Extremely Curved Cracks

The word "extreme" seems to be "trending" a lot these days, see the recent discussions on the new journal Extreme Mechanics Letters.

My collaborator Ruben Sevilla at Swansea and I were interested in very curved crack paths that develop in nature and have been replicated experimentally in thin films attached to elastic substrates.

We called these patterns "extremely curved". We then thought of a combination of NURBS (used in CAD software and recently in isogeometric analysis) and meshfree methods as a tool to describe these cracks which would be very complicated or impossible to describe in standard finite element software.

We applied it to a variety of examples, with very eye-catching results in some cases! One of them is the spiral crack, explained in Xia ZC, Hutchinson JW (2000) Crack patterns in thin films. Journal of the Mechanics and Physics of Solids 48(6):1107–1131.

Another example are wavy cracks (and network of wavy cracks) in drying colloidal films.

Whilst the paper is numerical and still needs the "physics" behind the cracking, we think that this can help develop more ideas in exploiting crack patterns (see recent paper in Nature Communications by the Barthelat group on overcoming the brittleness of glass), or to explain curved cracking in natural systems (see recent paper by Pugno and Buehler on the Mechanics of fragmentation of crocodile skin and other thin films).

We welcome collaborations with other mechanicians (and also non-mechanicians) 

The paper (accepted in Computational Mechanics) is at 

http://link.springer.com/article/10.1007/s00466-014-1067-4