The influence of damage on the creep behaviour of ice subject to multiaxial compressive stress states

Kenny, Shawn Patrick (1992) The influence of damage on the creep behaviour of ice subject to multiaxial compressive stress states. Masters thesis, Memorial University of Newfoundland.

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Abstract

Medium-scale indentation tests, such as Pond Inlet (1984) and Hobson’s Choice Ice Island (1989, 1990), have shown that during rapid crushing events the failure zone can be characterized by distinct sub-regions. The behavior of the damaged ice and crushed material located at hard spots or ‘critical zones’ of moderate to high confining pressures during interaction events is seen as the key to dynamic fluctuations in load and local peak pressures. – Consequently, an experimental program investigating the influence of microcracks on the creep response of polycrystalline, granular freshwater ice subject to hydrostatic confinement was conducted. The main objective of the test program was to better understand the creep behavior of damaged ice generated at the contact zone during ice-structure interactions. A series of compressive stress pulses, which ranged from 0.3 MPa to 2.6 MPa, were applied to intact and pre-damaged samples under confining pressures of 0, 4, 10 and 20 MPa. The damage state was nominally uniform for all tests which was developed by loading the ice sample at a constant displacement rate of 10⁻⁴ s⁻¹ to 2% axial strain. – Although the elastic response was marginally influenced by the pre-damaging path, the magnitude and rate of creep strain was significantly enhanced independently of the hydrostatic pressure. Also, the creep deformation was non-linear with applied deviatoric stress and exhibited a tendency for viscous processes to dominate at higher load levels. One of the key findings was the magnitude of lateral strain, hence volumetric deformation, and shear strain developed independently of the confining pressures investigated. The considerable enhancement and non-linearity of creep strain evident in the experimental program has significant implications when considering full-scale events. Furthermore, the findings point to possible simplifications to ice-load models and constitutive relationships that may be utilized in continuum analysis of ice-structure interaction.

Item Type: Thesis (Masters)
URI: http://research.library.mun.ca/id/eprint/10791
Item ID: 10791
Additional Information: Bibliography: leaves 109-114.
Department(s): Engineering and Applied Science, Faculty of
Date: 1992
Date Type: Submission
Library of Congress Subject Heading: Ice mechanics; Ice--Creep; Stress concentration.

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