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Dynamically induced friction reduction in micro-structured interfaces. Sci Rep 2021; 11:8094. [PMID: 33854116 PMCID: PMC8046794 DOI: 10.1038/s41598-021-87484-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Accepted: 03/19/2021] [Indexed: 11/11/2022] Open
Abstract
We investigate the dynamic behavior of a regular array of in-plane elastic supports interposed between a sliding rigid body and a rigid substrate. Each support is modelled as a mass connected to a fixed pivot by means of radial and tangential elastic elements. Frictional interactions are considered at the interface between the supports and the sliding body. Depending on the specific elastic properties of the supports, different dynamic regimes can be achieved, which, in turn, affect the system frictional behavior. Specifically, due to transverse microscopic vibration of the supports, a lower friction force opposing the macroscopic motion of the rigid body can be achieved compared to the case where no supports are present and rubbing occurs with the substrate. Furthermore, we found that the supports static orientation plays a key role in determining the frictional interactions, thus offering the chance to specifically design the array aiming at controlling the resulting interfacial friction force.
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Skondras-Giousios D, Karkalos NE, Markopoulos AP. Finite element simulation of friction and adhesion attributed contact of bio-inspired gecko-mimetic PDMS micro-flaps with SiO 2spherical surface. BIOINSPIRATION & BIOMIMETICS 2020; 15:066004. [PMID: 32480387 DOI: 10.1088/1748-3190/ab983e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2019] [Accepted: 06/01/2020] [Indexed: 06/11/2023]
Abstract
The remarkable tribological attributes of the gecko feet have grown much interest in the field of biomimetic tribology over the past two decades. It has been shown that the complexity of friction and adhesion phenomena made it difficult to transfer these exceptional properties into fully functional smart, dry, micro patterned adhesives. The latter, combined with the relative lack of literature on computational oriented studies on these phenomena, is the motive of the current work. Here, a 2D time-dependent finite element model of friction and adhesion attributed contact of polydimethysiloxane (PDMS) micro flaps with a smooth SiO2spherical surface is presented. The model is tested through simulations concerning changes in the disc curvature, the flap density, as well as different disc mounting heights, representing the effect of preload. Furthermore, the effect of tribological parameters of adhesion and friction coefficient is discussed. Finally, the effect of the use of two hyperelastic material models was examined.
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Affiliation(s)
- D Skondras-Giousios
- School of Mechanical Engineering, Laboratory of Manufacturing Technology, National Technical University of Athens, Heroon Polytechniou 9, 15780, Athens, Greece
| | - N E Karkalos
- School of Mechanical Engineering, Laboratory of Manufacturing Technology, National Technical University of Athens, Heroon Polytechniou 9, 15780, Athens, Greece
| | - A P Markopoulos
- School of Mechanical Engineering, Laboratory of Manufacturing Technology, National Technical University of Athens, Heroon Polytechniou 9, 15780, Athens, Greece
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Multi-Scale Surface Texturing in Tribology—Current Knowledge and Future Perspectives. LUBRICANTS 2019. [DOI: 10.3390/lubricants7110095] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Surface texturing has been frequently used for tribological purposes in the last three decades due to its great potential to reduce friction and wear. Although biological systems advocate the use of hierarchical, multi-scale surface textures, most of the published experimental and numerical works have mainly addressed effects induced by single-scale surface textures. Therefore, it can be assumed that the potential of multi-scale surface texturing to further optimize friction and wear is underexplored. The aim of this review article is to shed some light on the current knowledge in the field of multi-scale surface textures applied to tribological systems from an experimental and numerical point of view. Initially, fabrication techniques with their respective advantages and disadvantages regarding the ability to create multi-scale surface textures are summarized. Afterwards, the existing state-of-the-art regarding experimental work performed to explore the potential, as well as the underlying effects of multi-scale textures under dry and lubricated conditions, is presented. Subsequently, numerical approaches to predict the behavior of multi-scale surface texturing under lubricated conditions are elucidated. Finally, the existing knowledge and hypotheses about the underlying driven mechanisms responsible for the improved tribological performance of multi-scale textures are summarized, and future trends in this research direction are emphasized.
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Vanossi A, Dietzel D, Schirmeisen A, Meyer E, Pawlak R, Glatzel T, Kisiel M, Kawai S, Manini N. Recent highlights in nanoscale and mesoscale friction. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2018; 9:1995-2014. [PMID: 30116691 PMCID: PMC6071713 DOI: 10.3762/bjnano.9.190] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Accepted: 06/27/2018] [Indexed: 05/31/2023]
Abstract
Friction is the oldest branch of non-equilibrium condensed matter physics and, at the same time, the least established at the fundamental level. A full understanding and control of friction is increasingly recognized to involve all relevant size and time scales. We review here some recent advances on the research focusing of nano- and mesoscale tribology phenomena. These advances are currently pursued in a multifaceted approach starting from the fundamental atomic-scale friction and mechanical control of specific single-asperity combinations, e.g., nanoclusters on layered materials, then scaling up to the meso/microscale of extended, occasionally lubricated, interfaces and driven trapped optical systems, and eventually up to the macroscale. Currently, this "hot" research field is leading to new technological advances in the area of engineering and materials science.
