The Experts below are selected from a list of 186 Experts worldwide ranked by ideXlab platform
A Choudhury - One of the best experts on this subject based on the ideXlab platform.
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vibration response of rolling element bearings in a rotor bearing system to a local defect under Radial Load
Journal of Tribology-transactions of The Asme, 2006Co-Authors: A Choudhury, N TandonAbstract:In the present investigation, a theoretical model has been developed to obtain the vibration response due to a localized defect in various bearing elements in a rotor-bearing system under Radial Load conditions. The rotor-bearing system has been modeled as a three degrees-of-freedom system. The model predicts significant components at the harmonics of characteristic defect frequency for a defect on the particular bearing element. In the case of a defect on the inner race or a rolling element, the model predicts sidebands about the peaks at defect frequencies, at multiples of shaft and cage frequencies, respectively. The model has also predicted some additional components at harmonics of shaft and cage frequencies due to a local defect on the inner race and a rolling element, respectively. The expressions for all these spectral components have also been derived. Typical numerical results for an NJ 204 bearing have been obtained and plotted. The amplitude of the component at defect frequency, for an outer race defect, is found to be much higher as compared to those due to inner race defect or a rolling element defect of the same size and under similar conditions of Load and speed. The results of vibration measurements on roller bearings with simulated local defects have also been presented to experimentally validate the theoretical model proposed. It can be observed from the results that the spectral components predicted by the theoretical model find significant presence in the experimental spectra. Comparison of the normalized analytical values of the spectral components with their experimental values shows fair agreement for most of the cases considered. Probable area of the generated excitation pulses has been calculated and the effects of pulse area variation on the experimental results have been studied.
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a theoretical model to predict the vibration response of rolling bearings in a rotor bearing system to distributed defects under Radial Load
Journal of Tribology-transactions of The Asme, 2000Co-Authors: N Tando, A ChoudhuryAbstract:A theoretical model to predict the vibration response of rolling element bearing in a rotor bearing system to distributed defects under Radial Load has been developed. The rotor bearing system has been considered as a three degrees of freedom model. The distributed defects considered are, the waviness of outer and inner races, and off size rolling element. The model predicts discrete spectrum with specific frequency components for each order of waviness. For outer race waviness, the spectrum has components at outer race defect frequency and its harmonics. In the case of inner race waviness, the waviness orders equal to number of rolling elements and its multiples give rise to spectral components at inner race defect frequency and its multiples. Other orders of waviness generate sidebands at multiples of shaft frequency about these peaks. The model predicts the amplitudes of the spectral components due to outer race waviness to be much higher as compared to those due to inner race waviness. In the case of an off-size rolling element, the model predicts discrete spectra having significant components at multiples of cage frequency.
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a theoretical model to predict vibration response of rolling bearings to distributed defects under Radial Load
Journal of Vibration and Acoustics, 1998Co-Authors: A Choudhury, N TandoAbstract:An analytical model has been presented to predict the vibration response of rolling bearings due to distributed defects under Radial Load. For bearings without defect and with race defect, the model predicts a discrete spectrum with components at outer and inner race characteristic defect frequencies for the response of the respective races. The amplitude level for race defect significantly increases at the respective frequencies in comparison to the response ofa bearing without defect. For a bearing with off-size rolling element, the response is at the relative frequency of cage with respect to the frequency of motion of the corresponding race.
Seongwook Hong - One of the best experts on this subject based on the ideXlab platform.
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skidding analysis of angular contact ball bearing subjected to Radial Load and angular misalignment
Journal of Mechanical Science and Technology, 2019Co-Authors: Laily Oktaviana, Vancanh Tong, Seongwook HongAbstract:Skidding is a phenomenon that frequently occurs in ball–raceway contact areas of bearings and often leads to their early failure. This paper presents a skidding analysis of angular contact ball bearings (ACBBs) subjected to various boundary conditions. A five degrees-offreedom quasi-static model for ACBBs was employed to investigate skidding with ball and race contact forces and inertial Loading by rotational speed. The model provided the internal Load distribution of all rolling elements, which was subsequently used for the skidding prediction. Hirano’s criterion was used as a theoretical basis for the skidding analysis of ACBBs. Simulations were performed to investigate the influence of external Loading, rotational speed, and angular misalignment on the bearing skidding. The effects of the preLoad method and initial contact angle on the skidding were also considered. As a result, this study provided an in-depth observation of skidding in ACBBs subjected to various operating conditions.
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fatigue life analysis for angular contact ball bearing with angular misalignment
Journal of the Korean Society for Precision Engineering, 2016Co-Authors: Vancanh Tong, Seongwook HongAbstract:Angular misalignment has a significant effect on the characteristics of angular contact ball bearings (ACBBs). This paper presents an analysis of fatigue life for ACBBs subjected to angular misalignment. A simulation model is developed with de Mul’s bearing model and the ISO basic reference rating life model. Simulation is performed to calculate the life of the ACBBs subjected to angular misalignment. The numerical results show that angular misalignment influences the Load distribution significantly, thus reducing the bearing rating life. The fatigue life of ACBBs is decreased by angular misalignment regardless of axial preLoad, external Radial Load and rotational speed. The results show that angular misalignment should be maintained at less than 1mrad for ACBBs.
