Article
Engineering, Mechanical
Guoqing Xiong, Zhiwei Mao, Jinjie Zhang, Zijia Wang, Huailei Wang, Zhinong Jiang
Summary: Numerous studies have shown that both journal misalignment and bearing elastic deformation significantly affect lubrication performance. Recent research indicates that viscoelastic deformation is more useful than elastic deformation for determining the effects of strong impact loads. However, there have been no studies on the coupled effects of misalignment and viscoelastic deformation. Therefore, this study proposes a novel transient lubrication model that considers the influences of both misalignment and viscoelastic deformation, and investigates their coupled effects on lubrication performance.
INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES
(2023)
Article
Engineering, Mechanical
J. Y. Jang, M. M. Khonsari
Summary: The effect of aerated oil with air bubbles on journal bearings under steady and dynamic loads was investigated using thermohydrodynamic lubrication theory. The Reynolds equation was solved by employing a mass conservation algorithm, and the two-dimensional temperature field equations for both oil and solids were simultaneously solved. The simulations showed that the presence of air bubbles in the lubricating oil had a small effect on the pressure and temperature fields at normal operating speeds, but noticeably reduced density and effective viscosity.
TRIBOLOGY INTERNATIONAL
(2022)
Article
Engineering, Mechanical
S. Boedo
Summary: This paper introduces a computationally efficient implementation of a generalized short bearing (GSB) formulation using finite element method, which takes into account the mass conservation in cavitated bearing regions. The results demonstrate that the GSB formulation captures the bearing performance trends well when compared to a complete two-dimensional formulation and experimental results. Moreover, the GSB formulation achieves a computational speed approximately 40 to 200 times faster than the complete formulation for the given examples.
JOURNAL OF TRIBOLOGY-TRANSACTIONS OF THE ASME
(2022)
Article
Engineering, Mechanical
Jiaojiao Ma, Chao Fu, Weidong Zhu, Kuan Lu, Yongfeng Yang
Summary: This study analyzes the stochastic lubrications of a cylindrical hydrodynamic journal bearing with misalignment under uncertainties using the polynomial chaos expansion (PCE) and finite difference method. Various critical lubrication performance parameters are comprehensively studied by ensemble mean, standard deviation, probability density function, and cumulative distribution function. The findings provide insights into the significant effects of misalignment and different stochastic parameters on lubrication performance, guiding the robust design and analysis of general hydrodynamic journal bearings.
JOURNAL OF TRIBOLOGY-TRANSACTIONS OF THE ASME
(2022)
Article
Engineering, Mechanical
Amandine Regis, Jean-Marc Linares, Santiago Arroyave-Tobon, Emmanuel Mermoz
Summary: This study investigates the wear of plain bearings subjected to off-centred dynamic loads in order to improve their service life in severe aeronautic conditions. Experimental determination of wear coefficients for running-in and stable wear stages, along with validation of the evolution over time of maximum wear depth and contact zone size, were conducted.
Article
Engineering, Mechanical
Shaoyu Zhu, Xiangjun Zhang, Jun Sun, Dagang Wang
Summary: In this study, the static behavior of misaligned journal bearings under heavy loads was investigated using a non-Newtonian lubricant (pseudoplastic fluid with power-law relationship). The generalized average Reynolds equation for rough journal bearing under pseudoplastic lubricant flow was derived, using the average flow method of Patir and Cheng for model equation establishment. The numerical solution of bearing performance parameters was obtained using the finite difference method and the successive over-relaxation method, and it was found that surface roughness could partially compensate for the effects of liner elastic deformation and lubricant shear thinning. The derived generalized average Reynolds equation can be applied not only in the research of hydrodynamic lubrication but also in the research of mixed lubrication.
TRIBOLOGY INTERNATIONAL
(2023)
Article
Engineering, Mechanical
S. Boedo
Summary: This study investigates the impact of surface ellipticity on self-acting partial arc journal bearings under steady load and sinusoidal oscillation, taking into account mass conserving cavitation. The computational efficiency is improved by using a generalized Warner bearing (GWB) formula. The results demonstrate that an elliptical sleeve can significantly improve bearing performance at small oscillation amplitudes commonly found in practical applications, and a fully hydrodynamic lubrication regime can be established through the wearing-in process of the sleeve surface.
