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
Chemistry, Physical
Maria J. G. Guimarey, David E. P. Goncalves, Jose M. Lineira del Rio, Maria J. P. Comunas, Josefa Fernandez, Jorge H. O. Seabra
Summary: The lubricant properties of trimethylolpropane trioleate synthetic base oil were determined experimentally, showing that the addition of nanoparticles like graphene nanoplatelets can affect the performance of the base oil. Nanolubricants with graphene nanoplatelets at a concentration of 0.25wt% exhibited the lowest friction coefficient.
JOURNAL OF MOLECULAR LIQUIDS
(2021)
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
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, Chemical
Katrina Avery, Mackenzie Roach, Erdogan Kiran, John Hassler, Mark T. Devlin
Summary: This study investigates the impact of polyisobutylene (PIB) on the volumetric properties and viscosity of synthetic poly(alpha-olefin) base oil. Experimental evaluations were conducted to examine the effects of different molecular weights and addition levels of PIB on the base oil. Correlations between density and viscosity were analyzed to understand the changes caused by PIB. The results provide insights into the alterations in the base oil's packing and other parameters induced by PIB.
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
(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
W. Habchi, P. Sperka, S. Bair
Summary: Considering the glass transition is necessary for predicting the minimum film thickness in EHL traction analysis. Neglecting the impact of glass transition has concealed the role of vitrification in this process.
TRIBOLOGY INTERNATIONAL
(2023)
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, Multidisciplinary
Shijie Wei, Junru Wang, Jian Cui, Shanshan Song, Huacong Li, Jiangfeng Fu
Summary: This paper presents a study on ultrasonic-based measurement for the dynamic oil film thickness of fuel pump. The circumferential oil film thicknesses in a journal bearing are measured using a complex model and a resonance model. The minimum oil film thickness is extracted by fitting the measured points with the initial circle. The measured results are verified with classical DHL simulations, and the maximum relative error is shown to be lower than 15%.
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
Materials Science, Characterization & Testing
Pan Dou, Peng Zheng, Yaping Jia, Tonghai Wu, Min Yu, Tom Reddyhoff, Wei-Hsin Liao, Zhongxiao Peng
Summary: This paper presents a unified ultrasonic model that enables accurate measurements of oil film thickness that is widely ranged in a thinly coated bearing. The proposed method's feasibility is validated through experiments.
NDT & E INTERNATIONAL
(2022)
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, 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
Shaoyu Zhu, Xiangjun Zhang
Summary: The modified average Reynolds equation for friction pairs with arbitrary three-dimensional rough surfaces lubricated by couple stress fluid is derived. The performance parameters under various factors, such as couple stress, surface roughness, journal misalignment, and thermal effect, are obtained using the finite difference numerical method. The results show that the surface roughness factor plays an important role in the performance of the friction pairs, even with small nominal eccentricity ratios.
PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART J-JOURNAL OF ENGINEERING TRIBOLOGY
(2022)
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)
Article
Engineering, Mechanical
Liangyan Zheng, Hanhua Zhu, Shidong Fan, Taiwei Yang, Jie Wu, Chunping Wang, Jiyin Cao
Summary: The study highlights the importance of environmentally friendly lubricants in ships due to increasingly prominent marine oil pollution problems. It examines the effects of couple stress and axial motion of the stern shaft on lubrication performance, finding that they have opposite effects on film distribution. Additionally, the results show that couple stress lubricants effectively reduce friction caused by hydrodynamic effects, with the decreasing amplitude remaining relatively constant regardless of axial velocity.
PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART J-JOURNAL OF ENGINEERING TRIBOLOGY
(2022)
Article
Engineering, Mechanical
Liangyan Zheng, Hanhua Zhu, Shidong Fan, Jie Wu, Jiyin Cao
Summary: This study investigates the combined effects of couple stress and surface roughness on the lubrication performance and regime transition of misaligned hydrodynamic journals. New lubrication models considering misalignment angle, couple stress, and surface roughness were developed. Results show that the relationship between the minimum film thickness, maximum film pressure, and friction coefficient with respect to couple stress parameters is opposite to that with respect to misalignment angle. The speed of regime transition and the minimum friction coefficient increase with misalignment angle but decrease with couple stress parameter.
PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART J-JOURNAL OF ENGINEERING TRIBOLOGY
(2022)
Article
Engineering, Mechanical
Busra Duran, Jerome Cavoret, David Philippon, Fabrice Ville, Arnaud Ruellan, Frank Berens
Summary: This study analyzes the changes in the physicochemical properties and tribological performances of gear transmission oils during field operation, finding differences from traditional engine oils.
TRIBOLOGY INTERNATIONAL
(2024)
Article
Engineering, Mechanical
Baocheng Liu, Hongsheng Chen, Jun Zhou, Jing Wang, Wenxian Wang, Xiaochun Chen, Sanxiao Xi
Summary: This study used fast hot pressing sintering to fabricate WC/AlCoCrFeNi2.1 metal matrix composites (MMCs). It was found that the addition of reinforced particles increased the microhardness, nanoindentation and wear resistance of the MMCs. During frictional processes, an oxide film formed, providing material protection, enhancing stability and reducing friction-induced losses.
TRIBOLOGY INTERNATIONAL
(2024)
Article
Engineering, Mechanical
Pradip Kumar Verma, Alok Singh
Summary: This study investigates the mechanical properties and wear resistance of CoMoMnNiV high entropy alloy reinforced aluminium matrix composite processed through stir-squeeze casting assisted with an ultrasonic transducer. The results show significant improvements in mechanical properties and wear resistance, with the composite containing 8 wt% HEA demonstrating the highest resistance to wear. Optical microscopy, SEM, and an optical profilometer were used for a thorough examination of the microstructure and worn surface.
TRIBOLOGY INTERNATIONAL
(2024)
Article
Engineering, Mechanical
Zhenghai Yang, Yingjian Song, Jinlong Jiao, Wenbo Li, Bao Shangguan, Yongzhen Zhang
Summary: This study investigated the friction, wear properties, and current-carrying properties of copper-graphite composites paired with brass C28000. The results showed that the current-carrying properties of the composite materials were excellent, but their wear rate was the main limiting factor. Furthermore, an increase in the thickness of the graphite layer led to an improvement in the uniformity of damage.
TRIBOLOGY INTERNATIONAL
(2024)
Article
Engineering, Mechanical
Moustafa Mahmoud Yousry Zaghloul, Karen Steel, Martin Veidt, Michael T. Heitzmann
Summary: This research evaluates and compares the impact of different material types on the tribological characteristics of Polyamide 6 composites, and finds that glass fiber-reinforced Polyamide 6 exhibits better friction and wear performance under high-pressure velocity factors.
TRIBOLOGY INTERNATIONAL
(2024)
Article
Engineering, Mechanical
Shaoqing Qin, Lida Zhu
Summary: In this paper, the surface and subsurface damage of laser assisted grinding CrCoNi medium entropy alloys were investigated using molecular dynamics simulations. The results showed that the application of laser energy can reduce cutting forces and minimize subsurface damage.
TRIBOLOGY INTERNATIONAL
(2024)
Article
Engineering, Mechanical
Kaikui Zheng, Youxi Lin, Tingzheng Lai, Chenghui Gao, Ming Liu, Zhiying Ren
Summary: The study investigated the use of waste foundry resin-bonded sand as a substitute for copper in resin-based brake material. It found that the waste sand was more favorable for improving the overall friction and wear properties of the material compared to copper. Waste sand benefited the material by forming a friction layer, leading to increased friction coefficient and stability. Brake material with 10-15% waste sand showed excellent heat-fade resistance.
TRIBOLOGY INTERNATIONAL
(2024)
Article
Engineering, Mechanical
Dayang Li, Fanhao Zhou, Yutong Gao, Kun Yang, Huimin Gao
Summary: This article introduces a continuous prediction model based on deep learning for predicting the power output of steam turbines. The model uses long short term memory (LSTM) method to develop a trend prediction model and optimizes the prediction model through feature selection method. Experimental results show that the model outperforms other models in terms of prediction performance.