Yimin Shao - One of the best experts on this subject based on the ideXlab platform.
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an analytical model to predict vibrations of a cylindrical roller bearing with a localized surface defect
Nonlinear Dynamics, 2017Co-Authors: Yimin ShaoAbstract:The main failure mode of cylindrical roller bearings (CROBs) is localized surface defects (LSDs) such as spalls and pits on the surface of its races or rollers. However, it is difficult to describe the time-varying deflection excitation (TVDE) generated by a LSD and time-varying contact stiffness excitation due to the changes in contact conditions between the roller and defect by using the previous defect models. In this paper, a new dynamic analysis method is proposed to formulate a LSD more accurately for a CROB dynamic modeling. A two-degree of freedom dynamic model for a CROB with a LSD on its races is proposed, which considers both the TVDE and time-varying contact stiffness coefficient produced by the defect. The Load-deflection relationship between the roller and race is considered as non-Hertzian one, which can be used to determine the Load-deflection relationship between the logarithmic-profile roller and races of the CROB. The numerical results are compared with the available results from the previous defect models in the literature. Effects of the Radial Load, defect sizes and types on the contact deformation and contact force between the roller and race are investigated, as well as the vibrations characteristics of the CROB. The results show that the proposed method can describe more accurately a real excitation produced by a LSD located at anywhere in the contact zone between the roller and race, which cannot be captured by the previous model in the literature.
Kenji Kanemasu - One of the best experts on this subject based on the ideXlab platform.
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influence of Radial Load on peek plastic bearings life cycle under water lubricated conditions
Advanced Materials Research, 2011Co-Authors: Hitonobu Koike, Takashi Honda, Katsuyuki Kida, Edson Costa Santos, Yuji Kashima, Justyna Rozwadowska, K Houri, Megumi Uryu, Kenji KanemasuAbstract:Radial ball bearings made of metal, ceramics and plastics are commonly used as important components in industrial machinery. Usage of high performance engineering plastic polymers is increasing progressively as a replacement for metal components due to the latest markets demands. Poly-ether-ether-ketone (PEEK) is a promising material for precision-machined custom bearings, products that are expected to suit special market needs. In the present study, PEEK Radial ball bearings were manufactured by lathe machining under different parameters and their rolling contact fatigue (RCF) resistance under water lubricated conditions was investigated. We observed the surface of the bearings prior and after testing by laser confocal microscope. The wear loss was measured by weighing the bearings before and after test. Cracks and/or flaking failures were identified on the bearing surface after testing. From the RCF tests results, we found that, at water lubricated conditions, crack initiation occurred later in the material that was machined at slower feed rate while at dry condition, the feed rate had little influence on the wear loss and cracking. Wear loss in the case of bearings tested under water was much less severe than that of bearings tested at dry conditions.
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influence of Radial Load on peek plastic bearings life cycle
Advanced Materials Research, 2010Co-Authors: Hitonobu Koike, Takashi Honda, Katsuyuki Kida, Edson Costa Santos, Yuji Kashima, Kenji KanemasuAbstract:Nowadays, due to strict environmental requirements, the automotive industry has been reducing vehicle weight in order to minimize the CO2 emission. This had led to an increase in the demand for plastic car parts as a replacement for formerly metal components. Poly ether-ether-ketone (PEEK) has a high glass transition temperature of 143°C, good friction and heat resistance, and can be easily machined. Due to these characteristics, PEEK is already being widely applied in the production of various car parts, such as seat adjustment parts, transmission parts, oil-pump parts etc. In the present study, PEEK bearings were produced by machining and their rolling contact fatigue (RCF) under non-lubricated conditions was investigated. Under high Radial Load, seizure in the inner bearing part occurred while under low Radial Load, there was failure by adhesive wear. Exposed to medium Load between 85.6N and 93.1N, however, the bearings achieved relatively long lives of over 1.0x10E6 cycles, as well as a unique feature of self-lubrication that rid the raceway of micro depressions, deposits or smearing.
Zhai Jia - One of the best experts on this subject based on the ideXlab platform.
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calculation of Radial Load distribution on ball and roller bearings with positive negative and zero clearance
International Journal of Mechanical Sciences, 2017Co-Authors: Re Xiaoli, Zhai JiaAbstract:Abstract The Load distribution on rolling elements is one of the most important operating characteristics of a bearing. In this paper, a mathematical model for the calculation of Radial Load distribution on ball and roller bearings with positive, negative and zero clearance is derived and presented. A predeformation model for bearings with nonzero clearance is proposed. Based on contact deformation and Hertz elastic contact theory, inner raceway contact force is calculated and is used for static equilibrium equation, which could avoid calculate the series of stiffness of inner and outer raceway contact deformation. The static equilibrium equation is solved by a loop which aims to delete inactive rolling elements. The obtained results are compared with results of Harris and Stribeck method and found to be in close or identical agreement.
