The Experts below are selected from a list of 129 Experts worldwide ranked by ideXlab platform
M Hadfield - One of the best experts on this subject based on the ideXlab platform.
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subsurface propagation of partial Ring Cracks under rolling contact part ii fracture mechanics analysis
Wear, 2006Co-Authors: P Zhao, M Hadfield, Y Wang, Charlotte VieillardAbstract:Abstract Surface Ring Crack defects are normally found on the surfaces of ceramic balls. These Ring Cracks are circular extending for approximately one quarter of circumference of a circle and these Cracks can significantly reduce rolling contact fatigue life. In this study, a boundary element analysis was carried out to identify the main factors governing the propagation of sub-surface Cracks. The calculations of the main stress intensity factors (SIF), K I and K II , were made to determine which factors were important for Crack propagation. Various geometries of the Ring Crack were selected to investigate their effect on the subsurface propagation of the Ring Crack and calculated results showed the most important factor of Crack geometry was shown to be the subsurface Crack length with Crack radius. Crack angle and arc length was shown to have relatively little effect. The K II values were mainly affected by load, Crack length and Crack face friction. Increasing the load or Crack length resulted in an increase in absolute K II values, but high Crack face friction led to lower K II . Lubricants with less ability to penetrate a Crack and thereby increase Crack face friction should therefore give a better rolling contact fatigue performance. The numerical results were verified by a comprehensive experimental study [20] , which show that present predictions of subsurface Crack growth are consistent with the experimental observations.
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ceramic rolling elements with Ring Crack defects a residual stress approach
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2005Co-Authors: Zulfiqar Ahmad Khan, M Hadfield, Shogo Tobe, Y WangAbstract:Abstract Experimental results of rolling contact fatigue on ceramic beaRing elements with refrigerant lubrication are presented. Residual stress measurements located on the contact path and other locations on the surface are described. An X-ray method was employed. Residual stress measurements are helpful in predicting rolling contact fatigue life. In addition, analysing the relationship of residual stress with rolling contact fatigue is an important study, which will provide guidelines on the design, process and manufactuRing of these elements. DuRing this research, Ring Crack defects were induced in ceramic rolling contact beaRing elements. A compressive residual stress value of −73 MPa near the Ring Crack and a comparatively lower value of −12 MPa on the contact indicate sub-surface Crack initiation and propagation. The average fatigue spall ranges from 100 to 148 μm in depth. Within the spall area residual stress measurements suggest that compressive residual stress is relieved much faster in the region of sub-surface damage.
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the influence of Ring Crack location on the rolling contact fatigue failure of lubricated silicon nitride fracture mechanics analysis
Wear, 2000Co-Authors: Y Wang, M HadfieldAbstract:The influence of Ring Crack location within the contact path on rolling contact fatigue failure has been studied using numerical fracture analysis. The numerical calculations are based on a three-dimensional model for the Ring Crack propagation. The Ring Crack is considered as a conic shape with a curved line as the Crack front. The rolling contact loading is simulated by repeated Hertzian point contact load with normal pressure and tangential traction. Fracture mechanics analysis is utilised to determine the stress intensity factors (SIFs) along the Crack front and the SIFs are analysed using a three-dimensional boundary element model. The analytical results are verified by experimental studies, which show that present predictions of Ring Crack location influence are consistent with the experimental observations.
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the influence of Ring Crack location on the rolling contact fatigue failure of lubricated silicon nitride experimental studies
Wear, 2000Co-Authors: Y Wang, M HadfieldAbstract:This paper presents an experimental study of the influences of Ring Crack location within the contact path on the rolling contact fatigue failure. The rolling contact tests are performed on silicon nitride/steel elements. Silicon nitride ball surfaces are examined before testing using a dye-penetrant technique and light microscopy. The surfaces duRing testing, post-test and after failure are examined using light microscopy. Research shows that fatigue failure under rolling contact loading is markedly sensitive to the location of Ring Crack on the contact track. Only a few locations on the contact track can lead to fatigue failure at the maximum Hertz contact pressure of 5.58 GPa.
