Scale effects on the in-situ tensile strength and fracture of ice. Part II: First-year sea ice at Resolute, N.W.T

Dempsey, J. P.; Adamson, Robert; Mulmule, S. V.

doi:10.1007/978-94-011-4659-3_19

Cited by 59 publications

(63 citation statements)

References 36 publications

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“…Weiss [2003] analyzed the crevasse pattern of a temperate alpine glacier and found an exponential distribution of crevasse size, with a minimum crevasse size of 10 m. The spacing between crevasses could be well approximated by a lognormal distribution with a mode of 12.6 m. These results suggest that the size of the FPZ is in the order of magnitude of 10 m. This result is confirmed by the numerical simulations presented in section 5. For viscoelastic deformations, according to the large-scale experiments of Dempsey et al [1999] and the size effect theory of Bažant [1999], the size of the FPZ amounts approximately to 3 m. Dempsey et al [1999] observed also a constant value of the fracture toughness above a characteristic sample size of 3 m. This behavior can be understood as a geometrical behavior rather than a change of the fracture characteristics with size. At a given load, the size of the fracture process zone of a notched sample is independent of the sample size.…”

Section: Appendix A: Critical Damage and Inhomogeneitiesmentioning

confidence: 86%

Dynamic damage model of crevasse opening and application to glacier calving

2005

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[1] Theory and applications of continuum damage mechanics for ice are discussed, and on this basis, an ice damage model, valid at low stresses, is proposed. The model describes the damage itself, the rheology of the damaged ice, and the damage evolution. A local damaging and healing law is considered, and its parameterization is motivated. The model parameters are inferred from published data of laboratory experiments. The model is subsequently implemented in a finite element code and applied to the prediction of a calving process and to the destabilization of an ice chunk from a hanging glacier. Numerical results show good agreement with field measurements.Citation: Pralong, A., and M. Funk (2005), Dynamic damage model of crevasse opening and application to glacier calving,

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Section: Appendix A: Critical Damage and Inhomogeneitiesmentioning

confidence: 86%

Dynamic damage model of crevasse opening and application to glacier calving

2005

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“…Laboratory experiments by Richter-Menge and Jones [1993] showed that sea ice tensile strength significantly depends on temperature and porosity and can vary from 0.2 MPa at −3°C up to 0.78 MPa at −20°C. Dempsey et al [1999] considered a crack propagation experiment on a block of ice 0.5-80 m wide and concluded that the tensile strength depends on this floe scale as 0.59/(1 + L/0.26)…”

Section: Model Configurationmentioning

confidence: 99%

Effect of shear rupture on aggregate scale formation in sea ice

2010

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[1] A discrete element model is used to study shear rupture of sea ice under convergent wind stresses. The model includes compressive, tensile, and shear rupture of viscous elastic joints connecting floes that move under the action of the wind stresses. The adopted shear rupture is governed by Coulomb's criterion. The ice pack is a 400 km long square domain consisting of 4 km size floes. In the standard case with tensile strength 10 times smaller than the compressive strength, under uniaxial compression the failure regime is mainly shear rupture with the most probable scenario corresponding to that with the minimum failure work. The orientation of cracks delineating formed aggregates is bimodal with the peaks around the angles given by the wing crack theory determining diamond-shaped blocks. The ice block (floe aggregate) size decreases as the wind stress gradient increases since the elastic strain energy grows faster leading to a higher speed of crack propagation. As the tensile strength grows, shear rupture becomes harder to attain and compressive failure becomes equally important leading to elongation of blocks perpendicular to the compression direction and the blocks grow larger. In the standard case, as the wind stress confinement ratio increases the failure mode changes at a confinement ratio within 0.2-0.4, which corresponds to the analytical critical confinement ratio of 0.32. Below this value, the cracks are bimodal delineating diamond shape aggregates, while above this value failure becomes isotropic and is determined by small-scale stress anomalies due to irregularities in floe shape.

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“…There is a large body of existing work that describes the compressive and tensile behavior of ice (Haynes, 1978;Currier and Schulson, 1982;Dempsey et al, 1999a;Dempsey et al, 1999b;Schulson, 1999;Schulson et al, 2005), and its fracture properties (Nixon and Schulson, 1987;Weber and Nixon, 1996;Dempsey et al, 1999a;Dempsey et al, 1999b;Uchida and Kusumoto, 1999), in either single-crystal or polycrystalline forms. Most of these studies have focused on the mechanical behavior in the creep and quasi-static deformation regimes.…”

Section: Introductionmentioning

confidence: 98%

High strain-rate behavior of ice under uniaxial compression

Shazly

Prakash

Lerch³

2009

International Journal of Solids and Structures

104

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a b s t r a c tIn the present study, a modified split Hopkinson pressure bar (SHPB) is employed to investigate the dynamic response of ice under uniaxial compression in the range of strain rates from 60 to 1400 s À1 and at initial test temperatures of À10 and À30°C. The compressive strength of ice shows positive strain-rate sensitivity over the range of strain rates employed; a slight influence of ice microstructure is observed, but it is much less than that reported previously for ice deformation under quasi-static loading conditions [Schulson, E.M., IIiescu, D., Frott, A., 2005. Characterization of ice for return-to-flight of the space shuttle. Part 1 -Hard ice. NASA CR-2005-213643-Part 1]. Specimen thickness, within the range studied, was found to have little or no effect on the peak (failure) strength of ice, while lowering the test temperature from À10 to À30°C had a considerable effect, with ice behaving stronger at the lower test temperature. Moreover, unlike in the case of uniaxial quasi-static compression of ice, the effect of specimen end-constraint during the high rate compression was found to be negligible. One important result of these experiments, which may have important implications in modeling ice impacts, involves the post ''peak-stress" behavior of the ice in that the ice samples do not catastrophically lose their load carrying capacity even after the attainment of peak stress during dynamic compression. This residual (tail) strength of the damaged/fragmented ice is sizable, and in some cases is larger than the quasi-static compression strength reported for ice. Moreover, this residual strength is observed to be dependent on sample thickness and the strain rate, being higher for thinner samples and at higher strain-rates during dynamic compression.

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Scale effects on the in-situ tensile strength and fracture of ice. Part II: First-year sea ice at Resolute, N.W.T

Cited by 59 publications

References 36 publications

Dynamic damage model of crevasse opening and application to glacier calving

Dynamic damage model of crevasse opening and application to glacier calving

Effect of shear rupture on aggregate scale formation in sea ice

High strain-rate behavior of ice under uniaxial compression

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