Article
Engineering, Mechanical
Mert Yusuf Cam, Matteo Giacopini, Daniele Dini, Luca Biancofiore
Summary: Hydrodynamic lubrication plays a fundamental role in mechanical systems by reducing energy losses and preventing mechanical breakdown. The classical linear Reynolds equation is insufficient for describing the lubricant characteristics on engineered surfaces, and non-linearities introduced by wall slip and cavitation need to be considered. Therefore, a modified two-dimensional Reynolds equation is proposed to capture both the cavitation presence and wall slippage, leading to improved accuracy and computational efficiency.
TRIBOLOGY INTERNATIONAL
(2023)
Article
Engineering, Mechanical
S. S. Gamaniel, D. Dini, L. Biancofiore
Summary: This work investigates the influence of fluid viscoelasticity on the performance of lubricated contacts in the presence of cavitation. The study uses the Oldroyd-B model to describe the effect of viscoelasticity and linearizes the equations to analyze the impact of viscoelastic thin films under cavitation conditions.
TRIBOLOGY INTERNATIONAL
(2021)
Article
Engineering, Mechanical
S. Li, A. Kolivand, A. Anisetti
Summary: Using a computational approach, this study quantifies the onset of lubrication starvation for line contacts of rough surfaces under typical automotive gearing conditions. The critical film thickness supply, at which starvation initiates, is determined using a non-Newtonian thermal mixed lubrication model. The study considers various potential influential parameters and employs general linear regression to establish an equation that quantifies the dependence of starvation on statistically significant predictors.
JOURNAL OF TRIBOLOGY-TRANSACTIONS OF THE ASME
(2022)
Article
Chemistry, Multidisciplinary
Evangelos Liamas, Simon D. D. Connell, Anwesha Sarkar
Summary: This study provides a detailed investigation of the frictional behavior of sustainable plant proteins at the nanoscale using bio-relevant surfaces. The results indicate that the main factors influencing the frictional properties of plant proteins are their affinity towards the surface and the degree of protein film hydration. Interactions between plant proteins and mucins lead to improved lubricating properties. This research lays the foundation for the design of sustainable biomaterials and food with optimal nanolubrication performance.
NANOSCALE ADVANCES
(2023)
Article
Materials Science, Multidisciplinary
Manoj Rajankunte Mahadeshwara, Fatima Rosa, Todor Vuchkov, Luis Vilhena, Amilcar Ramalho, Pooja Sharma, Albano Cavaleiro
Summary: In this study, the steel surface was textured with electrochemical processing (ECP) and post-coated with transition metal dichalcogenides (TMD) using a molybdenum-selenium-carbon (MoSeC) film to improve the surface frictional properties of the material. The block-on-ring experiments under lubricated conditions showed that the MoSeC-coated circular patterns exhibited improvements in frictional properties compared to smooth surfaces.
Article
Engineering, Mechanical
Hiba Jendoubi, Olga Smerdova, Noel Brunetiere
Summary: While hydrophobic surfaces can reduce friction by allowing liquid to slip over them, super-hydrophobic surfaces created through texturing with low surface energy material may actually exhibit higher friction coefficients compared to smooth surfaces. This unexpected result could be explained by changes in wetting regime due to high pressure in fluid and potential generation of vortices in the cavities.
Article
Engineering, Mechanical
Wei Zhang, Xiaoyu Chen, Seiji Yamashita, Mitsuhiro Kubota, Hideki Kita
Summary: Frictional characteristics of carbide ceramics sliding against SiC balls in water were measured under various test conditions. The results showed that carbide ceramics can achieve low friction coefficients at 20 and 40 N due to hydrodynamic lubrication and tribochemical reactions. Additionally, B4C ceramic exhibited lower friction coefficients compared to SiC and B4C-SiC ceramics at higher loads of 20 and 40 N in boundary and mixed lubrication regimes.
