A dislocation-based analysis of strain history effects in ice

Abstract

Abstract The cyclic loading response of ice specimens can be analysed with a dislocation-based model of anelasticity to produce an estimate of the effective mobile dislocation density. Moreover, the cyclic loading response is sufficiently sensitive to track the dislocation density changes that occur during creep straining. A combination of cyclic and creep loading experiments can thus be employed to gain crucial insight regarding the relationship between the dislocation density that evolves during creep straining and the anelastic and viscous components of strain. Creep and cyclic loading experiments have been conducted on laboratory-prepared saline and freshwater ice specimens to shed light on the effects of temperature, creep stress and accumulated strain on the mobile dislocation density and thereby to support the further development of a physically based constitutive model for ice. The findings indicate that, in addition to the expected stress and strain dependence, the dislocation density that develo...