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
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
Juan Guo, Guo Xiang, Jiaxu Wang, Yankui Song, Jianlin Gai, Haiming Dai
Summary: This paper introduces a method of one-side profile modification for reducing the edge wear caused by journal defection in misaligned journal bearings. The effectiveness of the modification is confirmed through numerical calculations. The results indicate that the reasonable design of one-sided profile modification can increase the minimum film thickness at the edge of the bearing and reduce rough contact, thus improving the anti-wear performance of the misaligned journal bearing.
SURFACE TOPOGRAPHY-METROLOGY AND PROPERTIES
(2022)
Article
Engineering, Mechanical
Chunjie Wei, Guiwen Liao, Wei Wang, Jimin Xu, Kun Liu
Summary: In this study, the transient tribo-dynamics and wear model were coupled to investigate the mixed lubrication-wear behavior during start-up. The numerical model considered the film thickness equation with wear depth and a time-varying wear coefficient. Results showed that wear behavior had a significant impact on the evaluation of the bearing-rotor system's start-up performance and even influenced the determination of optimal parameters. Additionally, the study revealed that external load and lubricant viscosity greatly influenced wear and mixed lubrication performance.
PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART J-JOURNAL OF ENGINEERING TRIBOLOGY
(2023)
Article
Engineering, Mechanical
Guo Xiang, Yanfeng Han, Jiaxu Wang, Ke Xiao, Junyang Li
Summary: This study investigates the transient hydrodynamic coupling mechanism of misaligned journal-thrust microgrooved coupled bearings under water lubrication, finding that axial microvibration affects the load capacity of the coupled bearing and that negative misalignment mode improves load capacity.
TRIBOLOGY TRANSACTIONS
(2021)
Article
Engineering, Marine
Weixin Zhou, Yao Zhao, Hua Yuan, Jingxi Liu, Xiaoqiang Wang
Summary: This paper uses the influence coefficient factors method to analyze the contact pressure of misaligned bearings. The results show that the influence coefficient factors are greatly affected by the shape and constraints of the contact object. The proposed method is suitable for cylindrical shell contact analysis and has the same accuracy as FEM with half of the time consumption.
JOURNAL OF MARINE SCIENCE AND ENGINEERING
(2022)
Article
Engineering, Mechanical
Kang Yan, Hulin Li, Ning Ding, Dan Jiang, Xianghui Meng
Summary: This study establishes a transient-mixed lubrication model to predict the performance of journal bearings under heavy load during start-up, with a focus on friction and wear behavior. The results show the importance of reasonable start-up acceleration and setting linear wear times for accurate performance prediction. The wear mainly spreads in the clearance direction during the start-up process, affecting the friction performance.
INDUSTRIAL LUBRICATION AND TRIBOLOGY
(2022)
Article
Engineering, Mechanical
Ebrahim Tofighi-Niaki, Mir Saeed Safizadeh
Summary: This paper investigates the effects of wear-induced geometric imperfections of tilting pad journal bearings (TPJBs) on the dynamic behavior of the system. A novel tribo-dynamic model is proposed for a flexible rotor-worn TPJB to assess the effects of bearing wear progression on rotor-TPJB behavior. Results show that wear changes the temperature distribution of the pads and oil film as well as the dynamic behavior of the system. Wear TPJBs exhibit higher vibration levels and contact pressures near the system's critical speed and service speed. Thermal and dynamic condition indicators are suggested to detect TPJB wear severity at its early stages.
Article
Engineering, Mechanical
Woo-Ju Jeon, Sung-Ho Hong
Summary: A flexible structure is used to enhance the lubrication performance of a misaligned journal bearing. The bearing, which represents a sliding bearing, suffers damage from metal-to-metal contact caused by misalignment. To improve this issue, a journal bearing with a flexible structure is proposed. Numerical evaluation and elastohydrodynamic lubrication analysis considering elastic deformation are conducted, comparing lubrication performance based on variations in the flexible structure's geometry and minimum film thickness. Comparisons are also made between the journal bearing with and without the flexible structure. The flexible structure, in the form of a groove, is applied to the high load-bearing area of the journal bearing, experiencing elastic deformation through the generated oil film pressure to obscure a larger oil film. The numerical analysis demonstrates that the journal bearing with a flexible structure can enhance lubrication performance in misalignment conditions.
Article
Engineering, Mechanical
Ning Ding, Shebin Yan, Gaozhang Ma, Hulin Li, Dan Jiang
Summary: This paper proposes an adaptive iterative method based on a mixed thermo-elasto-hydrodynamic (TEHD) lubrication and wear coupling model to investigate the lubrication and wear behaviors of journal bearings in the mixed lubrication. The evolution laws of the oil film thickness, the hydrodynamic pressure, the asperity contact pressure, the friction power loss, and the wear distribution are discussed and compared under different running times, oil temperatures, external loads, and shaft rotational speeds. The three-dimensional surface models based on the asperity contact power loss and the maximum wear depth with the variation of the running time and the oil temperature are fitted under specific external loads and shaft rotational speeds.
PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART C-JOURNAL OF MECHANICAL ENGINEERING SCIENCE
(2023)
Article
Engineering, Mechanical
Ozhan Gecgel, Joao Paulo Dias, Stephen Ekwaro-Osire, Diogo Stuani Alves, Tiago Henrique Machado, Gregory Bregion Daniel, Helio Fiori de Castro, Katia Lucchesi Cavalca
Summary: A framework using a deep learning algorithm to classify wear faults in hydrodynamic journal bearings was proposed, showing promising results for early diagnosis of wear faults in rotating machinery.
JOURNAL OF TRIBOLOGY-TRANSACTIONS OF THE ASME
(2021)
Article
Mechanics
Priya Gajjal, G. S. Lathkar
Summary: This research aims to design an efficient bearing faults detection system to address the issue of long processing time and low accuracy of traditional techniques when dealing with large data. By optimizing the parameters in the modular neural frame and improving the adaptability of ant lion and African buffalo, the fault prediction accuracy has been enhanced. The proposed model, implemented in the MATLAB environment, has achieved the finest results in various indicators.
ARCHIVE OF APPLIED MECHANICS
(2022)
Article
Engineering, Electrical & Electronic
Guglielmo Giannetti, Enrico Meli, Andrea Rindi
Summary: Tilting pad journal bearings (TPJBs) are important components in modern rotating machines. This study proposes an innovative modeling approach based on efficient flexible multibody techniques to describe the behavior of TPJBs. The model is tested on a real TPJB geometry and validated through experimental tests, showing encouraging results. The proposed model can be applied in various engineering fields such as Oil & Gas and aeronautics.
Article
Engineering, Mechanical
Bin Wei, Yinghou Jiao, Xianglin Wu
Summary: The aim of this study is to present a technical numerical method to improve the efficiency of solving the Reynolds equation for hydrodynamic bearings. The developed method effectively combines the Bi-CGSTAB algorithm with the Reynolds boundary conditions to characterize the pressure distribution within the lubricant for hydrodynamic bearings.
JOURNAL OF TRIBOLOGY-TRANSACTIONS OF THE ASME
(2022)
Article
Engineering, Chemical
Zeyu Zhao, Qianwen Huang, Minghui Sheng
Summary: The marine stern bearing provides support by minimizing contact friction with the propeller shaft through a lubricating film. A model considering local wear and asperity contact is used to study the mixed lubrication of misaligned bearings. The finite difference method and over-relaxation iteration method are used to solve the average Reynolds equation and calculate lubrication behavior such as hydrodynamic pressure, film thickness, contact force, and friction coefficient. The effects of sliding speed, local wear, contact roughness, misalignment angle, elastic deformation, and eccentricity ratio are discussed, and the critical speed for transitioning from mixed to fluid lubrication is determined using the Stribeck curve. Moreover, the dimensionless average hydrodynamic pressure, film thickness, and peak value of contact force are compared.
LUBRICATION SCIENCE
(2023)
Article
Engineering, Mechanical
Haiming Dai, Guo Xiang, Jiaxu Wang, Juan Guo, Cheng Wang, Hang Jia
Summary: Numerical investigation was conducted on the time-varying mixed lubrication performance of microgroove journal-thrust coupled bearing (MJTCB) under nonlinear excitation. The study revealed that the coupling hydrodynamic effect on the mixed lubrication performance of the bearing was strengthened with increased microgroove depth. Moreover, the optimal microgroove shape for the thrust bearing depended significantly on the microgroove depth. The contact performance of the thrust bearing was slightly influenced by the radial external load.
INDUSTRIAL LUBRICATION AND TRIBOLOGY
(2022)
Article
Engineering, Mechanical
Guo Xiang, Jiaxu Wang, Yanfeng Han, Tianyou Yang, Haiming Dai, Bowen Yao, Chuande Zhou, Liwu Wang
Summary: This study investigates the transient nonlinear dynamic behaviors of water-lubricated bearings with unbalanced rotors under mixed-TEHD condition. The thermal effect and friction force are found to play an important role in the nonlinear dynamic analysis. The perturbed method may lead to inaccurate predictions of transient hydrodynamic and contact forces, especially for the contact force, under mixed-TEHD condition. Parametric studies highlight the key factors for improving transient lubrication performance.
MECHANICAL SYSTEMS AND SIGNAL PROCESSING
(2022)
Article
Engineering, Mechanical
Shouan Chen, Guo Xiang, Michel Fillon, Juan Guo, Jiaxu Wang, Jianlin Cai
Summary: This paper investigates the impact of imperfect journal on the tribo-dynamic behavior of water-lubricated bearings during start-up. The numerical model shows that the shape error of the journal can affect the performance of the bearing, but within a reasonable range, it can also improve the tribological performance.
TRIBOLOGY INTERNATIONAL
(2022)
Article
Metallurgy & Metallurgical Engineering
Dong-xing Tang, Lei Yin, Bin Xiao, Yan-feng Han, Guo Xiang, Jia-xu Wang
Summary: The present study aims to establish a mixed lubrication model for coupled bearings used in ship shaftless rim-driven thrusters. Based on numerical results, the optimal bottom shape and tilting angle of the bearing have been determined, with the coupled bearing having a left triangle microgroove bottom shape exhibiting the best lubrication performance.
