George G. Adams - Academia.edu (original) (raw)

Papers by George G. Adams

Research paper thumbnail of The Mechanics of Adhesion: Current and Future Research Trends

STLE/ASME 2008 International Joint Tribology Conference, 2008

As the size of the contact region between two bodies decreases to the micro-and nano-scale, the e... more As the size of the contact region between two bodies decreases to the micro-and nano-scale, the effect of adhesion becomes increasingly important. As introductory remarks to a panel discussion on this topic, we briefly review recent research in the mechanics of adhesion and discuss future research needs. Attention is focused on adhesion with plastic deformation, molecular dynamics simulations, and multi-scale effects.

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Research paper thumbnail of The Mechanics of Adhesion: A Tutorial

STLE/ASME 2008 International Joint Tribology Conference, 2008

As the size of the contact region between two bodies decreases to the micro-and nano-scales, the ... more As the size of the contact region between two bodies decreases to the micro-and nano-scales, the effect of adhesion becomes increasingly important. In this tutorial, we review fundamental concepts of the mechanics of adhesion. Attention is placed on the contact of elastic bodies in which the shapes of the contacting bodies are locally spherical. We also discuss the use of spherical contact theory to model the adhesive contact of an asperity with a flat as part of a multi-asperity contact model.

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Research paper thumbnail of Contacts Considering Adhesion

Encyclopedia of Tribology, 2013

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Research paper thumbnail of Deformation of Bowed Silicon Wafers Due to Applied Pressure and Adhesion

Part B: Magnetic Storage Tribology; Manufacturing/Metalworking Tribology; Nanotribology; Engineered Surfaces; Biotribology; Emerging Technologies; Special Symposia on Contact Mechanics; Special Symposium on Nanotribology, 2006

One potential method to accomplish high-rate nanomanufacturing is to develop processes which allo... more One potential method to accomplish high-rate nanomanufacturing is to develop processes which allow for rapid transfer of nano-scaled devices from a template to a device wafer [1]. In order to accomplish this transfer, the device wafer must make intimate contact with the template. A similar situation exists in wafer bonding, except that in that case the two wafers remain in bonded contact due to surface energy even after the applied pressure is removed. We need to maintain intimate contact during transfer, while allowing for easy separation ...

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Research paper thumbnail of Postbuckling of an elastic plate in a rigid channel

International Journal of Mechanical Sciences, 1986

Abstract The postbuckling of a thin, elastic plate in a frictional channel of rigid parallel wall... more Abstract The postbuckling of a thin, elastic plate in a frictional channel of rigid parallel walls is studied. Different modes of contact between the plate and the channel walls are identified and modelled using the theory of the elastica. Example results are presented which illustrate the sequence of deflections through which the postbuckled plate passes. Loading on the plate is also studied, and it is found that narrow channels arrest the initial buckling of the plate but permit a second stage of collapse at higher force levels. This work would have ...

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Research paper thumbnail of Concepts in Contact Recording: Presented at the 1991 STLE/ASME Tribology Conference, October 13-16, 1991, St. Louis, Missouri

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Research paper thumbnail of Information Storage and Processing Systems, 1998: 9th International Symposium on Information Storage and Processing Systems, 1998: Presented at the 1998 ASME International Mechanical Engineering Congress and Exposition: November 15-20, 1998, Anaheim, California

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Research paper thumbnail of Contact Mechanics--friction: Modeling and Experiment: Presented at 2003 STLE/ASME Joint International Tribology Conference: October 26-29, 2003, Ponte Vedra Beach, Florida

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Research paper thumbnail of SMA actuators applied to biomimetic underwater robots

Neurotechnology for biomimetic robots, 2001

The work on Ni-Ti (nickel-titanium) shape memory alloy actuators presented here arises from the n... more The work on Ni-Ti (nickel-titanium) shape memory alloy actuators presented here arises from the need for a biomimetic linear actuator, in the context of building a biomimetic ambulatory underwater robot. The model animal used is the American lobster Homarus americanus, chosen due to its behavioral robustness in dealing with the complex benthic habitat identified as the target environment for the vehicle. As reported elsewhere in this book Chapter 12, the biomimetic aspect of our effort consists of not only reverse kinematic ...

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Research paper thumbnail of Asperity-Based Models of Micro-Scale Friction

World Tribology Congress III, Volume 1, 2005

As surfaces become smoother and loading forces decrease in applications such as MEMS, NEMS, and m... more As surfaces become smoother and loading forces decrease in applications such as MEMS, NEMS, and magnetic recording devices, the size and number of the asperity contacts which comprise the real contact area continues to decrease. The tangential force which is measured between two sliding bodies is the combined result of friction forces which are present in a very large number of nano and micro scale asperity contacts. Recent experiments as well as modeling have shown considerable scale-dependence and ...

