Critical slip and time dependence in sea ice friction

• Published in: Cold Regions Science and Technology
• Main Authors: Lishman, B, Sammonds, P
• Format: Text
• Language: unknown
• Published: Elsevier 2013
• Subjects: Thumb; Sea ice
• Online Access: https://openresearch.lsbu.ac.uk/item/878zx; https://openresearch.lsbu.ac.uk/download/0819aa878f84dc1a04851a47568be724a6df24df431846fca18f6d94cf60e223/1967463/2013%20CRST%20Critical%20Slip%20as%20accepted.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.