Soft-Clamp Fiber Bundle Model and Interfacial Crack Propagation: Comparison Using a Non-linear Imposed Displacement

Abstract

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. The non-linear square-root rigid shape combined with the long range elastic interactions is shown to provide more realistic displacement and stress fields around the crack tip in the process zone and thereby significantly improving the predictions of the model. Experiments and model are shown to share a similar self-affine roughening of the crack front both at small and large scales and a similar distribution of the local crack front velocity. Numerical predictions of the Family-Viscek scaling for both regimes are discussed together with the local velocity distribution of the fracture front.

Avalanches and extreme value statistics in interfacial crackling dynamics

“…Therefore, our results suggest that different approaches may be needed to fully describe the intermittent crack front dynamics, as for its complex selfaffine morphology [45,47,60]. While at large scales, the long-range elastic line model appears very successful, different approaches such as a percolation-like model [52,53] or thermally activated processes [61][62][63] could be more relevant to describe material failure at the local scale of the heterogeneities.…”

“…However, we could also show that such a model fails to reproduce the power-law distribution of the maximum amplitude of avalanches at fixed duration, which may be the signature of the fat-tail power-law statistics of the local crack front velocity. A different approach describing material failure as a correlated percolation process considering crack coalescence [52,53] could lead to such largely power-law distributed local velocity of the crack front [12,14,49]. Therefore, our results suggest that different approaches may be needed to fully describe the intermittent crack front dynamics, as for its complex selfaffine morphology [45,47,60].…”

“…This is not captured by the interfacial model which gives an exponential tail. Therefore, it can question the validity of the elastic line approach to describe the crack front dynamics at small scales close to the disorder, for which a percolation-like approach [52,53] might be more relevant.…”

Energy Partitioning During Subcritical Mode I Crack Propagation Through a Heterogeneous Interface

“…Model of the interfacial fracture crack propagation between two PMMA plates of thickness H and h . corresponds to the average front position (from ; Stormo et al, ).…”

“…Velocity variations of the rupture front are generally observed when detailed imaging of the rupture is obtained (typically in analog experiments; e.g., Måløy et al, ). These fluctuations of the rupture velocity are explained by the local pinning and depinning on asperities even if the macroscopic average rupture front velocity is low (Måløy & Schmittbuhl, ; Måløy et al, ; Stormo et al, ). During such slow subcritical ruptures, the experimentally recorded acoustic emissions confirm that, locally, dynamic ruptures are occurring (Lengliné et al, ; Schmittbuhl et al, ).…”