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Spontaneous formation and morphology of telephone cord blisters in thin films: The Ω formulae

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journal contribution
posted on 14.06.2019, 08:44 by Bo Yuan, Christopher Harvey, Rachel Thomson, Gary Critchlow, David S. Rickerby, Simon Wang
Telephone cord blisters (TCBs) are frequently observed in film/substrate material systems. They nucleate and propagate forward with wavy boundaries between the film and the substrate. The current study views the problem from a completely new angle: It is discovered that the spontaneous formation and morphology of TCBs in thin films under biaxial compressive residual stresses can be accurately explained and determined by assuming the existence of a pocket of energy concentration (PEC) instead of the existence of a separation of critical size. For the first time, completely-analytical formulae—the ‘Ω formulae’—are derived for the two local morphology parameters of TCBs of any shape, that is, width and height, and for the two global morphology parameters of TCBs of sinusoidal shape, that is, the wavelength and transverse amplitude. Mechanical conditions are also given for the first time for the formation of TCBs. Predictions for the four morphology parameters of the developed theory agree very well with extensive experimental results. In addition, by reversing the calculation, the residual stress and the film/substrate interface fracture toughness are also accurately determined from measurements of the TCB morphology parameters.

History

School

  • Aeronautical, Automotive, Chemical and Materials Engineering

Department

  • Aeronautical and Automotive Engineering
  • Materials

Published in

Composite Structures

Volume

225

Citation

YUAN, B. ... et al, 2019. Spontaneous formation and morphology of telephone cord blisters in thin films: The Ω formulae. Composite Structures, 225, Article 111108.

Publisher

© Elsevier

Version

AM (Accepted Manuscript)

Publisher statement

This paper was accepted for publication in the journal Composite Structures and the definitive published version is available at https://doi.org/10.1016/j.compstruct.2019.111108.

Acceptance date

31/05/2019

Publication date

2019-06-01

Copyright date

2019

ISSN

0263-8223

Language

en

Article number

111108

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