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Junction formation during desiccation cracking K. B. Toga and B. Erdem Alaca*

Summary: Junction formation during desiccation cracking
K. B. Toga and B. Erdem Alaca*
Department of Mechanical Engineering, Koc University, Rumeli Feneri Yolu, 34450 Sariyer, Istanbul, Turkey
Received 18 November 2005; revised manuscript received 4 July 2006; published 9 August 2006
In order to provide a sound physical basis for the understanding of the formation of desiccation crack
networks, an experimental study is presented addressing junction formation. Focusing on junctions, basic
features of the network determining the final pattern, provides an elemental approach and imparts conceptual
clarity to the rather complicated problem of the evolution of crack patterns. Using coffee-water mixtures a clear
distinction between junction formation during nucleation and propagation is achieved. It is shown that for the
same drying suspension, one can switch from the well-known symmetric triple junctions that are unique to the
nucleation phase to propagation junctions that are purely dictated by the variations of the stress state. In the
latter case, one can even manipulate the path of a propagating crack in a deterministic fashion by changing the
stress state within the suspension. Clear microscopic evidence is provided for the formation of propagation
junctions, and material inhomogeneity is observed to be reflected by a broad distribution of angles, in stark
contrast to shrinkage cracks in homogeneous solid films.
DOI: 10.1103/PhysRevE.74.021405 PACS number s : 82.70.Kj, 62.20.Mk, 62.20.Dc
Pattern formation during desiccation cracking has been
extensively observed in laboratory settings using aqueous
suspensions of a variety of materials ranging from clay


Source: Alaca, B. Erdem - Department of Mechanical Engineering, Koc University


Collections: Engineering