ON THE STRAIN-RATE SENSITIVITY OF COLUMNAR ICE

A power law relation between stress and strain rate of the form sigma proportional to (epsilon) over dot(1/n) was used to describe the respo nse to strain rate of S1 ice loaded across the columns at -10 degrees C. The rate exponent. n, decreased with increasing strain from about 4 .6 at an observed peak on the load displacement curve to approximately 2.6 at a shortening of 2%. Analysis of these results and of the resul ts of other authors on different forms of ice deformed at the same tem perature suggests that the power law exponent, n, is proportional to F -c/F-g. The parameter F-c/F-g is the far-field basal dislocation climb force divided by the glide force.