Propagating compaction bands in confined compression of snow

• Published in: Nature physics Vol. 13; no. 3; pp. 272 - 275
• Main Authors: Barraclough, Thomas W., Blackford, Jane R., Liebenstein, Stefan, Sandfeld, Stefan, Stratford, Tim J., Weinländer, Gerhard, Zaiser, Michael
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.03.2017; Nature Publishing Group
• Subjects: 639/301/1034/1036; 639/301/923; 639/766/530/2803; Atomic; Behavior; Classical and Continuum Physics; Complex Systems; Compressing; Condensed Matter Physics; Critical phenomena; Deformation; Formations; letter; Localization; Material properties; Mathematical and Computational Physics; Molecular; Optical and Plasma Physics; Oscillations; Physical properties; Physics; Propagation; Snow; Softening; Strain localization; Strain rate; Theoretical
• ISSN: 1745-2473; 1745-2481
• DOI: 10.1038/nphys3966

When deforming snow slowly, it resists. But when applying a deformation rapidly, it gives in more easily. Experiments now reveal propagating deformation bands and the localization of strain in compressed snow — both natural and artificial. Some materials are strong in response to a slowly applied deformation, yet weak when subject to rapid deformations—a materials property known as strain-rate softening 1 . Snow exhibits such behaviour: it is comparatively strong at low deformation rates, where it is quasi-plastic, but weak at high rates, where it deforms in a quasi-brittle manner 2 . During deformation, strain-rate-softening materials ranging from metals 3 , 4 to micellar systems 5 exhibit complex spatio-temporal deformation patterns, including regular or chaotic deformation-rate oscillations and travelling deformation waves 6 . Here we report a systematic investigation of such phenomena in snow and show that snow can deform with the formation and propagation of localized deformation bands accompanied by oscillations of the driving force. We propose a model that accounts for these observations. Our findings demonstrate that in snow, strain localization can occur even in initially homogeneous samples deforming under homogeneous loads.