Critical slip and time dependence in sea ice friction

• Published in: Cold Regions Science and Technology
• Main Authors: Lishman, Ben, Sammonds, Peter R., Feltham, Daneil L.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Elsevier 2013
• Subjects: Thumb; Sea ice
• Online Access: https://centaur.reading.ac.uk/34578/; https://centaur.reading.ac.uk/34578/1/1-s2.0-S0165232X13000487-main.pdf; https://doi.org/10.1016/j.coldregions.2013.03.004

Recent research into sea ice friction has focussed on ways to provide a model which maintains much of the clarity and simplicity of Amonton's law, yet also accounts for memory effects. One promising avenue of research has been to adapt the rate- and state- dependent models which are prevalent in rock friction. In such models it is assumed that there is some fixed critical slip displacement, which is effectively a measure of the displacement over which memory effects might be considered important. Here we show experimentally that a fixed critical slip displacement is not a valid assumption in ice friction, whereas a constant critical slip time appears to hold across a range of parameters and scales. As a simple rule of thumb, memory effects persist to a significant level for 10 s. We then discuss the implications of this finding for modelling sea ice friction and for our understanding of friction in general.