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rolling contact fatigue failure modes of lubricated silicon nitride in relation to Ring Crack defects
Wear, 1999Co-Authors: Y Wang, M HadfieldAbstract:The use of silicon nitride applied to rolling element beaRings shows some practical advantages over traditional beaRing steels. The contribution of this present study is to provide understanding of surface Crack defect characteristics and the subsequent rolling fatigue modes of failure. Surface defects such as pressing faults and Ring Cracks are characterised using light microscopy. Experimental bench testing using an accelerated rolling contact fatigue rig produces results which identify the relationship between fatigue failure modes and surface defects. The rolling contact tests are performed on silicon nitride/steel elements using a variety of lubricants. Ball surfaces are examined before testing using a dye-penetrant technique and light microscopy. Post-test surfaces and failures are examined using light and scanning electron microscopy. A model of surface Crack propagation in lubricated contact is described. The boundary element model is used to investigate the growth mechanism of Ring Crack defects duRing rolling contact.
Y Wang - One of the best experts on this subject based on the ideXlab platform.
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ceramic rolling elements with Ring Crack defects a residual stress approach
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2005Co-Authors: Zulfiqar Ahmad Khan, M Hadfield, Shogo Tobe, Y WangAbstract:Abstract Experimental results of rolling contact fatigue on ceramic beaRing elements with refrigerant lubrication are presented. Residual stress measurements located on the contact path and other locations on the surface are described. An X-ray method was employed. Residual stress measurements are helpful in predicting rolling contact fatigue life. In addition, analysing the relationship of residual stress with rolling contact fatigue is an important study, which will provide guidelines on the design, process and manufactuRing of these elements. DuRing this research, Ring Crack defects were induced in ceramic rolling contact beaRing elements. A compressive residual stress value of −73 MPa near the Ring Crack and a comparatively lower value of −12 MPa on the contact indicate sub-surface Crack initiation and propagation. The average fatigue spall ranges from 100 to 148 μm in depth. Within the spall area residual stress measurements suggest that compressive residual stress is relieved much faster in the region of sub-surface damage.
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Ring Crack propagation in silicon nitride under rolling contact
Wear, 2001Co-Authors: Y Wang, Mark HadfieldAbstract:Abstract Silicon nitride has been found to have the optimum combination of properties which are suitable for rolling element beaRing applications to withstand high loads, severe environments, and high speeds. Surface Ring Cracks are difficult to detect but are found on the surface of silicon nitride balls. These Ring Crack defects decrease the rolling contact fatigue life considerably. This paper presents an experimental study and numerical analysis of Ring Crack propagation in rolling contact. The contribution of this study is to provide understanding of Ring Crack propagation behaviour and life prediction in rolling contact. Rolling contact tests are performed on the silicon nitride/steel elements. Silicon nitride ball surfaces are examined before testing using a dye-penetrant technique and optical microscopy. The surfaces are examined using optical microscopy and scanning electron microscopy duRing testing and after failure. The numerical calculations are based on a 3D model of Ring Crack growth. The rolling contact loading is simulated by a repeated Hertzian surface load with normal pressure and tangential traction. Fracture mechanics analysis is utilised to determine the stress intensity along the Crack front and the stress intensity factors are analysed using a 3D boundary element model. Life predictions from the present calculations are in line with the experimental observations.
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the influence of Ring Crack location on the rolling contact fatigue failure of lubricated silicon nitride fracture mechanics analysis
Wear, 2000Co-Authors: Y Wang, M HadfieldAbstract:The influence of Ring Crack location within the contact path on rolling contact fatigue failure has been studied using numerical fracture analysis. The numerical calculations are based on a three-dimensional model for the Ring Crack propagation. The Ring Crack is considered as a conic shape with a curved line as the Crack front. The rolling contact loading is simulated by repeated Hertzian point contact load with normal pressure and tangential traction. Fracture mechanics analysis is utilised to determine the stress intensity factors (SIFs) along the Crack front and the SIFs are analysed using a three-dimensional boundary element model. The analytical results are verified by experimental studies, which show that present predictions of Ring Crack location influence are consistent with the experimental observations.
