Article
Engineering, Electrical & Electronic
Marko Tosic, Roland Larsson, Karsten Stahl, Thomas Lohner
Summary: This study investigates the elastohydrodynamic lubrication (EHL) between nonconjugate meshing tooth flanks of a worm gear. The contact is characterized by a slender elliptical shape and high sliding. A validated numerical EHL model considering non-Newtonian, thermal, and transient effects is used to analyze the complete contact area of the worm gear. The study identifies and discusses the design factors that influence EHL film formation in worm gears.
Article
Engineering, Mechanical
Yiqian Cheng, Qiang He, Weifeng Huang, Ying Liu, Yanwen Li, Decai Li
Summary: Physics-informed neural networks (PINNs) have been used to solve partial differential equations (PDEs) in various fields. In this study, a deep learning computational framework called HL-nets is proposed for computing the flow field of hydrodynamic lubrication with cavitation effects. Different cavitation conditions and penalty/imposing schemes are implemented to accurately solve the Reynolds equation. The results demonstrate the accuracy and potential of HL-nets in simulating hydrodynamic lubrication involving cavitation.
TRIBOLOGY INTERNATIONAL
(2023)
Article
Engineering, Mechanical
Michael Rom
Summary: This study proposes a method for solving the Reynolds equation with cavitation modeling using physics-informed neural networks (PINNs). The PINN solves multiple problems simultaneously and generalizes well by extending its inputs with parameters such as the relative eccentricity. Accurate pressure and liquid ratio predictions for further values of the relative eccentricity can be obtained by just evaluating the PINN, taking less than a second. Solutions for a journal bearing test case are compared with finite difference solutions.
TRIBOLOGY INTERNATIONAL
(2023)
Article
Engineering, Mechanical
Quentin Allen, Bart Raeymaekers
Summary: We investigate the convergence of elastohydrodynamic lubrication (EHL) simulations for textured slider bearings, which are computationally expensive due to the coupling of equations and additional simulation requirements. We quantitatively analyze the convergence of EHL simulations for textured slider bearings with various parameters and conclude that a careful consideration of discretization, convergence metric, and criterion is crucial for achieving accurate numerical simulations. Our study also highlights the potential of a well-designed convergence analysis in reducing computational costs.
Article
Engineering, Chemical
Takeshi Kunishima, Gaetan Bouvard, Jean-Christophe Abry, Vincent Fridrici, Philippe Kapsa
Summary: In this study, the friction mechanism of polyamide 66 in contact with a steel counterpart lubricated with additive-free polyalphaolefin8 oil was discussed, considering various parameters. The theoretical minimum oil film thickness was calculated and a master curve of the relationship between Lambda and the friction coefficient was proposed. The contributions of the oil film and lubricated solid/solid contact to the friction coefficient were also discussed. Additionally, the friction mechanism using glass fiber-reinforced PA66 composite was investigated and compared to unreinforced PA66.
Article
Engineering, Mechanical
Marko Tosic, Roland Larsson, Thomas Lohner
Summary: This study focuses on the thermal effects of slender elastohydrodynamically lubricated (EHL) contacts under high sliding, finding that thermal effects can result in a viscosity wedge and divert oil flow to the contact sides.
Article
Engineering, Mechanical
N. Rogkas, L. Vasilopoulos, V. Spitas
Summary: This work presents a comprehensive formulation of the equations governing the lubrication and the lock-up phases of an engaging wet clutch. A finite element model is established through the coupling of the Reynolds equation of the fluid film model with the dynamic force and torque equilibrium equations of the two-disc system. An efficient hybrid simulation technique is introduced to solve the problem and capture the rapidly evolving transient phenomena at the start of the engagement phase, which later settles into a quasi-static one.
INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES
(2023)
Article
Engineering, Chemical
Shuangbiao Liu, Q. Jane Wang, Yip-Wah Chung, Stephen Berkebile
Summary: The article discusses the lubrication-contact interface conditions (LCICs) and proposes mathematical LCICs to address the interface issue between fluid lubrication and solid contacts. Through practical testing, a new mixed/boundary elastohydrodynamic lubrication solver has been successfully developed, capable of accurately capturing film thickness and pressure behaviors involving solid contacts.
Article
Mechanics
Giovanni Cimatti
Summary: Porous metal bearings are commonly used in small and micro devices, and the pressure in a porous bearing is found to be lower than in a non-porous bearing. The study focuses on solving the Reynolds equation coupled with the Laplace equation to compute the pressure, and introduces a variational formulation for the relevant boundary value problem.
Article
Engineering, Mechanical
Xinming Li, Feng Guo, Gerhard Poll, Yang Fei, Ping Yang
Summary: This study investigates the evolution of grease films in rolling elastohydrodynamic lubrication (EHL) contacts with glass disc revolutions. The patterns of grease film evolution were found to be highly related to speed ranges and grease structures, shedding light on mechanisms such as transfer of thickener lumps, decay in film thickness due to starvation, and the formation of an equilibrium film. The primary mechanisms governing grease film formation in different lubricated contacts were clarified through the research.
