scholarly journals Uniaxial compressive strength of first-year and multi-year sea ice

1984 ◽  
Vol 11 (1) ◽  
pp. 82-91 ◽  
Author(s):  
N. K. Sinha
Keyword(s):  
Compressive Strength ◽  
Sea Ice ◽  
Strain Rate ◽  
Fresh Water ◽  
Horizontal Plane ◽  
Rate Sensitivity ◽  
Ductile Material ◽  
First Year ◽  
Water Ice ◽  
Frazil Ice

Strain-rate and stress-rate sensitivity of the compressive strength of first-year columnar-grained ice, first-year congealed frazil ice, and columnar-grained ice from an old floe have been investigated with load applied in the horizontal plane. In spite of similar salinity and density, the frazil ice proved to be considerably stronger than the columnar-grained ice. The strength of porous old floe ice with columnar-grained structure was very much the same as that of first-year ice of similar structure, but the clear bulk ice of the old floe was strongest. Rate sensitivity of strength for the three types of saline ice was similar to that of fresh-water ice. Ductility of the old clear ice (as measured by the strain at upper yield) was the same as that of fresh-water ice; ductility of porous old ice was comparable to that of new frazil ice. New columnar-grained ice proved to be the most ductile material. Key words: columnar-grained, compressive strength, ductility, first-year, frazil, multi-year, rate sensitivity, sea ice.

scholarly journals Study on the Properties of Compressive Strength of Sea Ice and Fresh Water Ice

1992 ◽  
Vol 8 ◽  
pp. 123-127
Author(s):  
Takahiro Takeuchi ◽  
Hirofumi Tabuchi ◽  
Akira Imaizumi ◽  
Kunio Enoki ◽  
Satoshi Okamoto ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Sea Ice ◽  
Fresh Water ◽  
Water Ice

scholarly journals Field Test 1 of Compressive Strength of First-Year Sea Ice

1983 ◽  
Vol 4 ◽  
pp. 253-259 ◽  
Author(s):  
N. K. Sinha
Keyword(s):  
Compressive Strength ◽  
Sea Ice ◽  
Failure Time ◽  
Rate Sensitivity ◽  
Test System ◽  
First Year ◽  
Test Machine ◽  
Baffin Island ◽  
Test Results ◽  
Average Strain Rate

A test program undertaken in April 1981 on the uniaxial compressive strength of freshly recovered first-year columnar-grained sea ice at a portable field laboratory floating on top of the ice cover in Eclipse Sound, Baffin Island, Canadian Arctic, is reported. Using a small battery-operated test machine, both vertical and horizontal samples were tested so that the load could be applied either parallel or perpendicular to the axis of the columns. Rate sensitivity of the observed strength is discussed in terms of measured average strain-rate and average stress-rate to upper yield or failure. Strain and time aspects of the test results are considered as well. Although vertical samples showed considerably greater strength than horizontal samples, no significant differences were detected in the failure strains. Examination of the interdependence of failure stress and failure time revealed certain anomalies in the results for vertical samples that could be linked to the performance characteristics of the test machine. As such problems could be common to any test system, methods of analysis are proposed for rational examination of the results.

Uniaxial Constant Compressive Stress Creep Tests on Sea Ice

1995 ◽  
Vol 117 (4) ◽  
pp. 283-289 ◽  
Author(s):  
N. K. Sinha ◽  
C. Zhan ◽  
E. Evgin
Keyword(s):  
Compressive Strength ◽  
Sea Ice ◽  
Strain Rate ◽  
Compressive Stress ◽  
Axial Strain ◽  
Acoustic Emissions ◽  
Constant Strain Rate ◽  
Rate Sensitivity ◽  
Load Test ◽  
Creep Tests

