Enhancing strength and toughness of adhesive joints via micro-structured mechanical interlocking

Alexander Hamilton, Yang Xu* (Corresponding Author), Mehmet Kartal, Nikolaj Gadegaard, Daniel M Mulvihill* (Corresponding Author)

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

14 Citations (Scopus)
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The potential to improve the mechanical properties of adhesive joints via micro-structured interlocking features is investigated. The micro-structured surfaces were fabricated in polycarbonate via injection moulding from a master template. The specimens were then bonded in an interlocking configuration to form single lap joints and tested to failure in tension. Planar untreated (i.e. unabraded) and planar roughened (i.e. abraded) samples were also tested to provide benchmarks. Compared to the planar roughened case, results show that micro-structuring the interface can yield up to a 95.9% increase in strength and up to 162% increase in work to failure. Increases in strength and work to failure beyond the planar roughened level are attributed to mechanical interlocking of
features. As deformation proceeds, progressive bending of each pair of interlocking features develops an increasing resistive load which allows the total load to significantly exceed that of the planar roughened case. Work to failure is increased via a combination of increased maximum force, increased displacement enabled by microfeature bending and a more torturous crack path. Low clearances between interlocking features were found to be favourable for mechanical properties owing to reduced bending stiffness of the repeating periodic unit at the interface.
Original languageEnglish
Article number102775
Number of pages10
JournalInternational Journal of Adhesion and Adhesives
Early online date13 Nov 2020
Publication statusPublished - 1 Mar 2021

Bibliographical note

The authors would like to acknowledge the support of the Leverhulme Trust for supporting the work under project grant “Fundamental Mechanical Behaviour of Nano and Micro Structured Interfaces” (RPG-2017-353) and the EPSRC for providing an EPSRC-DTG PhD studentship (EP/N509668/1) for the first author. Personnel at the James Watt Nanofabrication Centre (JWNC) at the University of Glasgow are also thanked for their invaluable technical support.


  • adhesion
  • micro-structured surface
  • surface texturing
  • mechanical interlocking
  • lap joint
  • Strength
  • toughness


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