On the Afferrante-Carbone theory of ultratough peeling

TL;DR

This paper discusses the Afferrante-Carbone theory of ultratough peeling, revealing conditions where peeling load can become arbitrarily large due to viscoelastic effects, suggesting a potential toughness enhancement beyond classical limits.

Contribution

It demonstrates that ultratough peeling occurs near critical speeds where elastic energy balances viscoelastic dissipation, expanding understanding of peeling mechanics.

Findings

Ultratough peeling occurs near critical speeds with balanced elastic and viscoelastic energies.

Toughness enhancement can surpass classical limits observed in large cracks.

Viscoelastic effects act as an on-off mechanism depending on peeling angle.

Abstract

In an elegant and interesting theory of ultratough peeling of an elastic tape from a viscoelastic substrate, Afferrante and Carbone (2016) find that, in contrast to the classic elastic Kendall's theory, there are conditions for which the load for steady state peeling could be arbitrarily large in steady state peeling, at low angles of peeling - what they call "ultratough" peeling. It is here shown in fact that this occurs near critical speeds where the elastic energy term of Kendall's equation is balanced by the viscoelastic dissipation. Surprisingly, this seems to lead to toughness enhancement higher than the limit value observed in a very large crack in a infinite viscoelastic body, possibly even considering a limit on the stress transmitted. Kendall's experiments in turn had considered viscoelastic tapes (rather than substrates), and his viscoelastic findinds seem to lead to a much simpler picture. The Afferrante-Carbone theory suggests the viscoelastic effect to be an on-off mechanism, since for large angles of peeling it is almost insignificant, while only below a certain threshold, this "ultratough" peeling seems to appear. Experimental and/or numerical verification would be most useful.