JOURNAL OF TRIBOLOGY-TRANSACTIONS OF THE ASME
(2022)
Article
Engineering, Mechanical
G. Boidi, P. G. Gruetzmacher, A. Kadiric, F. J. Profito, I. F. Machado, C. Gachot, D. Dini
Summary: This study demonstrated the potential of fast laser texturing techniques in improving the tribological performance of bearings and mechanical components. Dimples were found to reduce friction effectively compared to smooth surfaces, while grooves had less beneficial effects. Additionally, dimples promoted the formation of full film lubrication conditions at lower speeds.
Article
Engineering, Chemical
Y. Zhao, P. L. Wong
Summary: Recent research has found a new lubrication scheme brought by boundary slip effect in lubrication. However, achieving a durable slip coating in elastohydrodynamic lubrication (EHL) is challenging. One possible solution is to apply a slip surface coating onto a substrate with an interlayer, creating a multi-layer structure. This study presents a robust framework for analyzing the effects of coating and interlayer thickness and strength, and develops a general algorithm for investigating the mechanics of boundary slip EHL contact.
Article
Robotics
Jingyi Xu, Tamay Aykut, Daolin Ma, Eckehard Steinbach
Summary: This study focuses on the 6D frictional wrench produced in robot grasping with deformable gripper jaws during nonplanar surface contacts. By combining concepts of differential geometry and Coulomb friction, a 6D frictional wrench for nonplanar surfaces is derived. Additionally, 6D limit surface models are proposed, increasing recall by up to 26.1% over traditional 3D models.
IEEE TRANSACTIONS ON ROBOTICS
(2021)
Article
Engineering, Mechanical
S. Li, A. Kolivand
Summary: This study proposes a rolling contact fatigue model for lubricated gear contacts of rough surfaces, considering crack nucleation and propagation stages. The model uses boundary element approach to describe surface roughness effect on stress concentration and fatigue criterion to find crack nucleation position and life. Through comparisons to experiments, the model's capability is demonstrated, showing significant roughness effect on crack propagation and nucleation.
MECHANISM AND MACHINE THEORY
(2022)
Article
Materials Science, Paper & Wood
H. Okubo, R. Nakae, D. Iba, K. Yamada, H. Hashiba, K. Nakano, K. Sato, S. Sasaki
Summary: This study investigates the tribological properties of a novel biomass material, 100% cellulose nanofiber (CNF) molding. The friction coefficient and wear volume of the CNF molding were found to increase with the test temperature under dry-sliding conditions. Surface analysis revealed amorphization of the CNF molding under high-temperature dry-sliding conditions. The study highlights the dependence of friction and wear performance of 100% CNF moldings on sliding test conditions and the role of amorphization process on their performance.
Article
Engineering, Mechanical
Thomas Geike
Summary: This paper investigates the application of bubble dynamics in mixed lubrication simulation and shows modifications to the Rayleigh-Plesset equation to accurately obtain the time scale for dynamic processes.
FACTA UNIVERSITATIS-SERIES MECHANICAL ENGINEERING
(2021)
Article
Engineering, Mechanical
Gopakumar Parameswaran, Vikram Jayaram, Satish V. Kailas
Summary: The objective of this study was to reduce friction by modifying surfaces using a commercially feasible and scalable approach. Different surface specimens were prepared and tested, and the frictional force plots generated showed different shapes. The balance between adhesion and abrasion phenomena at the contact interface and promoting oil retention were found to be important for achieving low sliding friction.
Article
Engineering, Mechanical
Thi-Na Ta, Jeng-Haur Horng, Yunn-Lin Hwang
Summary: The combination of tribology and mechanical vibration is significant in analyzing and solving practical problems. This study investigates the effects of operating conditions on the tribological and vibration behaviors of lubricating oils and establishes empirical equations to describe the friction-vibration interactions. The results show that the vibration velocity increases with the sliding velocity and lower friction coefficients are observed with a lower combination of vibration velocity to sliding velocity ratio and specific film thickness.