TRIBOLOGY INTERNATIONAL
(2024)
Article
Engineering, Mechanical
Tomohiro Toyoda, Ryo Yasuike, Toshihiro Noda
Summary: In this study, a elasto-plastic constitutive model of friction incorporating the concept of superloading surface was developed based on the subloading friction model. The proposed model achieves a smooth transition of friction by describing the evolution rule of structure, treating the state with static friction coefficient larger than kinetic friction coefficient as the bulkiness of structure. The positive definiteness of the plastic multiplier, loading condition, and material parameters were derived, and the validity of the proposed model in accordance with the subloading-friction model was confirmed through a stick-slip simulation of a mass-spring system.
TRIBOLOGY INTERNATIONAL
(2024)
Article
Engineering, Mechanical
P. Balaji, B. Surya Rajan, K. Sathickbasha, P. Baskara Sethupathi, Deviga Magadevan
Summary: This study emphasizes the importance of using a variety of solid lubricants with different oxidation temperature regimes to enhance the tribological performance of brake pads.
TRIBOLOGY INTERNATIONAL
(2024)
Article
Engineering, Mechanical
Jian Ma, Yancong Liu, Javad Mostaghimi, Na Zhang
Summary: This paper investigates the influence of preparation strategies on the lubrication properties of surface textures. Three laser scanning strategies are proposed to achieve a sinusoidal textured surface, and the evolution of surface structure and chemical composition is discussed. The findings show that ridge structures enhance anti-wear properties but also increase the friction coefficient. However, the oil cover preparation method prevents the formation of ridges and improves wettability.
TRIBOLOGY INTERNATIONAL
(2024)
Article
Engineering, Mechanical
Mohammad Roostaei, Arvin Taghizadeh Tabrizi, Hossein Aghajani
Summary: In this research, the Al2O3/MoS2 nanocomposite coating layer was successfully applied on the surface of Ti-6Al-4 V alloy. The relation between the surface characteristics and wear resistance of the coating was studied using atomic force microscopy analysis and pin-on-disk wear test method. The results showed that the nanocomposite coating significantly reduced the wear rate and provided an equation to calculate the Lancaster coefficient.
TRIBOLOGY INTERNATIONAL
(2024)
Article
Engineering, Mechanical
Musa Bilgin, Sener Karabulut, Halil Karakoc, Yunus Kayir, Murat Sarikaya
Summary: This study investigates various methods to improve the machinability efficiency of Inconel 718 alloy while considering their effect on microstructural properties. The results show that hot+PMQL, hot+SiCNMQL, and hot+Al2O3-NMQL contribute significantly to the improvement of machinability characteristics. The EBSD analysis also reveals that a limited area is affected by heat in the hot machining environment and that the removal of the heated layer during milling process helps preserve the microstructure.
TRIBOLOGY INTERNATIONAL
(2024)
Article
Engineering, Mechanical
Q. Gao, Y. Fan, Y. G. Wu, J. L. Liu, J. Wang, L. Li
Summary: Fretting wear significantly affects the hysteresis behavior of the contact surface and leads to joint degradation. This study investigates the influence of harmonic normal force on the evolution of interface morphology and contact parameters with fretting wear. The results show that the harmonic normal force can significantly influence the hysteresis loop and the energy dissipation distribution on the contact surface.
TRIBOLOGY INTERNATIONAL
(2024)
Article
Engineering, Mechanical
Benjamin Weiland, Floriane Leclinche, Anis Kaci, Brigitte Camillieri, Betty Lemaire-Semail, Marie -Ange Bueno
Summary: This study presents a systematic approach to generating control signals for a tactile simulator that simulate the touch of textile fabrics. By using a friction modulation tactile surface and acquiring forces from real surfaces with artificial finger mimicking fingerprints, control signals are generated and processed in the frequency domain before sending them to the tactile stimulator. The study focuses on the potential benefits of incorporating fingerprint information in fabric simulations to achieve a more realistic tactile perception. A sensory analysis with 36 participants using the generated control signals showed better discrimination without fingerprint information.
TRIBOLOGY INTERNATIONAL
(2024)