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Affiliation(s)
- Andrea Vanossi
- CNR-IOM Democritos National Simulation Center, Via Bonomea 265, 34136 Trieste, Italy
- International School for Advanced Studies (SISSA), Via Bonomea 265, 34136 Trieste, Italy
| | - Dirk Dietzel
- Institute of Applied Physics, University of Giessen, 33492 Giessen, Germany
| | - Andre Schirmeisen
- Institute of Applied Physics, University of Giessen, 33492 Giessen, Germany
| | - Ernst Meyer
- Department of Physics, University of Basel, Klingelbergstr. 82, CH-4056 Basel, Switzerland
| | - Rémy Pawlak
- Department of Physics, University of Basel, Klingelbergstr. 82, CH-4056 Basel, Switzerland
| | - Thilo Glatzel
- Department of Physics, University of Basel, Klingelbergstr. 82, CH-4056 Basel, Switzerland
| | - Marcin Kisiel
- Department of Physics, University of Basel, Klingelbergstr. 82, CH-4056 Basel, Switzerland
| | - Shigeki Kawai
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1, Namiki, Tsukuba, Ibaraki 305-0044, Japan
| | - Nicola Manini
- Dipartimento di Fisica, Università degli Studi di Milano, via Celoria 16, 20133 Milano, Italy
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Brely L, Bosia F, Pugno NM. Emergence of the interplay between hierarchy and contact splitting in biological adhesion highlighted through a hierarchical shear lag model. SOFT MATTER 2018; 14:5509-5518. [PMID: 29923589 DOI: 10.1039/c8sm00507a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Contact unit size reduction is a widely studied mechanism as a means to improve adhesion in natural fibrillar systems, such as those observed in beetles or geckos. However, these animals also display complex structural features in the way the contact is subdivided in a hierarchical manner. Here, we study the influence of hierarchical fibrillar architectures on the load distribution over the contact elements of the adhesive system, and the corresponding delamination behaviour. We present an analytical model to derive the load distribution in a fibrillar system loaded in shear, including hierarchical splitting of contacts, i.e. a "hierarchical shear-lag" model that generalizes the well-known shear-lag model used in mechanics. The influence on the detachment process is investigated introducing a numerical procedure that allows the derivation of the maximum delamination force as a function of the considered geometry, including statistical variability of local adhesive energy. Our study suggests that contact splitting generates improved adhesion only in the ideal case of extremely compliant contacts. In real cases, to produce efficient adhesive performance, contact splitting needs to be coupled with hierarchical architectures to counterbalance high load concentrations resulting from contact unit size reduction, generating multiple delamination fronts and helping to avoid detrimental non-uniform load distributions. We show that these results can be summarized in a generalized adhesion scaling scheme for hierarchical structures, proving the beneficial effect of multiple hierarchical levels. The model can thus be used to predict the adhesive performance of hierarchical adhesive structures, as well as the mechanical behaviour of composite materials with hierarchical reinforcements.
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Affiliation(s)
- Lucas Brely
- Department of Physics and "Nanostructured Interfaces and Surfaces" Inter-Departmental Centre, Università di Torino, Via P. Giuria 1, 10125, Torino, Italy
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Genin GM, Shenoy VB, Peng G, Buehler MJ. Integrated Multiscale Biomaterials Experiment and Modeling. ACS Biomater Sci Eng 2017; 3:2628-2632. [PMID: 31157296 PMCID: PMC6544164 DOI: 10.1021/acsbiomaterials.7b00821] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The integration of modeling and experimentation is an integral component of all engineering design. Developing the technologies to achieve this represents a critical challenge in biomaterials because of the hierarchical structures that comprise them and the spectra of timescales upon which they operate. Progress in integrating modeling and experiment in biomaterials represents progress towards harnessing them for engineering application. We present here a summary of the state of the art, and outlooks for the field as a whole.
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Affiliation(s)
- Guy M Genin
- Department of Mechanical Engineering and Materials Science, 1 Brookings Drive, Washington University in St. Louis, St. Louis, MO 63130 United States
- NSF Science and Technology Center for Engineering Mechanobiology, 1 Brookings Drive, Washington University in St. Louis, St. Louis, MO 63130 United States
| | - Vivek B Shenoy
- Department of Materials Science and Engineering, University of Pennsylvania, 220 South 33rd Street, Philadelphia, PA 19104-6391 United States
- NSF Science and Technology Center for Engineering Mechanobiology, University of Pennsylvania, 220 South 33rd Street, Philadelphia, PA 19104-6391 United States
| | - Grace Peng
- National Institute of Biomedical Imaging and Bioengineering, 6707 Democracy Boulevard, Suite 202, Bethesda, MD 20892-5469 United States
| | - Markus J Buehler
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
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