First-year columnar-grained sea ice from Resolute Passage (74° 42′ N, 94° 50′ W), off Barrow Strait in the Canadian High Arctic, was tested under constant uniaxial compressive stress applied normal to the length of the columns. Creep tests were performed at 263 K, 253 K, and 243 K in the stress range of 0.7 to 2.5 MPa, using prismatic samples with dimensions of 50 mm × 100 mm × 250 mm. Because three-dimensional creep data are extremely useful for developing constitutive equations, axial strain was measured in conjunction with the measurements of two lateral strains and acoustic emissions. The deformations were measured using displacement gages mounted on the samples. A description of the experimental procedures and the observations are presented here. One-to-one correspondence has been obtained between the present results on the dependence of minimum creep rate on stress and previous data on the dependence of uniaxial compressive strength on strain rate under constant strain rate. The strain-rate sensitivity of compressive strength can, therefore, be obtained from creep tests which can be performed by using simple dead-load test systems.

scholarly journals Field Test 1 of Compressive Strength of First-Year Sea Ice

1983 ◽  
Vol 4 ◽  
pp. 253-259 ◽  
Author(s):  
N. K. Sinha
Keyword(s):  
Compressive Strength ◽  
Sea Ice ◽  
Failure Time ◽  
Rate Sensitivity ◽  
Test System ◽  
First Year ◽  
Test Machine ◽  
Baffin Island ◽  
Test Results ◽  
Average Strain Rate

A test program undertaken in April 1981 on the uniaxial compressive strength of freshly recovered first-year columnar-grained sea ice at a portable field laboratory floating on top of the ice cover in Eclipse Sound, Baffin Island, Canadian Arctic, is reported. Using a small battery-operated test machine, both vertical and horizontal samples were tested so that the load could be applied either parallel or perpendicular to the axis of the columns. Rate sensitivity of the observed strength is discussed in terms of measured average strain-rate and average stress-rate to upper yield or failure. Strain and time aspects of the test results are considered as well. Although vertical samples showed considerably greater strength than horizontal samples, no significant differences were detected in the failure strains. Examination of the interdependence of failure stress and failure time revealed certain anomalies in the results for vertical samples that could be linked to the performance characteristics of the test machine. As such problems could be common to any test system, methods of analysis are proposed for rational examination of the results.

scholarly journals Tensile Strength of NaCl Ice

1962 ◽  
Vol 4 (31) ◽  
pp. 25-52 ◽  
Author(s):  
W. F. Weeks
Keyword(s):  
Tensile Strength ◽  
Sea Ice ◽  
Fresh Water ◽  
Eutectic Point ◽  
Water Ice ◽  
Average Value ◽  
Freshwater Ice ◽  
The One ◽  
Image Position ◽  
Bodies Of Water

AbstractTo resolve some of the factors causing strength variation in natural sea ice, fresh water and five different NaCl–H2O solutions were frozen in a tank designed to simulate the one-dimensional cooling of natural bodies of water. The resulting ice was structurally similar to lake and sea ice. The salinity of the salt ice varied from 1‰ to 22‰. Tables of brine volumes and densities were computed for these salinities in the temperature range 0° to −35° C. The ring-tensile strength σ of fresh-water ice was found to be essentially temperature independent from −10° to −30°C., with an average value of 29.6±8.5 kg./cm.2at −10° C. The strength of salt ice at temperatures above the eutectic point (–21.2° C.) significantly decreases with brine volumev;. The σ–axis intercept of this line is comparable to the a values determined for fresh ice indicating that there is little, if any, difference in stress concentration between sea and lake ice as a result of the presence of brine pockets. The strength of ice containing NaCl.2H2O is slightly less than the strength of freshwater ice and is independent of the volume of solid salt and the ice temperature. No evidence was found for the existence of either phase or geometric hysteresis in NaCl ice. The strength of ice at sub-eutectic temperatures, however, is decreased appreciably if the ice has been subjected to temperatures above the eutectic point; this is the result of the redistribution of brine during the warm-temperature period. Short-term cooling produces an appreciable (20 per cent) decrease in strength, in fresh-water and NaCl.2H2O ice. The present results are compared with tests on natural sea ice and it is suggested that the strength of freshwater ice is a limit which is approached but not exceeded by cold sea ice and that the reinforcement of brine pockets by Na2SO4.10H2O is either lacking or much less than previously assumed.

