The Experts below are selected from a list of 495 Experts worldwide ranked by ideXlab platform
Agnieszka Chudzik - One of the best experts on this subject based on the ideXlab platform.
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fatigue life prediction of the radial Roller bearing with the correction of Roller generators
International Journal of Mechanical Sciences, 2014Co-Authors: Bogdan Warda, Agnieszka ChudzikAbstract:Abstract The paper presents the methodology of fatigue life prediction of radial Cylindrical Roller Bearings, which allows to take into account in the fatigue life calculation geometric parameters of the bearing, including radial clearance and the profiles of Rollers. In addition, the methodology takes into account the effect of combined load and misalignment of the bearing rings on the fatigue life. The stress distributions which are necessary to calculate the predicted fatigue life were determined by solving numerically the Boussinesq problem for elastic half-space. The Lundberg and Palmgren model was used for the calculation of the predicted fatigue life of the bearing. The paper focuses on determining the effect of Roller profiles on the bearing fatigue life. Pressure distributions obtained by the described methodology were compared to the distributions determined according to the finite element method. The calculated fatigue life of Cylindrical Roller bearing was compared with the experimental results.
Minqing Jing - One of the best experts on this subject based on the ideXlab platform.
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an improved ultrasonic method for lubricant film thickness measurement in Cylindrical Roller Bearings under light radial load
Tribology International, 2014Co-Authors: Minqing Jing, Zengfa Che, Heng LiuAbstract:Abstract Focusing on measuring the oil-film thickness with ultrasonic approaches in Roller Bearings, a new feasible method is proposed to improve the measuring accuracy. The spatial resolution, which has great influence on the measuring accuracy, is mainly determined by the focus size of the ultrasound transducer. Under the light load conditions, the width of the Hertz contact area is smaller than the focus size, which results in overlapping measurement regions by the high pulse-repetition frequency and then brings about large measurement errors. By introducing reflection coefficients of sound pressure in the non-overlapping areas, the new method improves the measuring accuracy successfully. The experimental results are achieved from the real-time lubricant-film thickness monitoring system for Cylindrical Roller Bearings, which show good agreement with the theoretical solutions.
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Ultrasound measurement of lubricant-film thickness distribution in Cylindrical Roller Bearings
2013 IEEE International Symposium on Assembly and Manufacturing (ISAM), 2013Co-Authors: Meng Li, Minqing Jing, Zengfan ChenAbstract:In this paper, a ultrasonic method for measuring the Cylindrical Roller bearing lubricant film thickness distribution is presented. And the test bench and the high-frequency ultrasound signal acquisition and analysis system have been designed and initially built for the real-time measurement of the Cylindrical Roller bearing lubricant film thickness distribution in the industry condition. The minimum lubricant-film thickness measured by 50MHz broadband ultrasonic probe are described at high radial loads and low rotary speeds for proving the feasibility and the reliability of the system.
Heng Liu - One of the best experts on this subject based on the ideXlab platform.
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an improved ultrasonic method for lubricant film thickness measurement in Cylindrical Roller Bearings under light radial load
Tribology International, 2014Co-Authors: Minqing Jing, Zengfa Che, Heng LiuAbstract:Abstract Focusing on measuring the oil-film thickness with ultrasonic approaches in Roller Bearings, a new feasible method is proposed to improve the measuring accuracy. The spatial resolution, which has great influence on the measuring accuracy, is mainly determined by the focus size of the ultrasound transducer. Under the light load conditions, the width of the Hertz contact area is smaller than the focus size, which results in overlapping measurement regions by the high pulse-repetition frequency and then brings about large measurement errors. By introducing reflection coefficients of sound pressure in the non-overlapping areas, the new method improves the measuring accuracy successfully. The experimental results are achieved from the real-time lubricant-film thickness monitoring system for Cylindrical Roller Bearings, which show good agreement with the theoretical solutions.
Bogdan Warda - One of the best experts on this subject based on the ideXlab platform.
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fatigue life prediction of the radial Roller bearing with the correction of Roller generators
International Journal of Mechanical Sciences, 2014Co-Authors: Bogdan Warda, Agnieszka ChudzikAbstract:Abstract The paper presents the methodology of fatigue life prediction of radial Cylindrical Roller Bearings, which allows to take into account in the fatigue life calculation geometric parameters of the bearing, including radial clearance and the profiles of Rollers. In addition, the methodology takes into account the effect of combined load and misalignment of the bearing rings on the fatigue life. The stress distributions which are necessary to calculate the predicted fatigue life were determined by solving numerically the Boussinesq problem for elastic half-space. The Lundberg and Palmgren model was used for the calculation of the predicted fatigue life of the bearing. The paper focuses on determining the effect of Roller profiles on the bearing fatigue life. Pressure distributions obtained by the described methodology were compared to the distributions determined according to the finite element method. The calculated fatigue life of Cylindrical Roller bearing was compared with the experimental results.
Zaretsky Erwin - One of the best experts on this subject based on the ideXlab platform.
