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Evaluation of the Curing of Adhesive Systems by Rheological and Thermal Testing
Published on: July 3, 2020
Oscillatory loading of a viscoelastic adhesive contact
1Department of Engineering, Cambridge University, Trumpington Street, Cambridge, CB2 1PZ, UK. jag@eng.cam.ac.uk
Journal of Colloid and Interface Science
|October 6, 2005
Summary
This study reveals that even slow loading of a viscoelastic material can yield higher pull-off forces than predicted by elastic models. Contact stiffness measurements also deviate significantly from expected elastic (JKR) values.
Area of Science:
- Adhesion science
- Viscoelasticity
- Contact mechanics
Background:
- Understanding the mechanical behavior of adhesive, viscoelastic materials under cyclic loading is crucial for various engineering applications.
- Existing models, such as the Johnson-Kendall-Roberts (JKR) theory, primarily address purely elastic contacts and may not fully capture viscoelastic effects.
- The Maugis-Dugdale model provides a framework for analyzing adhesive contact with a non-linear force-separation law.
Purpose of the Study:
- To investigate the loading-unloading behavior of a spherical probe on a viscoelastic specimen.
- To numerically integrate crack speed and apparent surface energy relationships for a linear 3-element viscoelastic solid.
- To analyze deviations from elastic predictions, specifically the pull-off force and contact stiffness.
Main Methods:
- Numerical integration of established relations between crack speed and apparent surface energy.
- Modeling the adhesive contact using a linear 3-element viscoelastic solid and a Maugis-Dugdale law.
- Simulating cyclic loading and unloading, including sinusoidal force modulation for stiffness determination.
Main Results:
- The pull-off force was found to be significantly greater than the elastic (JKR) value, even under near-elastic loading conditions.
- During unloading with sinusoidal force modulation, the contact radius showed minimal change.
- Measured contact stiffness closely approximated that of a rigid flat punch, deviating from the predicted JKR stiffness.
Conclusions:
- Viscoelasticity significantly influences adhesion and contact mechanics, leading to higher pull-off forces than predicted by purely elastic models.
- Standard methods for measuring contact stiffness in elastic systems may be inadequate for viscoelastic materials.
- The findings highlight the importance of considering viscoelastic properties in adhesion studies and contact mechanics modeling.
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