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Research paper thumbnail of Dynamic Modeling and Hydrodynamic Performance of Biomimetic Underwater Robot Locomotion

Autonomous Robots, 2002

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Research paper thumbnail of Large deflection analysis of a biomimetic lobster antenna due to contact and flow

Résumé/Abstract Lobsters use their antennae to navigate among obstacles along the ocean floor Eff... more Résumé/Abstract Lobsters use their antennae to navigate among obstacles along the ocean floor Effective ambulation requires that the lobster, or a biomimetic lobster robot whose behavior is patterned after a real lobster must distinguish between antenna bending due to contact and bending due to flow. The analysis presented here shows that the key feature appears to be the taper of the antennae. The curvature of a tapered antenna due to an end-load is nearly constant whereas the curvature distribution due to flow is nearly a quadratic ...

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Research paper thumbnail of Dilatational and shear waves induced by the frictional sliding of two elastic half-spaces

International Journal of Engineering Science, Jul 1, 2001

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Research paper thumbnail of Method of integrating a single nanowire into a nanocircuit

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Research paper thumbnail of Contact Evolution in a Micromechanical Switch

An AFM-based test station has been established for rapid mechanical and electrical characterizati... more An AFM-based test station has been established for rapid mechanical and electrical characterization of contacts in a micromechanical switch. A wide contact force range is accessible, from nN to mN, determined by the mechanical properties of the microfabricated contact test cantilevers. During testing the contact force, deformation, and contact adhesion are measured. Periodic observations of material transfer are made. The cycling rate can reach 200 kHz.

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Research paper thumbnail of System and method for integrating a single nanowire into a nanocircuit

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Research paper thumbnail of Large Deflection Analysis of a Biomimetic Lobster Robot Antenna due to Contact and Flow

Journal of Applied Mechanics, Nov 1, 2001

Résumé/Abstract Lobsters use their antennae to navigate among obstacles along the ocean floor Eff... more Résumé/Abstract Lobsters use their antennae to navigate among obstacles along the ocean floor Effective ambulation requires that the lobster, or a biomimetic lobster robot whose behavior is patterned after a real lobster must distinguish between antenna bending due to contact and bending due to flow. The analysis presented here shows that the key feature appears to be the taper of the antennae. The curvature of a tapered antenna due to an end-load is nearly constant whereas the curvature distribution due to flow is nearly a quadratic ...

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Research paper thumbnail of Adhesion-Induced Tangential Driving Force Acting on a Spherical Particle Lying on a Sinusoidal Surface

The Journal of Adhesion, 2015

ABSTRACT A spherical particle lies on a sinusoidal surface under the force of adhesion. Both the ... more ABSTRACT A spherical particle lies on a sinusoidal surface under the force of adhesion. Both the sphere and the wavy body are considered to be elastic. Because the radius of curvature of the surface varies with position, the composite radius of curvature of the sphere and the surface also varies with position. The total energy of the system, which includes the adhesion energy, decreases as the composite radius of curvature increases. As a consequence it is energetically favorable for the sphere to move away from the surface peaks and toward the valleys. The existence of this adhesion-energy-induced driving force demonstrated theoretically and its value is determined for a range of sphere positions. Linear theory predicts that it can be as large as about 2% of the pull-off force. The inclusion of non-linear effects would be expected to increase this driving force.

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Research paper thumbnail of Stick, partial slip and sliding in the plane strain micro contact of two elastic bodies

Royal Society open science, 2014

The plane strain problem of a curved elastic body pressed against an elastic half-space is consid... more The plane strain problem of a curved elastic body pressed against an elastic half-space is considered. The effect of adhesion is included through the use of surface energy in a manner similar to the well-known JKR theory for spherical contacts. The compressive normal force is held constant while a tangential force is gradually increased from zero. The contact is characterized by complete stick up to a critical value of the tangential force when there is a transition either directly to complete sliding or to a partial slip state in which a central stick region is surrounded by two slip regions. In the latter case, at a finite value of the stick zone width, a second critical condition exists at which there is a transition from partial slip to complete sliding. This behaviour is determined for a range of dimensionless values of the work of adhesion, the assumed constant shear stress during slip/sliding and the initial compressive load.