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the influence of Ring Crack location on the rolling contact fatigue failure of lubricated silicon nitride experimental studies
Wear, 2000Co-Authors: Y Wang, M HadfieldAbstract:This paper presents an experimental study of the influences of Ring Crack location within the contact path on the rolling contact fatigue failure. The rolling contact tests are performed on silicon nitride/steel elements. Silicon nitride ball surfaces are examined before testing using a dye-penetrant technique and light microscopy. The surfaces duRing testing, post-test and after failure are examined using light microscopy. Research shows that fatigue failure under rolling contact loading is markedly sensitive to the location of Ring Crack on the contact track. Only a few locations on the contact track can lead to fatigue failure at the maximum Hertz contact pressure of 5.58 GPa.
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rolling contact fatigue failure modes of lubricated silicon nitride in relation to Ring Crack defects
Wear, 1999Co-Authors: Y Wang, M HadfieldAbstract:The use of silicon nitride applied to rolling element beaRings shows some practical advantages over traditional beaRing steels. The contribution of this present study is to provide understanding of surface Crack defect characteristics and the subsequent rolling fatigue modes of failure. Surface defects such as pressing faults and Ring Cracks are characterised using light microscopy. Experimental bench testing using an accelerated rolling contact fatigue rig produces results which identify the relationship between fatigue failure modes and surface defects. The rolling contact tests are performed on silicon nitride/steel elements using a variety of lubricants. Ball surfaces are examined before testing using a dye-penetrant technique and light microscopy. Post-test surfaces and failures are examined using light and scanning electron microscopy. A model of surface Crack propagation in lubricated contact is described. The boundary element model is used to investigate the growth mechanism of Ring Crack defects duRing rolling contact.
Osama M Jadaan - One of the best experts on this subject based on the ideXlab platform.
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weibull effective area for hertzian Ring Crack initiation
International Journal of Applied Ceramic Technology, 2011Co-Authors: Osama M Jadaan, Andrew A Wereszczak, Kurt E Johanns, William L DalozAbstract:Spherical or Hertzian indentation is used to characterize and guide the development of engineered ceramics under consideration for diverse applications involving contact, wear, rolling fatigue, and impact. Ring Crack initiation can be one important damage mechanism of Hertzian indentation. It is caused by surface-located, radial tensile stresses in an annular Ring located adjacent to and outside the Hertzian contact circle. While the maximum radial tensile stress is known to be dependent on the elastic properties of the sphere and target, diameter of the sphere, applied compressive force, and coefficient of friction, the Weibull effective area too will be affected by these parameters. However, estimations of a maximum radial tensile stress and Weibull effective area are difficult to obtain because the coefficient of friction duRing indentation is not known a priori. Circumventing this, the Weibull effective area expressions are derived here for the two extremes that bracket all coefficients of friction; namely (1) the classical, pure-slip frictionless case and (2) the case of an infinite coefficient of friction or pure stick.
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effect of indenter elastic modulus on hertzian Ring Crack initiation in silicon carbide
International Journal of Applied Ceramic Technology, 2011Co-Authors: Andrew A Wereszczak, Kevin T Strong, William L Daloz, Osama M JadaanAbstract:Hertzian Ring Cracking in two SiCs was studied as a function of elastic property mismatch between indenter and target. Ring Crack initiation forces (RCIF) were measured using ZrO2, steel, Si3N4, Al2O3, and WC balls. The SiCs were similar; however, ∼20% of the grains in one were larger than the largest grains in the other. Decreasing indenter stiffness resulted in lower RCIFs and initiation occurred at lower forces in the SiC containing larger grains. Using a spherical indenter with similar elastic properties as the target provides a simpler interpretation and useful and confident estimates of Ring Crack initiation stresses.