TRIBOLOGY INTERNATIONAL
(2022)
Article
Engineering, Mechanical
C. A. Lindley, S. Beamish, R. S. Dwyer-Joyce, N. Dervilis, K. Worden
Summary: This study proposes a probabilistic framework based on Gaussian Processes to model the oil film thickness, and uses likelihood maps to estimate the location of the bearing shaft, thereby improving the confidence of the predictions.
MECHANICAL SYSTEMS AND SIGNAL PROCESSING
(2022)
Article
Engineering, Mechanical
Shengbo Li, Alexander Babin, Denis Shutin, Yuri Kazakov, Yifan Liu, Zhaobo Chen, Leonid Savin
Summary: This study proposes an approach for designing rotating machines with water lubricated active hybrid journal bearings. The adjustable lubricant supply pressure in the bearing influences the journal position, and a machine learning based model predictive controller is used to reduce energy consumption.
TRIBOLOGY INTERNATIONAL
(2022)
Article
Engineering, Mechanical
Bassam J. Alshaer, Hamid M. Lankarani
Summary: A new solution for the dynamic characteristics of lubricated long journal bearing is derived by analytically integrating Reynold's equation. The solution does not involve approximations or assumptions and presents new equations to evaluate lubricant dynamic forces and zero pressure angles. The squeeze and dynamic effects are uncoupled, making it easier to study their contributions to total lubricant forces.
MECHANISM AND MACHINE THEORY
(2023)
Article
Engineering, Mechanical
Wanjun Xu, Shanhui Zhao, Yaoyao Xu, Kang Li
Summary: The study compared the effects of cavitation on various performance parameters of journal bearings, showing that a decrease in cavitation pressure improves load-carrying capacity, especially in lightly loaded cavitated bearings. The difference between the Reynolds model and the JFO theory can generally be ignored in non-cavitated cases and cavitated cases with intermediate to heavy loads, but the accuracy of leakage prediction using the Reynolds model should be carefully evaluated.
Article
Engineering, Electrical & Electronic
Marcus Gaertner, Christian Brecher, Stephan Neus, Hans-Martin Eckel, Andreas Bartelt, Maik Hoppert, Mohammad Reza Ilkhani
Summary: Friction losses are important for evaluating the behavior of high-speed rolling bearings, particularly in machine tool applications where high radial loads and speeds increase forces and friction. Hybrid spindle bearings, made of ceramic balls and steel raceways, demonstrate better friction behavior compared to full steel bearings. Accurate understanding of the friction characteristics of high-speed hybrid bearings can improve friction models for different types of spindle bearings. This article presents a cost-efficient method for measuring friction torque in spindle bearings and discusses the effects of lubrication. A friction calculation model is also proposed and validated based on test results to control outer race and minimize power dissipation.
Article
Chemistry, Multidisciplinary
Syed Muntazir Mehdi, Tae Ho Kim
Summary: This study develops a computational model for analyzing tilting pad journal bearings lubricated with supercritical carbon dioxide (sCO(2)). The model successfully predicts the pressure distribution, static equilibrium position, and temperature distribution of the bearings using numerical methods such as the Reynolds equation, Newton-Raphson method, and finite difference method. The results show that hybrid lubrication significantly improves the load capacity of the bearings, and increasing the supply pressure of sCO(2) further enhances the bearing performance.
APPLIED SCIENCES-BASEL
(2022)
Article
Engineering, Mechanical
Hasan Bas, Yunus Emre Karabacak
Summary: In this research, machine learning algorithms were used to predict the variations of friction torque and friction coefficient in a statically loaded radial journal bearing. The effects of temperature, bearing load, and rotational speed on these variations were investigated. The results showed that machine learning models can successfully predict the variations of friction torque and friction coefficient. Additionally, a comparative analysis was conducted to evaluate the performance of different machine learning models. These findings have important implications for the design and optimization of statically loaded radial journal bearings.
TRIBOLOGY INTERNATIONAL
(2023)
Article
Engineering, Mechanical
S. Beamish, R. S. Dwyer-Joyce
Summary: This article presents the design of a journal bearing test platform that utilizes ultrasonic transducers for high-accuracy film thickness measurements. The platform is capable of simulating loading patterns found in real components and allows detailed analysis of the film thickness response to rapidly changing loads. The results demonstrate the advantages of the ultrasonic technique in studying phenomena at the shaft-bearing interface and the successful implementation of the snapshot technique for measurements.
TRIBOLOGY TRANSACTIONS
(2022)