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Research paper thumbnail of The Sliding and Rolling of a Cylinder at the Nano-Scale

ASME/STLE 2004 International Joint Tribology Conference, Parts A and B, 2004

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Research paper thumbnail of The Mechanics of Adhesion: Current and Future Research Trends

STLE/ASME 2008 International Joint Tribology Conference, 2008

As the size of the contact region between two bodies decreases to the micro-and nano-scale, the e... more As the size of the contact region between two bodies decreases to the micro-and nano-scale, the effect of adhesion becomes increasingly important. As introductory remarks to a panel discussion on this topic, we briefly review recent research in the mechanics of adhesion and discuss future research needs. Attention is focused on adhesion with plastic deformation, molecular dynamics simulations, and multi-scale effects.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of The Mechanics of Adhesion: A Tutorial

STLE/ASME 2008 International Joint Tribology Conference, 2008

As the size of the contact region between two bodies decreases to the micro-and nano-scales, the ... more As the size of the contact region between two bodies decreases to the micro-and nano-scales, the effect of adhesion becomes increasingly important. In this tutorial, we review fundamental concepts of the mechanics of adhesion. Attention is placed on the contact of elastic bodies in which the shapes of the contacting bodies are locally spherical. We also discuss the use of spherical contact theory to model the adhesive contact of an asperity with a flat as part of a multi-asperity contact model.

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Research paper thumbnail of Contacts Considering Adhesion

Encyclopedia of Tribology, 2013

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Research paper thumbnail of Deformation of Bowed Silicon Wafers Due to Applied Pressure and Adhesion

Part B: Magnetic Storage Tribology; Manufacturing/Metalworking Tribology; Nanotribology; Engineered Surfaces; Biotribology; Emerging Technologies; Special Symposia on Contact Mechanics; Special Symposium on Nanotribology, 2006

One potential method to accomplish high-rate nanomanufacturing is to develop processes which allo... more One potential method to accomplish high-rate nanomanufacturing is to develop processes which allow for rapid transfer of nano-scaled devices from a template to a device wafer [1]. In order to accomplish this transfer, the device wafer must make intimate contact with the template. A similar situation exists in wafer bonding, except that in that case the two wafers remain in bonded contact due to surface energy even after the applied pressure is removed. We need to maintain intimate contact during transfer, while allowing for easy separation ...

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Research paper thumbnail of Postbuckling of an elastic plate in a rigid channel

International Journal of Mechanical Sciences, 1986

Abstract The postbuckling of a thin, elastic plate in a frictional channel of rigid parallel wall... more Abstract The postbuckling of a thin, elastic plate in a frictional channel of rigid parallel walls is studied. Different modes of contact between the plate and the channel walls are identified and modelled using the theory of the elastica. Example results are presented which illustrate the sequence of deflections through which the postbuckled plate passes. Loading on the plate is also studied, and it is found that narrow channels arrest the initial buckling of the plate but permit a second stage of collapse at higher force levels. This work would have ...

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Research paper thumbnail of Concepts in Contact Recording: Presented at the 1991 STLE/ASME Tribology Conference, October 13-16, 1991, St. Louis, Missouri

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Information Storage and Processing Systems, 1998: 9th International Symposium on Information Storage and Processing Systems, 1998: Presented at the 1998 ASME International Mechanical Engineering Congress and Exposition: November 15-20, 1998, Anaheim, California

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Contact Mechanics--friction: Modeling and Experiment: Presented at 2003 STLE/ASME Joint International Tribology Conference: October 26-29, 2003, Ponte Vedra Beach, Florida

Bookmarks Related papers MentionsView impact

Research paper thumbnail of SMA actuators applied to biomimetic underwater robots

Neurotechnology for biomimetic robots, 2001

The work on Ni-Ti (nickel-titanium) shape memory alloy actuators presented here arises from the n... more The work on Ni-Ti (nickel-titanium) shape memory alloy actuators presented here arises from the need for a biomimetic linear actuator, in the context of building a biomimetic ambulatory underwater robot. The model animal used is the American lobster Homarus americanus, chosen due to its behavioral robustness in dealing with the complex benthic habitat identified as the target environment for the vehicle. As reported elsewhere in this book Chapter 12, the biomimetic aspect of our effort consists of not only reverse kinematic ...

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Asperity-Based Models of Micro-Scale Friction

World Tribology Congress III, Volume 1, 2005

As surfaces become smoother and loading forces decrease in applications such as MEMS, NEMS, and m... more As surfaces become smoother and loading forces decrease in applications such as MEMS, NEMS, and magnetic recording devices, the size and number of the asperity contacts which comprise the real contact area continues to decrease. The tangential force which is measured between two sliding bodies is the combined result of friction forces which are present in a very large number of nano and micro scale asperity contacts. Recent experiments as well as modeling have shown considerable scale-dependence and ...

