Interfacial Shear Cracks in Thin Films on Disordered Substrates

Konstantindidis A, Zaiser M, Aifantis E (2009)

Publication Status: Published

Publication Type: Conference contribution, Conference Contribution

Publication year: 2009


Book Volume: 1168

Pages Range: 1137-1137

Conference Proceedings Title: AIP Conference Proceedings Vol. 1168

Event location: Rhetymno GR

DOI: 10.1063/1.3241259


In the present study we consider interfacial failure of thin films that are subjected to shear loads, in cases where the interface between the film and the substrate arc disordered, i.e. interfacial shear strength and fracture energy are random functions of position. It is demonstrated that the internal stresses on the interface can be approximated by a second-order gradient of the shear displacement across the interface, and the model used has the same structure, but containing the strain variable in place of the displacement variable u, with similar models studied by Aifantis and co-workers in the context of shear and slip bands in metal plasticity (see, e.g. [1]). Failure, which results by near-surface cracks running along the interface, is induced by shear tractions applied to the free surface of the film and produce shear stresses in the film and on the interface. Cracks along interfaces below or between thin elastic plates have been investigated mainly in view of crack pinning, crack front roughening and crack propagation [2-3]. Interface crack nucleation, which is important for assessing the strength of interfaces not containing pre-existing cracks, was studied in the past for a bulk material [4]. In this study, however, we consider also interface crack nucleation in a weak interface between a thin elastic film and a rigid substrate. The crack nucleation probability is evaluated as a function of stress, geometry and statistical parameters characterizing the fluctuating shear strength/fracture energy of the interface. The failure stress distribution and the size dependence of the system strength are then evaluated [5]. In addition, the behavior of pre-existing interface cracks which become distorted as they advance across weak regions and get arrested at regions of elevated strength. The interplay between crack front elasticity, which tends to keep the crack front straight, and disorder, which tends to surrogate its front's shape, gives rise to the mutually related phenomena of crack front roughening and crack pinning. The pinning length above which the crack roughens and the associated increase in the critical crack driving force are also determined [6]. The theoretical predictions are validated by numerical simulations.

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Konstantindidis, A., Zaiser, M., & Aifantis, E. (2009). Interfacial Shear Cracks in Thin Films on Disordered Substrates. In AIP Conference Proceedings Vol. 1168 (pp. 1137-1137). Rhetymno, GR.


Konstantindidis, Avraam, Michael Zaiser, and Elias Aifantis. "Interfacial Shear Cracks in Thin Films on Disordered Substrates." Proceedings of the International Conference on Numerical Analysis and Applied Mathematics 2009, Rhetymno 2009. 1137-1137.

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