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6 results on '"Adhesive hysteresis"'

1. Adhesive contact mechanics of bio-inspired pillars: Exploring hysteresis and detachment modes.

Author

Violano, G., Dibitonto, S., and Afferrante, L.

Subjects
*VAN der Waals forces, *CRACK propagation (Fracture mechanics), *FINITE element method, *SURFACE texture, *ADHESIVES
Abstract

Engineering technologies frequently draw inspiration from nature, as exemplified in bio-inspired adhesive surfaces. These surfaces present textures adorned by pillars, mimicking the topography found on the pads of certain animals renowned for their exceptional adhesive capabilities. The adhesive response is strongly influenced by the morphology of these pillars. In typical existing models, perfect bonding conditions are assumed between the pillar and the countersurface, and solely the detachment process of the pillar from the countersurface is investigated. The proposed model, based on the assumption that interactions at the interface are governed by van der Waals forces modeled by the Lennard-Jones potential law, enables the examination of the entire approach and retraction cycle, tracking the movement of the pillar towards and away from the countersurface. Our findings reveal that adhesive contact mechanics is primarily influenced by the geometry of the pillar and the potential presence of interfacial 'defects', which in turn affect the distribution of contact pressure. Furthermore, we show that the detachment process may simultaneously involve various modes of separation, such as crack propagation from outer edge, crack propagation from inner defects, and uniform decohesion. This suggests that existing theoretical models alone cannot fully elucidate the complexity of detachment phenomena. Additionally, we anticipate the occurrence of hysteretic losses during the approach-retraction cycle, attributed to pull-in and pull-off contact jumps. Adhesive hysteresis is a phenomenon consistently observed in experiments but frequently overlooked in existing models. [ABSTRACT FROM AUTHOR]

Published
2024
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2. On the interplay between roughness and viscoelasticity in adhesive hysteresis

Author

Universitat Politècnica de Catalunya. Departament d'Enginyeria Minera, Industrial i TIC, Universitat Politècnica de Catalunya. RIIS - Grup de Recerca en Recursos i Indústries Intel·ligents i Sostenibles, Pérez Rafols, Francisco, van Dokkum, Jan Steven, Nicola, Lucia, Universitat Politècnica de Catalunya. Departament d'Enginyeria Minera, Industrial i TIC, Universitat Politècnica de Catalunya. RIIS - Grup de Recerca en Recursos i Indústries Intel·ligents i Sostenibles, Pérez Rafols, Francisco, van Dokkum, Jan Steven, and Nicola, Lucia

Abstract

Viscoelasticity and roughness are among the possible causes of the adhesive hysteresis displayed by soft contacts. Viscoelasticity causes an increased effective work of adhesion due to stiffening of the contact, while roughness is responsible for elastic instabilities. Herein, we explore the interplay between viscoelasticity and roughness by simulating in two dimensions the retraction of a rigid cylinder, with wavy surface profile, from a viscoelastic half-space. The wave amplitude and length are varied to induce instabilities in the load–to–area response, while the retraction velocity is increased to promote viscoelasticity. Results show that, in the regime where viscoelasticity is confined to the edges of the wavy contact, the contributions of viscoelasticity and waviness to adhesive hysteresis are nearly independent and additive. At low retraction rates, the instabilities in the load-area curve typical of rough elastic contacts are suppressed by viscoelasticity: the contact stiffens to promote a stable decrease of the contact area with load. This occurs with a minimal change in work of adhesion. However, when the instantaneous limit is met at high retraction rates, mechanical instabilities appear., LN acknowledges funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement no. 681813)., Peer Reviewed, Postprint (published version)

Published
2023

3. On the interplay between roughness and viscoelasticity in adhesive hysteresis

Author

Pérez-Ràfols, Francesc (author), van Dokkum, J.S. (author), Nicola, L. (author), Pérez-Ràfols, Francesc (author), van Dokkum, J.S. (author), and Nicola, L. (author)