Article
Engineering, Mechanical
Shi Chen, Nian Yin, Xiaojiang Cai, Zhinan Zhang
Summary: The study focuses on a discretization formula of the Reynolds equation based on the Crank-Nicolson method, utilizing Gauss-Seidel relaxation and distribution relaxation for the linear operators of pressure. An estimation framework is developed to investigate the relative error in the Reynolds equation. Experimental results show that the proposed method performs well in handling contact and wavy surfaces.
FRONTIERS OF MECHANICAL ENGINEERING
(2021)
Article
Engineering, Chemical
Quentin Allen, Bart Raeymaekers
Summary: This study uses soft elasto-hydrodynamic lubrication simulations to evaluate the lubricant film thickness in textured hard-on-soft bearings with different cavitation models. The findings suggest a significant difference in lubricant film thickness calculated by various cavitation models based on the texture design parameters.
Article
Engineering, Mechanical
Gabriel W. Rodrigues, Fabiano L. Oliveira, Llmar F. Santos, Marco L. Bittencourt
Summary: This paper compares different dynamical models, cavitation procedures, and numerical methods for simulating hydrodynamic lubricated bearings of internal combustion engines. The study found that different dynamical models differed in predicting journal orbits, while the finite element method with Giacopini's cavitation model showed improved numerical stability for the three types of engines.
INDUSTRIAL LUBRICATION AND TRIBOLOGY
(2022)
Article
Mechanics
Martin H. Essink, Anupam Pandey, Stefan Karpitschka, Cornelis H. Venner, Jacco H. Snoeijer
Summary: Elastohydrodynamic lubrication, also known as soft lubrication, is a key physical mechanism to minimize friction and wear, where the thickness of the lubricant layer is related to parameters like entrainment velocity and mechanical loading. This work provides an overview of soft lubrication mechanisms for two-dimensional cylinders in contact with compliant walls, focusing on thin elastic coatings and establishing missing scaling laws through analysis of elastohydrodynamic boundary layers.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Engineering, Chemical
Mostafa Faraji, Alexander Seitz, Christoph Meier, Wolfgang A. Wall
Summary: This work presents a new model and numerical formulation for lubricated contact problems involving deformable 3D solid bodies and a fluid film. The model considers frictional contact tractions and hydrodynamic fluid tractions at each local point on the contact surface, and covers the entire range of lubrication. The finite element method is used for spatial discretization and several benchmark tests demonstrate the accuracy of the model.
Article
Mathematics, Interdisciplinary Applications
M. Rezaee-Hajidehi, K. Tuma, S. Stupkiewicz
Summary: This study demonstrates that the logarithmic strain and its derivatives can be accurately approximated using Pade approximants of the tensor logarithm. Compared favorably to the truncated Taylor series, the Pade approximants show higher accuracy and computational efficiency. Through finite-element computations, the performance of Pade approximants in Hencky-type hyperelasticity problems is further verified.
COMPUTATIONAL MECHANICS
(2021)
Article
Mechanics
Mohsen Rezaee-Hajidehi, Stanislaw Stupkiewicz
Summary: This paper investigates the modelling of propagating instabilities and transformation patterns in NiTi tubes under combined tension-torsion loading. The developed model successfully represents experimentally observed effects, including the non-uniform transformation under tension-dominated loading and the importance of tension-compression asymmetry, transverse isotropy, and deformation-dependent response. Ambiguities in determination of the yield locus for tension-dominated loading are highlighted, emphasizing the impact on interpretation of experimental results.
INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES
(2021)
Article
Engineering, Multidisciplinary
Marco Magliulo, Jakub Lengiewicz, Andreas Zilian, Lars A. A. Beex
Summary: This contribution presents the extensions of beam-to-beam and beam-inside-beam contact schemes towards frictional interactions, which can account for friction sliding in both axial and circumferential directions. The penalty formulation is used to treat contact constraints, and automatic differentiation techniques are utilized to derive implementations. Simulations involving large sliding displacements and deformations are presented for both beam-to-beam and beam-inside-beam schemes.
INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING
(2021)
Article
Engineering, Multidisciplinary
K. Tuma, M. Rezaee-Hajidehi, J. Hron, P. E. Farrell, S. Stupkiewicz
Summary: This study investigates large-scale 3D martensitic microstructure evolution problems using a finite-element discretization of a finite-strain phase-field model. The model incorporates various crystallography of transformation and elastic anisotropy of the phases, and demonstrates robustness and good parallel scaling performance in a 3D simulation of microstructure evolution during nano-indentation. The finite-element discretization relies on the PETSc solver library and efficiently solves the large systems of linear equations arising from the model.
COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING
(2021)
Article
Mechanics
Mohsen Rezaee-Hajidehi, Stanislaw Stupkiewicz
Summary: In this work, a micromorphic formulation of the phase-field model is developed within the incremental energy minimization framework, which allows for a more accurate capture of interfacial energy and size effects. By applying the augmented Lagrangian technique, the non-smooth incremental minimization problem is successfully transformed into a smooth and unconstrained saddle-point problem.
INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES
(2021)
Article
Mechanics
Przemyslaw Sadowski, Katarzyna Kowalczyk-Gajewska, Stanislaw Stupkiewicz
Summary: The Mori-Tanaka model combines simplicity and good predictive capabilities, but the use of the Perzyna-type viscoplasticity model may lead to spurious softening in the macroscopic response.
EUROPEAN JOURNAL OF MECHANICS A-SOLIDS
(2021)
Article
Robotics
Benoit Piranda, Pawel Chodkiewicz, Pawel Holobut, Stephane Bordas, Julien Bourgeois, Jakub Lengiewicz
Summary: A distributed framework is proposed for predicting mechanical overloading during reconfiguration of a modular robot, with a simplified instability detection procedure provided. The algorithm's effectiveness is verified through simulations and real-world experiments.
IEEE TRANSACTIONS ON ROBOTICS
(2021)
Editorial Material
Mechanics
Davide Bigoni, Samuel Forest, Stanislaw Stupkiewicz
INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES
(2022)
Article
Materials Science, Multidisciplinary
Mohsen Rezaee-Hajidehi, Przemyslaw Sadowski, Stanislaw Stupkiewicz
Summary: A finite-strain phase-field model is proposed to study the coupled deformation twinning and crystal plasticity. Twinning is treated as a volume-preserving stretch and a micromorphic formulation is employed. In the model, each pair of conjugate twinning systems is represented by a single twin deformation variant, and a single order parameter is used to consistently describe the two conjugate twinning systems.
JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS
(2022)
Article
Engineering, Mechanical
M. Rys, S. Stupkiewicz, H. Petryk
Summary: A new model of gradient crystal plasticity has been developed, which includes the incompatibility of plastic deformation field in two different ways simultaneously. The significance of the two effects depends on the values of material parameters, as demonstrated by calculations of 1D and 3D examples for a Cu single crystal.如果第二种方式占主导地位，那么Cosserat公式仅提供了一种规范化，然后该模型可以用来预测尺寸效应。
INTERNATIONAL JOURNAL OF PLASTICITY
(2022)
Article
Engineering, Biomedical
T. Lavigne, A. Mazier, A. Perney, S. P. A. Bordas, F. Hild, J. Lengiewicz
Summary: This study demonstrated the feasibility of using FE-based DVC technology to measure the deformation of female breast tissues in different body positions, successfully capturing the large displacement field of hard/soft tissue samples and providing a new approach for capturing large tissue deformations.
JOURNAL OF THE MECHANICAL BEHAVIOR OF BIOMEDICAL MATERIALS
(2022)
Article
Engineering, Multidisciplinary
T. Lavigne, S. P. A. Bordas, J. Lengiewicz
Summary: We propose an optimization framework for identifying material parameters and contact traction field of a soft body in contact from two measured deformed geometries. The framework parametrizes the missing contact traction field and incorporates it into the inverse+forward hyper-elasticity formulation. We provide the continuum and finite element formulation, as well as the direct differentiation method of sensitivity analysis for efficient gradient computation.
COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING
(2023)
Article
Engineering, Mechanical
Mohsen Rezaee-Hajidehi, Karel Tuma, Stanislaw Stupkiewicz
Summary: Direct experimental characterization of indentation-induced martensitic microstructures in pseudoelastic SMAs is not possible. In this study, the phase-field method and a finite-element-based computational model are used to analyze martensitic phase transformation during nanoindentation. The results provide a detailed understanding of microstructures and highlight the role of finite-deformation effects and elastic anisotropy. This study also investigates the martensitic transformation in NiTiPd with varying Pd content and demonstrates the dominant role of transformation volume change and interfacial energy at small scales.
INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES
(2023)
Article
Materials Science, Multidisciplinary
Saurabh Deshpande, Raul I. Sosa, Stephane P. A. Bordas, Jakub Lengiewicz
Summary: Deep learning surrogate models are used as a cost-effective alternative to conventional numerical techniques for accelerating scientific simulations. However, their application in complex real-world examples remains challenging. This study demonstrates three neural network architectures for efficiently learning non-linear deformations of solid bodies, including CNN U-NET, MAgNET (graph U-NET), and Perceiver IO. The performance of these networks is compared on benchmark examples, showing their accuracy in predicting non-linear mechanical responses of soft bodies.
FRONTIERS IN MATERIALS
(2023)
Article
Mechanics
Mohsen Rezaee-Hajidehi, Stanislaw Stupkiewicz
Summary: We conducted a comprehensive modeling study to investigate the propagating instabilities in NiTi tubes under proportional axial-torsion loading, based on the experimental work of Reedlunn et al. (2020). Our study focused on the unique longitudinal transformation bands observed in torsion-dominated loading paths. We employed a previously-developed gradient-enhanced model of pseudoelasticity and adapted it to incorporate the residual stresses, and our finite-element setup included a simplified frictional contact model to account for the impact of collet grips on the NiTi tubes. The results demonstrated the capability of our model to capture subtle features of the observed transformation patterns, and suggested that the combination of residual stresses and collet grips facilitated the formation of longitudinal bands.
INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES
(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)
