Accession Number : AD0755336

Title :   Continuous Observations of the Structural Changes in Deforming Polycrystalline Ice.

Descriptive Note : Scientific rept.,

Corporate Author : WASHINGTON UNIV SEATTLE DEPT OF ATMOSPHERIC SCIENCES

Personal Author(s) : Sprenger,Robert M.

Report Date : NOV 1972

Pagination or Media Count : 76

Abstract : An apparatus was constructed to continuously observe structural changes accompanying the deformation of polycrystalline ice. Thin sections of natural glacier ice and arctic sea ice were subjected to compressive stresses of several bars at temperatures near the melting point. Polarized light was used to obtain photographic sequences of the deformation. The observations were designed so as not to interrupt the deformation, in contrast to previous studies. Grain boundary migration and basal glide were observed over a wide range of stresses and temperatures, while polygonization and various types of recrystallization were found to be restricted to smaller stress-temperature regions. No voids or cracks were observed to form in the ice during these experiments. Regelation and intercrystalline sliding were not detected. Photographs and tracings of the deformation sequences are presented, together with other quantitative data related to the observations. (Author)

Descriptors :   (*GLACIERS, DEFORMATION), (*SEA ICE, DEFORMATION), STRESSES, STRAIN(MECHANICS), CREEP, MELTING, TEST EQUIPMENT, CRYSTAL STRUCTURE, THESES

Subject Categories : Soil Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE