Desiccation of a clay film: Cracking versus peeling

Abstract

We report a simulation study on competition between cracking and peeling, in a layer of clay on desiccation and how this is affected by the rate of drying, as well as the roughness of the substrate. The system is based on a simple 2-dimensional spring model. A vertical section through the layer with finite thickness is represented by a rectangular array of nodes connected by linear springs on a square lattice. The effect of reduction of the natural length of the springs, which mimics the drying is studied. Varying the strength of adhesion between sample and substrate and the rate of penetration of the drying front produces an interesting phase diagram, showing cross-over from peeling to cracking behavior. Changes in the number and width of cracks on varying the layer thickness is observed to reproduce experimental reports.

Electric-field-induced crack patterns: Experiments and simulation

“…We use an approach similar to [16,17], the difference being that a circular boundary is imposed and an additional force due to the electric field is incorporated.…”

“…In simulating the crack formation, we utilize the code for a 2-dimensional spring network, which was developed in [17] and used in [25]. It is modified here for application to a circular system, since the radial symmetry of the electric field must be implemented.…”

“…We show that typical crack patterns which depend on the field direction and strength [9,10] can be reproduced by a simple model using a spring network. This model has been applied earlier to explain crack patterns in composites [16] and peeling effects [17].…”

Crack formation in composites through a spring model

“…So each node takes up a new position after time δt, determined by vδt. This procedure is equivalent to a simplified form of Verlet's algorithm [10]. Here v is the instantaneous velocity of a particle calculated from the net force (i.e.…”

Observation and model of highly ordered wavy cracks due to coupling of in-plane stress and interface debonding in silica thin films

“…15 As mentioned above, the wavelength and the amplitude of the wavy path show little dependence on the film thickness, here it is suggested that the formation of the wavy cracks is more favored to be governed by the propagation velocity. It is noted that although the interaction of the interface debonding and the film crack has been discussed by several researches, [16][17][18] the effect of the propagation velocity on the interaction and coupling are not discussed. Here we try to illustrate this point based on the above experimental results.…”