JOURNAL OF TRIBOLOGY-TRANSACTIONS OF THE ASME
(2022)
Correction
Materials Science, Multidisciplinary
L. A. Thimons, A. Gujrati, A. Sanner, L. Pastewka, T. D. B. Jacobs
EXPERIMENTAL MECHANICS
(2022)
Article
Materials Science, Multidisciplinary
C. Haug, D. Molodov, P. Gumbsch, C. Greiner
Summary: Tribological loading induces microstructural changes in metals through dislocation-mediated plastic deformation. Crystal lattice rotations play an important role in friction and wear at the sliding interface, and are influenced by sliding direction and grain orientation.
Article
Engineering, Multidisciplinary
Shoya Mohseni-Mofidi, Lars Pastewka, Matthias Teschner, Claas Bierwisch
Summary: This study explores a numerical approach for soft abrasive flow machining (SAFM) to address fluid-structure interface issues and surface erosion, as well as to investigate the effect of an external magnetic field on machining performance. Results show that a magnetic field of suitable strength can considerably improve the performance of SAFM.
APPLIED MATHEMATICAL MODELLING
(2022)
Article
Materials Science, Multidisciplinary
Wolfram G. Noehring, Jan Griesser, Patrick Dondl, Lars Pastewka
Summary: The surface elastic response of pure Ni, the random alloy FeNiCr, and an average FeNiCr alloy were studied using the surface lattice Green's function. A scheme for computing per-site Green's function was proposed and their per-site variations were studied. The average FeNiCr alloy accurately reproduced the mean Green's function of the full random alloy.
MODELLING AND SIMULATION IN MATERIALS SCIENCE AND ENGINEERING
(2022)
Article
Computer Science, Interdisciplinary Applications
Richard J. Leute, Martin Ladecky, Ali Falsafi, Indre Joedicke, Ivana Pultarova, Jan Zeman, Till Junge, Lars Pastewka
Summary: This paper generalizes the compatibility projection method introduced by Vond.rejc et al. (2014) [24] beyond the Fourier basis while maintaining Fourier-acceleration and fast convergence properties. The proposed method eliminates ringing artifacts and provides an efficient computational homogenization scheme that is equivalent to canonical finite-element formulations on fully structured grids.
JOURNAL OF COMPUTATIONAL PHYSICS
(2022)
Article
Materials Science, Multidisciplinary
Antoine Sanner, Lars Pastewka
Summary: This study focuses on the adhesion hysteresis of soft elastic spheres with low roughness or weak heterogeneity, introducing a crack-perturbation model to describe the indentation process and contact shapes.
The crack-perturbation model accurately predicts contact shapes and hysteresis force-penetration curves, offering a more efficient computational approach compared to traditional methods.
JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS
(2022)
Article
Engineering, Chemical
Hannes Holey, Andrea Codrignani, Peter Gumbsch, Lars Pastewka
Summary: The cornerstone of thin-film flow modeling is the Reynolds equation, but its derivation is based on specific assumptions about the fluid constitutive behavior, limiting its applicability in multiscale scenarios. In this study, a method is introduced to treat the macroscopic flow evolution and local cross-film stresses as separate yet coupled problems, overcoming this limitation and validating the approach using examples.
Article
Engineering, Mechanical
Ali Riza Durmaz, Erik Natkowski, Nikolai Arnaudov, Petra Sonnweber-Ribic, Stefan Weihe, Sebastian Munstermann, Chris Eberl, Peter Gumbsch
Summary: This study proposes a validation framework where a fatigue test is simulated by embedding measured microstructures into the specimen geometry and adopting an approximation of the experimental boundary conditions. A phenomenological crystal plasticity model is applied to predict deformation in ferritic steel, and the hotspots in commonly used fatigue indicator parameter maps are compared with damage segmented from micrographs. The framework is published for benchmarking future micromechanical fatigue models.
INTERNATIONAL JOURNAL OF FATIGUE
(2022)
Article
Chemistry, Physical
Xin Fang, Jihong Wen, Li Cheng, Dianlong Yu, Hongjia Zhang, Peter Gumbsch
Summary: This research demonstrates a design paradigm for creating robust robotic metamaterials using versatile gear clusters. The design allows for continuous tuning of elastic properties while maintaining stability and robust maneuverability, even under heavy loads. The gear-based metamaterials offer excellent properties such as tunable Young's modulus, shape morphing, and fast response.
