Strength of adhesive contacts

Influence of contact geometry and material gradients

Valentin L. Popov, Roman Pohrt, Qiang Li

Research output: Contribution to journalArticle

40 Citations (Scopus)

Abstract

The strength of an adhesive contact between two bodies can strongly depend on the macroscopic and microscopic shape of the surfaces. In the past, the influence of roughness has been investigated thoroughly. However, even in the presence of perfectly smooth surfaces, geometry can come into play in form of the macroscopic shape of the contacting region. Here we present numerical and experimental results for contacts of rigid punches with flat but oddly shaped face contacting a soft, adhesive counterpart. When it is carefully pulled off, we find that in contrast to circular shapes, detachment occurs not instantaneously but detachment fronts start at pointed corners and travel inwards, until the final configuration is reached which for macroscopically isotropic shapes is almost circular. For elongated indenters, the final shape resembles the original one with rounded corners. We describe the influence of the shape of the stamp both experimentally and numerically. Numerical simulations are performed using a new formulation of the boundary element method for simulation of adhesive contacts suggested by Pohrt and Popov. It is based on a local, mesh dependent detachment criterion which is derived from the Griffith principle of balance of released elastic energy and the work of adhesion. The validation of the suggested method is made both by comparison with known analytical solutions and with experiments. The method is applied for simulating the detachment of flat-ended indenters with square, triangle or rectangular shape of cross-section as well as shapes with various kinds of faults and to “brushes”. The method is extended for describing power-law gradient media.

Original languageEnglish
Pages (from-to)308-325
Number of pages18
JournalFriction
Volume5
Issue number3
DOIs
Publication statusPublished - 1 Sep 2017

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Adhesives
Geometry
Brushes
Boundary element method
Adhesion
Surface roughness
Computer simulation
Experiments

Keywords

  • adhesion
  • boundary element method (BEM)
  • flat-ended indenters
  • gradient media

ASJC Scopus subject areas

  • Mechanical Engineering
  • Surfaces, Coatings and Films

Cite this

Strength of adhesive contacts : Influence of contact geometry and material gradients. / Popov, Valentin L.; Pohrt, Roman; Li, Qiang.

In: Friction, Vol. 5, No. 3, 01.09.2017, p. 308-325.

Research output: Contribution to journalArticle

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