Article
Engineering, Mechanical
Simon Pfeil, Hauke Gravenkamp, Fabian Duvigneau, Elmar Woschke
Summary: A semi-analytical solution of the Reynolds equation is developed based on the scaled boundary finite element method (SBFEM), combining it with a nonlinear cavitation model. The resulting bearing forces are in good agreement with a standard numerical reference solution.
INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES
(2023)
Article
Engineering, Mechanical
Erwan Fourt, Mihai Arghir
Summary: This study compares the homogenization and multiscale methods for solving the compressible Reynolds equation with irregular coefficients, showing both methods to be reliable and efficient tools for this task.
TRIBOLOGY INTERNATIONAL
(2022)
Article
Mathematics, Applied
Sivaporn Phumichot, Waritsara Kuntiya, Kanyuta Poochinapan, Pariwate Varnakovida, Chalump Oonariya, Ben Wongsaijai
Summary: In this paper, the author introduces the complex regularized long wave (RLW) equation using the basic one-way propagator and transforms it into a system of nonlinear equations. By adopting a consequence nonlinear system, they derive an energy conservation law of the complex RLW equation. They also investigate how the Ansatz method and a numerical scheme can be applied to find and solve solitary wave solutions of the model respectively.
MATHEMATICAL METHODS IN THE APPLIED SCIENCES
(2023)
Article
Multidisciplinary Sciences
Ali Abbaspur, Mahmood Norouzi, Pooria Akbarzadeh, Seyyed Amirreza Vaziri, Melika Mokhtari Sharghi, Kyung Chun Kim, Mirae Kim
Summary: This paper presents a novel analytical solution for journal-bearing viscoelastic lubrication using the perturbation method. The investigation focuses on the impact of characteristic parameters such as mobility factor, eccentricity ratio, and Weissenberg number on the fluid film pressure distribution, load capacity, and shear stress.
SCIENTIFIC REPORTS
(2023)
Article
Engineering, Mechanical
Elsayed K. Elsayed, Hussein Sayed, T. A. El-Sayed
Summary: This study evaluates the first- and second-order bearing coefficients of an inclined pad hydrodynamic thrust bearing to improve the accuracy of modeling thrust bearings. The results show that misalignment angle and film thickness have a clear effect on the dynamic coefficients, while changing the rotational speed has no effect on the damping coefficients. The study also investigates the axial force and moments and dynamic coefficients of an inclined pad thrust bearing.
JOURNAL OF VIBRATION ENGINEERING & TECHNOLOGIES
(2023)
Article
Thermodynamics
Ankur Jain, Long Zhou, Mohammad Parhizi
Summary: This paper presents a theoretical analysis of a one-dimensional multilayer heat transfer problem with diffusion, advection and linear temperature-dependent heat generation. It explores the orthogonality of eigenfunctions and the explicit expression for the eigenequation, focusing on a special case of a two-layer body. The research reveals the impact of various problem parameters on the appearance of imaginary eigenvalues, emphasizing the importance of balance between heat generation, diffusion, and advection in determining thermal runaway.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2021)
Article
Mathematics, Interdisciplinary Applications
Sarmad A. Altaie, Nidal Anakira, Ali Jameel, Osama Ababneh, Ahmad Qazza, Abdel Kareem Alomari
Summary: This article extends the analytical scheme of the homotopy analysis method to develop an approximate analytical solution for Fuzzy Partial Differential Equations. By utilizing powerful tools and concepts, it ensures high precision in fuzzy environments and demonstrates efficiency in linear and nonlinear cases of Fuzzy Reaction-Diffusion Equation and Fuzzy Wave Equation.
FRACTAL AND FRACTIONAL
(2022)
Article
Mathematics
Ruifang Wang, Jianwen Liu, Fabao Gao
Summary: This paper presents an analytic solution for particles in a charged dilaton black hole using the two-timing scale method. The constructed solution is in surprising agreement with the exact numerical solution. It reveals how the physical characteristics of the particle flow, such as viscosity, temperature, and pressure, affect the black hole properties. The study also discusses the relationship between the critical temperature and the charge, as well as the dilaton parameter, during a phase transition of the charged dilaton black hole.
Article
Mechanics
Anil Kumar Sharma, Sasanka Sekhar Sinha, Rajesh Kumar, Subir Kumar Saha
Summary: The paper presents a semi-analytical solution for static equilibrium analysis, demonstrating the limitations of numerical methods in such scenarios. It also provides guidelines on choosing initial guesses to accelerate solution convergence.
INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES
(2022)
Article
Multidisciplinary Sciences
Galal M. Moatimid, T. S. Amer
Summary: This paper investigates the stability analysis of a rocking rigid rod using a time-delayed square position and velocity. The time delay provides additional safety for the nonlinear vibrating system under consideration. The study is relevant due to the recent focus on time-delayed technologies and the coupling of time delay with the modified Homotopy perturbation method (HPM) in this research.
SCIENTIFIC REPORTS
(2023)
Article
Mathematics
Kholoud Saad Albalawi, Ibtehal Alazman, Jyoti Geetesh Prasad, Pranay Goswami
Summary: This research work focuses on solving the n-generalized Korteweg-de Vries (KdV) equation in a fractional sense using a combination of the Sumudu transform and the Adomian decomposition method. This method offers significant advantages for solving both linear and nonlinear differential equations. It provides an easier way to obtain solutions for fractional-order PDEs with less computing effort.