Article
Multidisciplinary Sciences
Nikolay T. Garabedian, Paul J. Schreiber, Nico Brandt, Philipp Zschumme, Ines L. Blatter, Antje Dollmann, Christian Haug, Daniel Kuemmel, Yulong Li, Franziska Meyer, Carina E. Morstein, Julia S. Rau, Manfred Weber, Johannes Schneider, Peter Gumbsch, Michael Selzer, Christian Greiner
Summary: This paper discusses the lack of FAIR (Findable, Accessible, Interoperable, and Reusable) data and metadata in experimental tribology and proposes a scalable framework for generating FAIR data. Through collaboration with developers, crowdsourcing controlled vocabulary, ontology building, and the use of digital tools, this paper demonstrates a collection of scalable non-intrusive techniques to improve the lifespan, reliability, and reusability of experimental tribological data.
Article
Chemistry, Multidisciplinary
Navid Hussain, Torsten Scherer, Chittaranjan Das, Janis Heuer, Rafaela Debastiani, Peter Gumbsch, Jasmin Aghassi-Hagmann, Michael Hirtz
Summary: This study explores the interaction between capillary-printed Galinstan and gold surfaces, revealing the spreading process of liquid metals on gold films and the formation of intermetallic nanostructures. By utilizing various microscopy techniques, a comprehensive understanding of the material interaction between LM and gold is achieved.
Article
Materials Science, Multidisciplinary
Kolja Zoller, Patric Gruber, Michael Ziemann, Alexander Goertz, Peter Gumbsch, Katrin Schulz
Summary: Microwires have gained increasing interest for miniaturizing structural components. Understanding the deformation behavior of microwires is crucial for assessing their applicability and lifespan in specific components. This study analyzes the microstructure evolution of single crystalline gold microwires under torsion, specifically for high-symmetry crystal orientations (100), (110), and (111), using simulation and experimental results. The classification of slip systems can be predicted through theoretical considerations, and it is found that slip system activity, stress relaxation mechanism, and dislocation density depend on specific slip system groups.
COMPUTATIONAL MATERIALS SCIENCE
(2023)
Article
Materials Science, Multidisciplinary
Kai Xia, Zheqin Dong, Qing Sun, Rafaela Debastiani, Sida Liu, Qihao Jin, Yang Li, Ulrich W. Paetzold, Peter Gumbsch, Uli Lemmer, Yolita M. Eggeler, Pavel A. Levkin, Gerardo Hernandez-Sosa
Summary: 3D-printed conductive structures with customized properties are fabricated using digital light processing technology and inkjet printing. By optimizing the deposition conditions, conductive structures with sheet resistance <2 ohm sq(-1) are achieved. The integration of an inkjet-printed photodetector onto the nanoporous substrate demonstrates the potential for additive manufacturing of functional 3D-printed optoelectronic devices.
ADVANCED MATERIALS TECHNOLOGIES
(2023)
Article
Physics, Multidisciplinary
Hannes Holey, Peter Gumbsch, Lars Pastewka
Summary: This study employs molecular dynamics simulations to investigate flow at the molecular scale and explores the influence of in-plane wavelengths. By probing the long wavelength limit in thermodynamic equilibrium, anomalous relaxation of density and longitudinal momentum fluctuations is observed, which can be described by an effective continuum theory.
PHYSICAL REVIEW LETTERS
(2023)
Article
Chemistry, Physical
Daniel Maksuta, Siddhesh Dalvi, Abhijeet Gujrati, Lars Pastewka, Tevis D. B. Jacobs, Ali Dhinojwala
Summary: Friction is a major cause of energy loss in moving parts, and understanding the effect of surface roughness on friction is crucial. This study shows that adhesive frictional dissipation plays a dominant role and that roughness-induced oscillations control both viscoelastic dissipation and molecular detachment process. The data can be collapsed onto a universal curve when certain scaling factors are applied.
