We compare experimental observations of a slow interfacial crack propagation along an heterogeneous interface to numerical simulations using a soft-clamped fiber bundle model.
The model consists of a planar set of brittle fibers between a deformable elastic half-space and a rigid plate with a square root shape that imposes a non-linear displacement around the process zone.
Their model was a development of the soft clamp fiber bundle model [25, 26] first introduced by Batrouni et al. Even though the characteristics of the crack front that was created in the soft clamp fiber bundle model through the introduction of a linear gradient matched the experimental observations well, it cannot be ignored that the crack front was generated in a very different way in the experiment.
Notably the front morphology in these models does not display a cross-over length scale with two different roughness exponents above and below it.
Such a cross-over was observed experimentally in 2010 by Santucci et al. They found that the in-plane fractures also had a scale-dependent roughness exponent. Attempts to model the behavior of the in-plane fracture process had a long time resulted in only the large scale roughness exponent [16, 17], or the small scale roughness exponent in the context of a stress-weighted percolation .
It consists of two transparent welded plexiglas (PMMA - poly methyl methacrylate) plates [e.g., 8, 11, 28, 29].
Disorder in the strength of the interface between the two plates is introduced by sandblasting using glass beads of variable diameters (180–300 μm), the opposite surfaces of the two plates that are to be welded together.