JOURNAL OF CENTRAL SOUTH UNIVERSITY
(2022)
Article
Engineering, Mechanical
Guo Xiang, Tianyou Yang, Juan Guo, Jiaxu Wang, Bin Liu, Shouan Chen
Summary: A surface profile modification method is proposed to improve the WAC performance of water-lubricated bearings under fluid-solid-thermal coupling condition. Numerical calculations demonstrate the effectiveness of the method in decreasing wear depth and asperity contact force. The optimal modification width and depth are determined, and parametric studies reveal the method's effectiveness is closely related to design parameters and operating conditions. Generally, a large modification depth is not recommended.
Article
Engineering, Mechanical
Jianlin Cai, Yanfeng Han, Guo Xiang, Cheng Wang, Liwu Wang, Shouan Chen
Summary: This study investigates the role of mass conservation boundary on the tribo-dynamic responses of micro-groove water-lubricated bearings under mixed lubrication. The simulation results show that cavitation can stabilize the bearing's movement and enhance the dynamic pressure effect of the micro-grooves. The analysis of rotational speed and micro-groove depth parameters confirms their significant influence on the cavitation zone and dynamic pressure effect of the bearings.
SURFACE TOPOGRAPHY-METROLOGY AND PROPERTIES
(2022)
Article
Engineering, Mechanical
Lei Cao, Jianlin Cai, Cheng Wang, Tianyou Yang, Wei Zhou, Liwu Wang
Summary: The purpose of this study is to investigate the influence of boundary slip associated with an arbitrary entrainment angle on the lubrication properties of ellipses. Numerical simulations based on the modified Reynolds equation are conducted, and the results show that the film thickness varies significantly with different entrainment angles when boundary slip is considered. Boundary slip reduces the central and minimum film thickness, resulting in a smoother hydrodynamic pressure distribution. This study provides insights into the elastohydrodynamic lubrication characteristics under arbitrary rolling and sliding velocities, which is important for understanding the lubrication behavior in various mechanical components.
INDUSTRIAL LUBRICATION AND TRIBOLOGY
(2023)
Article
Engineering, Mechanical
Tianyou Yang, Jianlin Cai, Liwu Wang, Dongxing Tang, Shouan Chen, Jiaxu Wang
Summary: The purpose of this study is to investigate the impact of turbulence on the lubrication performance of a coupled journal-thrust water-lubricated bearing with micro grooves. A numerical model is used to compare the results with published experimental data for validation. The study examines the variations in load capacity, maximum film pressure, and local Reynolds number with different operating conditions and micro groove depths.
JOURNAL OF TRIBOLOGY-TRANSACTIONS OF THE ASME
(2023)
Article
Engineering, Mechanical
Hengguan Zhang, Jianlin Cai, Tianyou Yang, Shouan Chen, Dongxing Tang, Jiaxu Wang
Summary: The study aims to investigate the impact of bearing waviness on the lubrication performances of coupled journal-thrust water-lubricated bearings using an elastohydrodynamic lubrication model. The numerical model is validated against published experimental data. The numerical model is used to calculate the load capacity and maximum fluid pressure under different parameters of bearing waviness, and then analyze the influence of bearing waviness on the performance of the bearings. Simulation results show that the waviness amplitude significantly affects the bearing performances, with a larger influence as the amplitude increases.
SURFACE TOPOGRAPHY-METROLOGY AND PROPERTIES
(2023)
Article
Engineering, Mechanical
Minsi Li, Guo Xiang, Roman Goltsberg
Summary: This paper presents a novel approach for simulating adhesive wear in elastic-plastic spherical contacts using an improved finite element sub-model. The proposed method includes a global model with a coarse mesh and a refined mesh sub-model. The expression derived in the study reveals the limited effect of sphere radius on wear rate and the influence of mechanical properties on wear particle morphology.
Article
Engineering, Mechanical
Bowen Yao, Guo Xiang, Jiaxu Wang, Juan Guo, Yanyu Nie
Summary: The role of wall slip on the transient hydrodynamic performance of water-lubricated bearings with eccentricity rotor is investigated in this study. The modified Reynolds equation with wall slip is used to calculate the transient hydrodynamic pressure, and a fully coupled motion equation is employed to determine the journal orbit. Numerical results verify the accuracy of the model and show that the unbalance load caused by the eccentricity rotor leads to variations in transient hydrodynamic properties, film thickness, and slip velocity. The positive effect of wall slip on the transient hydrodynamic performance is mainly dependent on the eccentricity ratio and the slip region has a greater impact on the maximum slip velocity compared to the minimum slip velocity. This study emphasizes the importance of wall slip in transient hydrodynamic performance and recommends an optimal wall slip region design for water-lubricated bearings under transient operating conditions.
INTERNATIONAL JOURNAL OF SURFACE SCIENCE AND ENGINEERING
(2023)