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indenter elastic modulus and hertzian Ring Crack initiation
2010Co-Authors: Kevin T Strong, Andrew A Wereszczak, William L Daloz, Osama M JadaanAbstract:Hertzian Ring Crack initiation was studied in several brittle materials using spherical indenters made from different materials. Target materials included silicon carbide, silicon nitride, and borosilicate glass. Indenter materials included glass, zirconia, steel, silicon nitride, alumina, and tungsten carbide. Decreasing the elastic modulus of the indenter against every one of the target materials resulted in the target material exhibiting Ring Crack initiation at lower forces. The trend is consistent and conclusive. This response is described in regards to the Poisson's mismatch between indenter and target and the associated friction effects that it produces.
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hertzian Ring Crack initiation in hot pressed silicon carbides
Journal of the American Ceramic Society, 2009Co-Authors: Andrew A Wereszczak, Kurt E Johanns, Osama M JadaanAbstract:The use of Hertzian indentation to measure Ring Crack initiation force (RCIF) distributions in four hot-pressed silicon carbide (SiC) ceramics is described. Three diamond indenter diameters were used with each SiC; the RCIF in each test was identified with the aid of an acoustic emission system; and two-parameter Weibull RCIF distributions were determined for all 12 combinations. RCIF testing was found to be an effective discriminator of contact damage initiation and response. It consistently produced the same ranking of RCIF between the four SiCs, with all three different indenter diameters, which is noteworthy because Knoop hardness and fracture toughness measurements were only subtly different or equivalent for the four SiCs. However, because RCIF, like hardness, is a characteristic response of a target material to an applied indentation condition (e.g., a function of indenter diameter) and not a material property, the implications and possible limitations should be acknowledged when using RCIF to discriminate the target material response.
S. Horton - One of the best experts on this subject based on the ideXlab platform.
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Failure modes of ceramic elements with Ring-Crack defects
Tribology International, 1993Co-Authors: Mark Hadfield, R. T. Cundill, T A Stolarski, S. HortonAbstract:A hybrid ceramic/steel angular contact ball beaRing is experimentally modelled using a modified four-ball machine. Ceramic ball surfaces are artificially damaged with Ring pre-Cracks. Rolling contact fatigue failure modes are studied after testing with high contact stresses and speeds. The ceramic ball surface and subsurface are analysed in detail using electron microscopy and a dye-penetration technique. © 1993.
Mark Hadfield - One of the best experts on this subject based on the ideXlab platform.
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Ring Crack propagation in silicon nitride under rolling contact
Wear, 2001Co-Authors: Y Wang, Mark HadfieldAbstract:Abstract Silicon nitride has been found to have the optimum combination of properties which are suitable for rolling element beaRing applications to withstand high loads, severe environments, and high speeds. Surface Ring Cracks are difficult to detect but are found on the surface of silicon nitride balls. These Ring Crack defects decrease the rolling contact fatigue life considerably. This paper presents an experimental study and numerical analysis of Ring Crack propagation in rolling contact. The contribution of this study is to provide understanding of Ring Crack propagation behaviour and life prediction in rolling contact. Rolling contact tests are performed on the silicon nitride/steel elements. Silicon nitride ball surfaces are examined before testing using a dye-penetrant technique and optical microscopy. The surfaces are examined using optical microscopy and scanning electron microscopy duRing testing and after failure. The numerical calculations are based on a 3D model of Ring Crack growth. The rolling contact loading is simulated by a repeated Hertzian surface load with normal pressure and tangential traction. Fracture mechanics analysis is utilised to determine the stress intensity along the Crack front and the stress intensity factors are analysed using a 3D boundary element model. Life predictions from the present calculations are in line with the experimental observations.
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Failure modes of ceramic elements with Ring-Crack defects
Tribology International, 1993Co-Authors: Mark Hadfield, R. T. Cundill, T A Stolarski, S. HortonAbstract:A hybrid ceramic/steel angular contact ball beaRing is experimentally modelled using a modified four-ball machine. Ceramic ball surfaces are artificially damaged with Ring pre-Cracks. Rolling contact fatigue failure modes are studied after testing with high contact stresses and speeds. The ceramic ball surface and subsurface are analysed in detail using electron microscopy and a dye-penetration technique. © 1993.
