Suction-controlled detachment of mushroom-shaped adhesive structures

Marcela Areyano*, Jamie A. Booth, Dane Brouwer, Luke F. Gockowski, Megan T. Valentine, Robert M. McMeeking

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Experimental evidence suggests that suction may play a role in the attachment strength of mushroom-tipped adhesive structures, but the system parameters which control this effect are not well established. A fracture mechanics-based model is introduced to determine the critical stress for defect propagation at the interface in the presence of trapped air. These results are compared with an experimental investigation of millimeter-scale elastomeric structures. These structures are found to exhibit a greater increase in strength due to suction than is typical in the literature, as they have a large tip diameter relative to the stalk. The model additionally provides insight into differences in expected behavior across the design space of mushroom-shaped structures. For example, the model reveals that the suction contribution is length-scale dependent. It is enhanced for larger structures due to increased volume change, and thus the attainment of lower pressures, inside of the defect. This scaling effect is shown to be less pronounced if the tip is made wider relative to the stalk. An asymptotic result is also provided in the limit that the defect is far outside of the stalk, showing that the critical stress is lower by a factor of 1/2 than the result often used in the literature to estimate the effect of suction. This discrepancy arises as the latter considers only the balance of remote stress and pressure inside the defect and neglects the influence of compressive tractions outside of the defect.

Original languageEnglish
Article number031017
Number of pages8
JournalJournal of Applied Mechanics, Transactions ASME
Volume88
Issue number3
Early online date6 Jan 2021
DOIs
Publication statusPublished - Mar 2021

Keywords

  • Energy release rate and delamination
  • Mechanical properties of materials
  • Structures

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