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Research paper thumbnail of Dynamic Modeling and Hydrodynamic Performance of Biomimetic Underwater Robot Locomotion

Autonomous Robots, 2002

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Research paper thumbnail of Large deflection analysis of a biomimetic lobster antenna due to contact and flow

Résumé/Abstract Lobsters use their antennae to navigate among obstacles along the ocean floor Eff... more Résumé/Abstract Lobsters use their antennae to navigate among obstacles along the ocean floor Effective ambulation requires that the lobster, or a biomimetic lobster robot whose behavior is patterned after a real lobster must distinguish between antenna bending due to contact and bending due to flow. The analysis presented here shows that the key feature appears to be the taper of the antennae. The curvature of a tapered antenna due to an end-load is nearly constant whereas the curvature distribution due to flow is nearly a quadratic ...

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Research paper thumbnail of Dilatational and shear waves induced by the frictional sliding of two elastic half-spaces

International Journal of Engineering Science, Jul 1, 2001

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Research paper thumbnail of Method of integrating a single nanowire into a nanocircuit

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Contact Evolution in a Micromechanical Switch

An AFM-based test station has been established for rapid mechanical and electrical characterizati... more An AFM-based test station has been established for rapid mechanical and electrical characterization of contacts in a micromechanical switch. A wide contact force range is accessible, from nN to mN, determined by the mechanical properties of the microfabricated contact test cantilevers. During testing the contact force, deformation, and contact adhesion are measured. Periodic observations of material transfer are made. The cycling rate can reach 200 kHz.

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Research paper thumbnail of System and method for integrating a single nanowire into a nanocircuit

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Large Deflection Analysis of a Biomimetic Lobster Robot Antenna due to Contact and Flow

Journal of Applied Mechanics, Nov 1, 2001

Résumé/Abstract Lobsters use their antennae to navigate among obstacles along the ocean floor Eff... more Résumé/Abstract Lobsters use their antennae to navigate among obstacles along the ocean floor Effective ambulation requires that the lobster, or a biomimetic lobster robot whose behavior is patterned after a real lobster must distinguish between antenna bending due to contact and bending due to flow. The analysis presented here shows that the key feature appears to be the taper of the antennae. The curvature of a tapered antenna due to an end-load is nearly constant whereas the curvature distribution due to flow is nearly a quadratic ...

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Adhesion-Induced Tangential Driving Force Acting on a Spherical Particle Lying on a Sinusoidal Surface

The Journal of Adhesion, 2015

ABSTRACT A spherical particle lies on a sinusoidal surface under the force of adhesion. Both the ... more ABSTRACT A spherical particle lies on a sinusoidal surface under the force of adhesion. Both the sphere and the wavy body are considered to be elastic. Because the radius of curvature of the surface varies with position, the composite radius of curvature of the sphere and the surface also varies with position. The total energy of the system, which includes the adhesion energy, decreases as the composite radius of curvature increases. As a consequence it is energetically favorable for the sphere to move away from the surface peaks and toward the valleys. The existence of this adhesion-energy-induced driving force demonstrated theoretically and its value is determined for a range of sphere positions. Linear theory predicts that it can be as large as about 2% of the pull-off force. The inclusion of non-linear effects would be expected to increase this driving force.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Stick, partial slip and sliding in the plane strain micro contact of two elastic bodies

Royal Society open science, 2014

The plane strain problem of a curved elastic body pressed against an elastic half-space is consid... more The plane strain problem of a curved elastic body pressed against an elastic half-space is considered. The effect of adhesion is included through the use of surface energy in a manner similar to the well-known JKR theory for spherical contacts. The compressive normal force is held constant while a tangential force is gradually increased from zero. The contact is characterized by complete stick up to a critical value of the tangential force when there is a transition either directly to complete sliding or to a partial slip state in which a central stick region is surrounded by two slip regions. In the latter case, at a finite value of the stick zone width, a second critical condition exists at which there is a transition from partial slip to complete sliding. This behaviour is determined for a range of dimensionless values of the work of adhesion, the assumed constant shear stress during slip/sliding and the initial compressive load.

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Research paper thumbnail of The Sliding and Rolling of a Cylinder at the Nano-Scale

ASME/STLE 2004 International Joint Tribology Conference, Parts A and B, 2004

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