Deformation of ice under low stresses

Abstract

This study confirms the existence of two flow laws for polycrystalline ice. One describes the behaviour of ice before the inflection point of a constant stress test, and one the behaviour well into the tertiary portion of the strain–time curve. Each flow law may be represented by a power law with an exponent of 3.0.The inflection point in constant stress experiments and the peak in constant strain rate experiments is shown to occur at about 1% strain in experiments conducted in the ductile material behaviour range. A Cottrell–Aytekin relationship has been used to fit the strain–time material behaviour up to the inflection point.The flow law of ice valid below 1% strain is shown to be dependent on the grain size ratio of the ice. The grain size ratio is a measure of the size effect of the sample tested. The temperature influence on the flow law is best described by using the inverse temperature relationship described by Voytkovskiy. Keywords: ice, creep deformation, long-term, failure strain.