and the Maximum Contact Pressure is calculated under various Contact conditions. Finally, a simple equation is introduced for the calculation of the Maximum tensile stress at the friction surface. This equation is a function of friction coefficient, Maximum Contact Pressure, coating thickness, Contact width and elastic moduli of coating and substrate, and gives the value of the Maximum tensile stress which is affected by the existence of the substrate.

Saeed Abbasi - One of the best experts on this subject based on the ideXlab platform.

  • Pin-on-disc study of the effects of railway friction modifiers on airborne wear particles from wheel-rail Contacts
    Tribology International, 2013
    Co-Authors: Saeed Abbasi, Yi Zhu, Ulf Olofsson, Ulf Sellgren
    Abstract:

    Knowledge of wheel-rail interaction is crucial to wheel and rail maintenance. In this interaction, some of the worn-off material is transformed into airborne particles. Although such wear is well understood, few studies treat the particles generated. We investigated friction modifiers' effects on airborne particle characteristics generated in wheel-rail Contacts in laboratory conditions. Pin-on-disc machine testing with a round-head pin loaded by a dead weight load 40 N simulated Maximum Contact Pressure over 550 MPa. Airborne particle characteristics were investigated in dry Contacts and in ones lubricated with biodegradable rail grease and water- and oil-based friction modifiers. The number of particles declined with the grease; the number of ultrafine particles increased with the water-based friction modifier, mainly due to water vaporization. © 2012 Elsevier Ltd.

Bing Wu - One of the best experts on this subject based on the ideXlab platform.

  • analysis of wheel and rail adhesion under wet condition by using elastic plastic microContact model wheel rail adhesion wet condition e p deformation and temperature
    Lubrication Science, 2015
    Co-Authors: Bing Wu, Zefeng Wen, Hengyu Wang, Xuesong Jin
    Abstract:

    This paper presents a numerical model to investigate the adhesion characteristics of the wheel/rail Contact with consideration of surface roughness under wet conditions. The elastohydrodynamic lubrication theory is used to obtain the load carried by water, and the statistical elastic–plastic microContact model presented by Zhao–Maietta–Chang is applied to calculate the load carried by asperities Contact. Meanwhile, the thermal influencing reduction factor is used to consider the inlet heating effects on the film thickness, and the change of water viscosity is also taken into consideration due to the flash temperature generated by the moving rough surfaces. Furthermore, the present work investigates the dependence of the wheel/rail adhesion coefficient on train speed, surface roughness amplitude, the initial temperature, the plasticity index and the Maximum Contact Pressure under wet condition. Copyright © 2014 John Wiley & Sons, Ltd.

  • Analysis of wheel and rail adhesion under wet condition by using elastic-plastic microContact model
    Lubrication Science, 2015
    Co-Authors: Bing Wu, Zefeng Wen, Hengyu Wang, Xuesong Jin
    Abstract:

    © 2014 John Wiley & Sons, Ltd. This paper presents a numerical model to investigate the adhesion characteristics of the wheel/rail Contact with consideration of surface roughness under wet conditions. The elastohydrodynamic lubrication theory is used to obtain the load carried by water, and the statistical elastic-plastic microContact model presented by Zhao-Maietta-Chang is applied to calculate the load carried by asperities Contact. Meanwhile, the thermal influencing reduction factor is used to consider the inlet heating effects on the film thickness, and the change of water viscosity is also taken into consideration due to the flash temperature generated by the moving rough surfaces. Furthermore, the present work investigates the dependence of the wheel/rail adhesion coefficient on train speed, surface roughness amplitude, the initial temperature, the plasticity index and the Maximum Contact Pressure under wet condition.

  • Analysis of wheel and rail adhesion under wet condition by using elastic-plastic microContact model: WHEEL/RAIL ADHESION WET CONDITION E-P DEFORMATION AND TEMPERATURE
    Lubrication Science, 2014
    Co-Authors: Bing Wu, Zefeng Wen, Hengyu Wang, Xuesong Jin
    Abstract:

    This paper presents a numerical model to investigate the adhesion characteristics of the wheel/rail Contact with consideration of surface roughness under wet conditions. The elastohydrodynamic lubrication theory is used to obtain the load carried by water, and the statistical elastic–plastic microContact model presented by Zhao–Maietta–Chang is applied to calculate the load carried by asperities Contact. Meanwhile, the thermal influencing reduction factor is used to consider the inlet heating effects on the film thickness, and the change of water viscosity is also taken into consideration due to the flash temperature generated by the moving rough surfaces. Furthermore, the present work investigates the dependence of the wheel/rail adhesion coefficient on train speed, surface roughness amplitude, the initial temperature, the plasticity index and the Maximum Contact Pressure under wet condition. Copyright © 2014 John Wiley & Sons, Ltd.