Tertiary Flow Relations for Compression and Shear Components in Combined Stress Tests on Ice

The attainment of tertiary flow in ice involves the nonlinear response to the combination of applied stresses and the alteration of both the ice crystals and the polycrystalline aggregate. Tertiary flow rates for individual component strain rates from a series of ice deformation experiments under combined shear and compression stresses are presented, and the departure from the predictions of isotropic flow relations is quantified. A simple generalisation of the flow relations is suggested.