The Role of the Third Deviatoric Stress Invariant in the Creep of Ice

冰变形实验室和现场观测资料的分析 冰川测量，加上初步双轴蠕变 实验表明，应力配置（应力作用在 方向以外的方向，其中应变率是 测量）可能会影响冰的变形率远远超过 这是格伦流动定律所提出的 这项研究将涉及 制备的冰在简单剪切和在简单剪切同时 在威斯康星州大学的一个低温实验室里进行压缩实验， 河流瀑布。 这些实验将检验格伦的 流动定律，它假设独立于第三个不变量， 描述了冰在双轴应力下的变形。 结果 应允许，如有必要，修改流动定律，以更 基于第二和第三变体的一般形式。 一 这项研究的第二部分将涉及进行联合应力 对冰川冰样品进行的测试显示出广泛的晶体 织物和粒度的流动规律的形式进行调查 对于各向异性冰。

Analysis of ice deformation data from laboratories and from field measurements on glaciers, coupled with preliminary biaxial creep experiments, suggest that stress configuration (stresses acting in directions other that the direction in which the strain rate is measured) may effect the deformation rate of ice much more than that suggested by Glenn's Flow Law. This study will involve prepared ice in simple shear and in simple shear with simultaneous compression in a cold laboratory at the University of Wisconsin- River Falls. These experiments will test the accuracy of Glen's Flow Law, which assumes independence from the third invariant in describing deformation of ice under biaxial stresses. Results should allow, if necessary, modification of the flow law to a more general form based on both the second and third variants. A second part of this study will involve conducting combined stress tests on glacier ice samples exhibiting a broad range of crystal fabrics and grain sizes to investigate the form of the flow law for anisotropic ice.