Abstract

Viscoelasticity and roughness are among the possible causes of the adhesive hysteresis displayed by soft contacts. Viscoelasticity causes an increased effective work of adhesion due to stiffening of the contact, while roughness is responsible for elastic instabilities. Herein, we explore the interplay between viscoelasticity and roughness by simulating in two dimensions the retraction of a rigid cylinder, with wavy surface profile, from a viscoelastic half-space. The wave amplitude and length are varied to induce instabilities in the load–to–area response, while the retraction velocity is increased to promote viscoelasticity. Results show that, in the regime where viscoelasticity is confined to the edges of the wavy contact, the contributions of viscoelasticity and waviness to adhesive hysteresis are nearly independent and additive. At low retraction rates, the instabilities in the load-area curve typical of rough elastic contacts are suppressed by viscoelasticity: the contact stiffens to promote a stable decrease of the contact area with load. This occurs with a minimal change in work of adhesion. However, when the instantaneous limit is met at high retraction rates, mechanical instabilities appear., Team Erik Offerman, Team Marcel Sluiter

Published
2023
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5. On the interplay between roughness and viscoelasticity in adhesive hysteresis

Author

Francesc Pérez-Ràfols, Jan Steven Van Dokkum, Lucia Nicola, Universitat Politècnica de Catalunya. Departament d'Enginyeria Minera, Industrial i TIC, and Universitat Politècnica de Catalunya. RIIS - Grup de Recerca en Recursos i Indústries Intel·ligents i Sostenibles

Subjects
Viscoelastic materials, Adhesió, Adhesion and adhesives, Mechanical Engineering, Viscoelasticitat, Condensed Matter Physics, Viscoelastic material, Contact mechanics, Enginyeria mecànica [Àrees temàtiques de la UPC], Surface roughness, Mechanics of Materials, Adhesive hysteresis, Adhesion, Rugositat superficial, Mecànica de contacte
Abstract

Viscoelasticity and roughness are among the possible causes of the adhesive hysteresis displayed by soft contacts. Viscoelasticity causes an increased effective work of adhesion due to stiffening of the contact, while roughness is responsible for elastic instabilities. Herein, we explore the interplay between viscoelasticity and roughness by simulating in two dimensions the retraction of a rigid cylinder, with wavy surface profile, from a viscoelastic half-space. The wave amplitude and length are varied to induce instabilities in the load–to–area response, while the retraction velocity is increased to promote viscoelasticity. Results show that, in the regime where viscoelasticity is confined to the edges of the wavy contact, the contributions of viscoelasticity and waviness to adhesive hysteresis are nearly independent and additive. At low retraction rates, the instabilities in the load-area curve typical of rough elastic contacts are suppressed by viscoelasticity: the contact stiffens to promote a stable decrease of the contact area with load. This occurs with a minimal change in work of adhesion. However, when the instantaneous limit is met at high retraction rates, mechanical instabilities appear. LN acknowledges funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement no. 681813).

Published
2023

6. On the interplay between roughness and viscoelasticity in adhesive hysteresis.

Author

Pérez-Ràfols, Francesc, Van Dokkum, Jan Steven, and Nicola, Lucia

Subjects
*HYSTERESIS, *VISCOELASTICITY, *VISCOELASTIC materials, *CONTACT mechanics
Abstract

Viscoelasticity and roughness are among the possible causes of the adhesive hysteresis displayed by soft contacts. Viscoelasticity causes an increased effective work of adhesion due to stiffening of the contact, while roughness is responsible for elastic instabilities. Herein, we explore the interplay between viscoelasticity and roughness by simulating in two dimensions the retraction of a rigid cylinder, with wavy surface profile, from a viscoelastic half-space. The wave amplitude and length are varied to induce instabilities in the load–to–area response, while the retraction velocity is increased to promote viscoelasticity. Results show that, in the regime where viscoelasticity is confined to the edges of the wavy contact, the contributions of viscoelasticity and waviness to adhesive hysteresis are nearly independent and additive. At low retraction rates, the instabilities in the load-area curve typical of rough elastic contacts are suppressed by viscoelasticity: the contact stiffens to promote a stable decrease of the contact area with load. This occurs with a minimal change in work of adhesion. However, when the instantaneous limit is met at high retraction rates, mechanical instabilities appear. [ABSTRACT FROM AUTHOR]

Published
2023
Full Text
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