Article
Engineering, Multidisciplinary
S. C. Shiralashetti, M. H. Kantli, A. B. Deshi
Summary: This paper developed a wavelet lifting scheme using orthogonal and biorthogonal wavelets for the numerical solution of dynamic Reynolds equation for micropolar fluid lubrication, showing higher accuracy and speed of convergence in lesser computational time compared to existing methods. Examples given in the paper demonstrate the applicability and attractiveness of the proposed method.
INTERNATIONAL JOURNAL OF COMPUTATIONAL METHODS
(2021)
Article
Physics, Multidisciplinary
Alessio Zaccone
Summary: We present an analytical derivation of the volume fractions for random close packing in both 3D and 2D, and compare the derived values with those reported in the literature using different methods. The derivation suggests that random close packing corresponds to the onset of mechanical rigidity and is determined by the coordination number. The article also points out the possibility of achieving volume fractions above the maximum random jammed state by creating some order, with the coordination number at the fcc limit acting as a boundary condition.
PHYSICAL REVIEW LETTERS
(2022)
Article
Engineering, Mechanical
Rongrong Qiao, Yuhan Hu
Summary: This article proposes a model to analyze the impact of word of mouth on consumers' purchase choices and quantitatively analyzes the effects of traditional WOM and IWOM on purchase decisions through numerical simulations, providing relevant suggestions for product marketing.
NONLINEAR DYNAMICS
(2023)
Article
Engineering, Chemical
Feng Du
Summary: This study builds an analytical theory to explain the friction force on ice and reveals that a dynamic balance between ice melting and water squeezing regulates the thickness of the self-lubricating interstitial meltwater layer, ensuring low friction on ice.
Article
Engineering, Mechanical
R. Bulin, S. Dyk, M. Hajzman
Summary: This paper discusses the modeling and dynamic analysis of thin or slender flexible bodies with axial motion, contacts, and friction interaction. The combination of the absolute nodal coordinate formulation and the classical finite element method is used, taking into account interaction phenomena such as fluid flow, contact forces, gravitation, and buoyancy forces. The research reveals interesting conclusions about the rod drop time affected by vibrating guide thimbles in the nuclear control rod drop problem.
NONLINEAR DYNAMICS
(2021)
Article
Engineering, Mechanical
Vaclav Houdek, Lubos Smolik, Zdenek Kubin
Summary: This article provides an experimental method for localizing an impact point in three-dimensional structures using a redundant sensor array. The method involves measuring the relative times of arrival of the travelling wave and estimating the times of arrival using continuous wavelet transform and optimal interval partitioning. The article also takes into account the varying wave speeds between the impact point and the measurement points, which reduces the accuracy of traditional triangulation and multilateration methods.
MECHANICAL SYSTEMS AND SIGNAL PROCESSING
(2022)
Article
Acoustics
Lubos Smolik, Jan Rendl, Milan Omasta, Miroslav Byrtus, Petr Sperka, Pavel Polach, Martin Hartl, Michal Hajzman
Summary: This paper investigates the effects of mechanically induced textures on the stability of journal bearings, focusing on lightly loaded bearings commonly used in vertical rotors and microturbines. The results show that textures near the minimum oil film thickness can improve stability at low loads, but have little effect at a specific load of 0.15 MPa. The paper also discusses computational methods for dealing with cavitation and highlights the sensitivity of numerical results to the density of computational mesh.
JOURNAL OF SOUND AND VIBRATION
(2023)
Article
Engineering, Mechanical
Stepan Dyk, Jan Rendl, Radek Bulin, Lubos Smolik
Summary: This paper focuses on modelling local phenomena in the ball-and-socket pivot of tilting pad journal bearings and analyzes the influence of nonlinear normal force and friction forces on the bearing's dynamic behavior. Unlike previous studies that use the Hertz theory, this research adopts a conformal sphere-to-sphere contact model and the Bengisu-Akay and LuGre models to describe static and dynamic friction. It also considers effects like presliding, which has not been utilized in simulating the dynamics of tilting pad journal bearings before. The paper further discusses the influence of model parameters, which is critical for accurately predicting nonlinear behavior using the LuGre model.
NONLINEAR DYNAMICS
(2023)
Article
Engineering, Mechanical
Jan Rendl, Miroslav Byrtus, Stepan Dyk, Lubos Smolik
Summary: This work investigates the impact of forces due to rotating unbalance and pressure gradients in the oil film on rotating machinery supported on journal bearings. The analysis focuses on the sub-synchronous motion of a rigid rotor supported on cylindrical journal bearings at rotor speeds lower than the threshold speed for oil whirl. It is found that sub-synchronous vibration can occur before reaching the threshold speed and that the underlying period-doubling bifurcation depends on the amount of rotating unbalance. The rotor response and stability are analyzed using a numerical continuation method and validated through time simulations.
NONLINEAR DYNAMICS
(2023)
Article
Engineering, Mechanical
Lubos Smolik, Stepan Dyk, Jan Rendl
Summary: Rotating unbalance is a major cause of high vibration levels in turbochargers. Current studies view rotating unbalance as a series of static unbalances and emphasize their allocation and orientation. However, the real-world rotors' displaced mass or material nonhomogeneity leads to dynamic unbalance, which results in nonzero products of inertia relative to the axis of rotation. This research uses a multi-body dynamics approach to describe the additional inertial forces caused by dynamic unbalance, which amplifies synchronous vibration and induces various types of asynchronous motions.
INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES
(2023)
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)
