CREEP OF ICE AT LOW STRESSES.

• Main Authors: Butkovich,T. R., Landauer,J. K.
• Other Authors: SNOW ICE AND PERMAFROST RESEARCH ESTABLISHMENT WILMETTE ILL
• Format: Text
• Language: English
• Published: 1960
• Subjects: Snow; Ice and Permafrost; (*ICE; CREEP); STRESSES; GLACIERS; SHEAR STRESSES; MEASUREMENT; STRAIN(MECHANICS); Ice; permafrost
• Online Access: http://www.dtic.mil/docs/citations/AD0653135; http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=AD0653135

Low stress creep measurements were made on commercial ice and small-grained glacier ice in the temperature range from -1.3 to -18.9C at stresses down to about 10,000 dynes/sq. cm. The uniaxial stresses and strain rates were reduced to shear stresses and shear strain rates by respectively dividing and multiplying the former by the square root of 3. The log shear strain rate vs log shear stress curves was essentially linear for the low-stress creep measurements. Assuming a linear flow law for low-stress creep, activation energies for creep of about 14,300 cal/mole were determined. It can also be seen that the smaller-grained ice has a higher viscosity coefficient. The observed activation energy for creep of ice is probably that for self-diffusion. Although lacking a concrete deformation mechanism, the rate process theory, which leads to a hyperbolic sine stress dependence, seems to best describe the experimental results. (Author)