Friction of Shear-Fracture Zones
Riikilä, T., Pylväinen, J. ., & Åström, J. (2017). Friction of Shear-Fracture Zones. Physical Review Letters, 119 (25), 255501. doi:10.1103/PhysRevLett.119.255501
Published inPhysical Review Letters
© 2017 American Physical Society. Published in this repository with the kind permission of the publisher.
A shear fracture of brittle solids under compression undergoes a substantial evolution from the initial microcracking to a fully formed powder-filled shear zone. Experiments covering the entire process are relatively easy to conduct, but they are very difficult to investigate in detail. Numerically, the large strain limit has remained a challenge. An efficient simulation model and a custom-made experimental device are employed to test to what extent a shear fracture alone is sufficient to drive material to spontaneous selflubrication. A “weak shear zone” is an important concept in geology, and a large number of explanations, specific for tectonic conditions, have been proposed. We demonstrate here that weak shear zones are far more general, and that their emergence only demands that a microscopic, i.e., fragment-scale, stress relaxation mechanism develops during the fracture process.