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Effect of Roller Geometry on Roller Bearing Load-Life Relation
2015Co-Authors: Zaretsky Erwin, Oswald, Fred B., Poplawski JosephAbstract:Cylindrical Roller Bearings typically employ Roller profile modification to equalize load distribution, minimize stress concentration at Roller ends and allow for a small amount of misalignment. The 1947 Lundberg-Palmgren analysis reported an inverse fourth power relation between load and life for Roller Bearings with line contact. In 1952, Lundberg and Palmgren changed their load-life exponent to 10/3 for Roller Bearings, assuming mixed line and point contact. The effect of Roller-crown profile was reanalyzed in this paper to determine the actual load-life relation for modified Roller profiles. For uncrowned Rollers (line contact), the load-life exponent is p = 4, in agreement with the 1947 Lundberg-Palmgren value but crowning reduces the value of the exponent, p. The lives of modern Roller Bearings made from vacuum-processed steels significantly exceed those predicted by the Lundberg-Palmgren theory. The Zaretsky rolling-element bearing life model of 1996 produces a load-life exponent of p = 5 for flat Rollers, which is more consistent with test data. For the Zaretsky model with fully crowned Rollers p = 4.3. For an aerospace profile and chamfered Rollers, p = 4.6. Using the 1952 Lundberg-Palmgren value p = 10/3, the value incorporated in ANSI/ABMA and ISO bearing standards, can create significant life calculation errors for Roller Bearings
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Interference-Fit Life Factors for Roller Bearings
2009Co-Authors: Zaretsky Erwin, Oswald, Fred B., Poplawski JosephAbstract:The effect of hoop stresses in reducing Cylindrical Roller bearing fatigue life was determined for various classes of inner-ring interference fit. Calculations were performed for up to 7 fit classes for each of 10 bearing sizes. The hoop stresses were superimposed on the Hertzian principal stresses created by the applied radial load to calculate Roller bearing fatigue life. A method was developed through a series of equations to calculate the life reduction for Cylindrical Roller Bearings. All calculated lives are for zero initial internal clearance. Any reduction in bearing clearance due to interference fit would be compensated by increasing the initial (unmounted) clearance. Results are presented as tables and charts of life factors for Bearings with light, moderate, and heavy loads and interference fits ranging from extremely light to extremely heavy for bearing accuracy class RBEC-5 (ISO class 5). Interference fits on the inner ring of a Cylindrical Roller bearing can significantly reduce bearing fatigue life. In general, life factors are smaller (lower life) for Bearings running under light load where the unfactored life is highest. The various bearing series within a particular bore size had almost identical interference-fit life factors for a particular fit. The tightest fit at the high end of the tolerance band produces a life factor of approximately 0.40 for an inner-race maximum Hertz stress of 1200 MPa (175 ksi) and a life factor of 0.60 for an inner-race maximum Hertz stress of 2200 MPa (320 ksi). Interference fits also impact the maximum Hertz stress-life relation
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Interference Fit Life Factors for Roller Bearings
2008Co-Authors: Poplawski Joseph, Zaretsky Erwin, Oswald, Fred B.Abstract:The effect of hoop stresses in reducing Cylindrical Roller bearing fatigue life was determined for various classes of inner ring interference fit. Calculations were performed for up to seven interference fit classes for each of ten bearing sizes. Each fit was taken at tightest, average and loosest values within the fit class for RBEC-5 tolerance, thus requiring 486 separate analyses. The hoop stresses were superimposed on the Hertzian principal stresses created by the applied radial load to calculate Roller bearing fatigue life. The method was developed through a series of equations to calculate the life reduction for Cylindrical Roller Bearings based on interference fit. All calculated lives are for zero initial bearing internal clearance. Any reduction in bearing clearance due to interference fit was compensated by increasing the initial (unmounted) clearance. Results are presented as tables and charts of life factors for Bearings with light, moderate and heavy loads and interference fits ranging from extremely light to extremely heavy and for bearing accuracy class RBEC 5 (ISO class 5). Interference fits on the inner bearing ring of a Cylindrical Roller bearing can significantly reduce bearing fatigue life. In general, life factors are smaller (lower life) for Bearings running under light load where the unfactored life is highest. The various bearing series within a particular bore size had almost identical interference fit life factors for a particular fit. The tightest fit at the high end of the RBEC-5 tolerance band defined in ANSI/ABMA shaft fit tables produces a life factor of approximately 0.40 for an inner-race maximum Hertz stress of 1200 MPa (175 ksi) and a life factor of 0.60 for an inner-race maximum Hertz stress of 2200 MPa (320 ksi). Interference fits also impact the maximum Hertz stress-life relation
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Effect of Silicon Nitride Balls and Rollers on Rolling Bearing Life
2005Co-Authors: Vlcek, Brian L., Zaretsky Erwin, Hendricks, Robert C.Abstract:Three decades have passed since the introduction of silicon nitride Rollers and balls into conventional rolling-element Bearings. For a given applied load, the contact (Hertz) stress in a hybrid bearing will be higher than an all-steel rolling-element bearing. The silicon nitride rolling-element life as well as the lives of the steel races were used to determine the resultant bearing life of both hybrid and all-steel Bearings. Life factors were determined and reported for hybrid Bearings. Under nominal operating speeds, the resultant calculated lives of the deep-groove, angular-contact, and Cylindrical Roller hybrid Bearings with races made of post-1960 bearing steel increased by factors of 3.7, 3.2, and 5.5, respectively, from those calculated using the Lundberg-Palmgren equations. An all-steel bearing under the same load will have a longer life than the equivalent hybrid bearing under the same conditions. Under these conditions, hybrid Bearings are predicted to have a lower fatigue life than all-steel Bearings by 58 percent for deep-groove Bearings, 41 percent for angular-contact Bearings, and 28 percent for Cylindrical Roller Bearings
