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
Mohammad Tauviqirrahman, J. Jamari, Arjuno Aryo Wicaksono, M. Muchammad, S. Susilowati, Yustina Ngatilah, Caecilia Pujiastuti
Summary: In this study, a computational investigation into the acoustic and tribological performances in journal bearings is presented, using a heterogeneous pattern with rough surfaces engineered in certain regions. Numerical results show that heterogeneous rough/smooth bearings can provide lower noise and larger load-carrying capacity compared to conventional bearings, with discussions on the effects on friction force.
Article
Engineering, Mechanical
Dov Avishai, Groper Morel
Summary: This study examines the application of water-lubricated bearings in the propulsion systems of naval vessels, analyzing their lubrication status through experimentation and modeling. The goal is to reduce environmental pollution risks and improve the operational performance of ships.
JOURNAL OF TRIBOLOGY-TRANSACTIONS OF THE ASME
(2021)
Article
Engineering, Electrical & Electronic
Gwanghee Hong, Kyobong Kim, Youngjun Park, Gunhee Jang
Summary: This paper proposes a numerical method to investigate the frictional characteristics of a fluid film journal bearing considering the elastohydrodynamic lubrication and the asperity contact force. The method is verified by comparing the calculated friction coefficient with experimental data, and it is applied to study the frictional characteristics of a scroll compressor journal bearing under dynamic loads.
Review
Engineering, Mechanical
Sitae Kim, Dongil Shin, Alan B. Palazzolo
Summary: This review summarizes the effects of nonlinear elements in fluid film journal bearings on rotor-bearing systems, including sub- and super-synchronous, chaos and thermally induced instability responses. It also discusses the importance of nonlinear, thermo-elasto-hydrodynamic aspects of journal bearings in high-performance turbomachines, and presents nonlinear solution methodologies and numerical tools for analyzing nonlinear vibration responses induced by bearings.
JOURNAL OF TRIBOLOGY-TRANSACTIONS OF THE ASME
(2021)
Article
Engineering, Mechanical
G. Martin, Florian Michael Becke, E. Kirchner
Summary: This paper presents a novel condition monitoring method for rolling bearings based on measuring the electric bearing impedance. The method can diagnose damage presence through frequency-domain analysis and assess the severity and progression of bearing damage through time-domain analysis.
TRIBOLOGY INTERNATIONAL
(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
Dongil Shin, Alan B. Palazzolo
Summary: This study investigates the influence of misaligned journal bearing on thermally induced rotor instability, using a three-dimensional finite element model for simulations. Results indicate that the amplitude of misalignment angle affects the instability speed range.
JOURNAL OF TRIBOLOGY-TRANSACTIONS OF THE ASME
(2021)
Article
Engineering, Mechanical
Nathan Hess, Lizhi Shang
Summary: This study introduces a machine learning neural network model that can approximate pressure distribution at steady state. Through data generation and hyperparameter optimization, the neural network shows good prediction capability, accurately estimating journal bearing loads, demonstrating the feasibility of applying machine learning to fluid power pump and motor simulation models.
JOURNAL OF TRIBOLOGY-TRANSACTIONS OF THE ASME
(2022)
Article
Engineering, Mechanical
Jacopo Tacconi, Shahrokh Shahpar, Andrew King, Johannes Paulus Olufeagba, Raymarn Khan, Ian Sant, Martin Yates
Summary: Gear pumps are widely used in aero-engine fuel systems, and the design and analysis of hybrid journal bearings used in these pumps pose challenges. A numerical model has been developed to evaluate and design the pressure distribution of hybrid journal bearings for fuel pump applications. The tool has been validated and shows good accuracy and robustness.
JOURNAL OF TRIBOLOGY-TRANSACTIONS OF THE ASME
(2022)
Article
Engineering, Mechanical
Kushagra Singh, Farshid Sadeghi, Wyatt Peterson, Steven J. Lorenz, Jaret Villarreal, Takumi Jinmon
Summary: This paper presents a partitioned, two-dimensional fluid structure interaction (FSI) model to investigate the effects of surface cracks in rolling/sliding line contacts under elastohydrodynamic lubrication (EHL). The FSI model is capable of modeling surface cracks with inclined geometries, capturing the pressure distribution, fluid streamlines, and stress concentration in the solid simultaneously. The model results can provide accurate boundary conditions for crack propagation modeling and identify the crack geometries that affect fatigue life in EHL contact.
TRIBOLOGY INTERNATIONAL
(2022)
Review
Engineering, Mechanical
Dongil Shin, Jongin Yang, Xiaomeng Tong, Junho Suh, Alan Palazzolo
Summary: This paper provides an extensive survey of thermal modeling methods and effects in journal bearings, covering a wide range from conventional Reynolds equation models to advanced computational fluid dynamics models. Thermal effects in journal bearings play a critical role in both static and dynamic properties, influencing rotor-bearing system performance. Various bearing types and recent progress in thermal design and thermal instability problems in fluid and gas film hydrodynamic bearings are also discussed in the paper.
JOURNAL OF TRIBOLOGY-TRANSACTIONS OF THE ASME
(2021)
Article
Computer Science, Interdisciplinary Applications
Wonvin Kim, Su Hyun Lim, Hyunsoo Hong, Kwang Il Jeong, Seung Yoon On, Seong Yeon Park, Jun Il You, Seong Su Kim
Summary: This study analyzed the effects of turbulence, inertial effect, and elastic deformation on a water-lubricated composite journal bearing system. The Reynolds equation and constitutive equation were modified and solved using the finite difference method and finite element method, respectively. The normalized minimum film thickness was modeled based on the Gaussian regression model, and new optimal maximum load-carrying capacity boundaries were proposed.
JOURNAL OF COMPUTATIONAL DESIGN AND ENGINEERING
(2022)
Article
Acoustics
H. A. P. Silva, R. Nicoletti
Summary: Rotating machines are crucial to the production chain, but their off-the-norm operation can lead to failure and economic losses. Active bearings can modify the dynamic characteristics of the machines without requiring stops, reducing the consequences of off-the-norm operation. This study presents a tilting-pad journal bearing with electromagnetic actuators, demonstrating its effectiveness in reducing lateral vibrations of the rotor during operation.
JOURNAL OF SOUND AND VIBRATION
(2023)
Article
Engineering, Chemical
Michal Michalec, Martin Ondra, Martin Svoboda, Jiri Chmelik, Petr Zeman, Petr Svoboda, Robert L. Jackson
Summary: This study proposes a new two-parameter method using Computational Fluid Dynamics (CFD) to estimate the optimal proportions of a hydrostatic bearing pad. The method considers the recess area and position, and was found to reduce energetic loss by 20% compared to the traditional one-parameter approach. The results demonstrate the versatility and effectiveness of this methodology in designing optimal hydrostatic bearings with minimum energetic loss in low-speed conditions.