Instabilities in stress corrosion and the transition to brittle failure

Koehn, D. , Arnold, J., Jamtveit, B. and Malthe-Sørenssen, A. (2003) Instabilities in stress corrosion and the transition to brittle failure. American Journal of Science, 303(10), pp. 956-971. (doi: 10.2475/ajs.303.10.956)

Abstract

Studies on the dissolution of stressed crystals have shown that stress corrosion can lead to roughening of interfaces. The corrosion pattern develops due to gradients in elastic energy along a free crystal surface with an initial roughness. Dissolution will cause further increase in elastic energy, which in turn will speed up dissolution, the so-called Asaro-Tiller-Grinfeld instability. We present a numerical model in order to study the effect of stress corrosion that is observed in physical experiments of interface roughening of brittle salt crystals. In the simulations a salt crystal that is immersed in saturated brine is stressed and dissolution patterns develop. Stress corrosion can lead to an Asaro-Tiller-Grinfeld instability that develops into cusp instabilities and crack-like structures or anti-cracks. The system breaks its symmetry and produces a secondary instability where the number of growing anti-cracks is reduced. This coarsening of the surface roughness is due to stress-shielding effects of growing anti-cracks. Finally, one single anti-crack remains on each side of an initial hole as a "superstructure". The large anti-crack grows at an almost constant speed and eventually leads to brittle failure of the crystal. This mechanism may be important not only for dissolution-precipitation creep but also other phase-transitions and may lead to large scale brittle failure that can be associated with earthquakes.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Koehn, Dr Daniel
• Authors: Koehn, D., Arnold, J., Jamtveit, B., and Malthe-Sørenssen, A.
• Subjects: Q Science > QE Geology
• College/School: College of Science and Engineering > School of Geographical and Earth Sciences
• Journal Name: American Journal of Science
• ISSN: 0002-9599