scholarly journals II. Ice observations

1859 ◽  
Vol 9 ◽  
pp. 609-611 ◽  
Keyword(s):  
Specific Gravity ◽  
Sea Ice ◽  
Fresh Water ◽  
Sea Water ◽  
Water Ice ◽  
Rate Of Growth ◽  
Abundant Evidence ◽  
Domestic Use ◽  
The Subject ◽  
Original Water

The contradictory statements of Dr. Sutherland and Dr. Kane, with regard to the saltness of the ice formed from sea-water,—the former maintaining that sea-water ice contains about one-fourth of the salt of the original water; the latter, that if the cold be sufficiently intense, there will be formed from sea-water a fresh and purer element fit for domestic use,—induced the author to take advantage of his position, as naturalist to the expedition now in the northern seas, to reinvestigate the subject. The changes which he has observed sea-water to undergo in freezing are the following. When the temperature falls below + 28°⋅5, it becomes covered with a thin pellicle of ice; after some time this pellicle becomes thicker and presents a vertically striated structure, similar to that of the ordinary cakes of sal-ammoniac. As the ice further increases in thickness, it becomes more compact, but the lowest portion still retains the striated structure. On the surface of the ice, saline crystals, designated by the author “efflorescence,” soon begin to form, at first few in number and widely separated, but gradually forming into tufts and ultimately covering the whole surface. At first, the increase in thickness of the ice is rapid, but afterwards the rate of growth is much slower and more uniform. The ice formed yields, on being melted, a solution differing in specific gravity according to the temperature at the time of congelation, its density being less, the lower the temperature at which the process of congelation took place. Although the author’s observations extended from + 28°⋅5 to —42°, he was never able to obtain fresh-water from sea-ice, the purest specimen being of specific gravity 1⋅005, and affording abundant evidence of the presence of salts, especially of chloride of sodium, in such quantity as to render it unfit for domestic purposes.

scholarly journals Ice Lithologies and Structure of Ice Island Arlis II

1964 ◽  
Vol 5 (37) ◽  
pp. 17-38 ◽  
Author(s):  
David D. Smith
Keyword(s):  
Sea Ice ◽  
Arctic Ocean ◽  
Fresh Water ◽  
Structural Features ◽  
The Arctic ◽  
Glacial Ice ◽  
Water Ice ◽  
Central Block ◽  
The Arctic Ocean

AbstractIce island ARLIS II, which is adrift in the Arctic Ocean, is a 1.3 km. wide and 3.8 km. long fragment of shelf ice 12–25 m. thick, which preserves several structural features heretofore undescribed in ice. The island is composed of an irregular central block of foliated, locally debris-rich, grey glacial ice bordered in part by extensive areas of stratified bluish sea ice. The central block contains a series of narrow, elongate, sub-parallel dike-like septa of massive fresh-water ice and a large tongue-like body of tightly folded, coarse banded ice. Both the septa and the tongue cut across the foliation and debris zones of the grey ice.The margins of the central block are penetrated by a series of elongate, crudely wedge-shaped re-entrants occupied by salients of bluish sea ice. Two broad, arch-like plunging anticlines deform the stratified sea ice along one margin of the block.The foliation and debris zones in the glacial ice are relict features inherited from the source glacier. The septa formed as crevasse and basal fracture fills. Salients represent fills formed in the irregular re-entrants along the margins of the glacial ice mass. The tongue of tightly folded, banded ice represents an earlier generation salient deformed by compressive forces as the fill built up. The broad anticlines are apparently the result of warping in response to differential ablation but the small, tight plunging folds on their noses and limbs are probably the result of compressive forces.

scholarly journals The mechanical properties of saline ice under uniaxial compression

1994 ◽  
Vol 19 ◽  
pp. 39-48 ◽  
Author(s):  
Gary A. Kuehn ◽  
Erland M. Schulson
Keyword(s):  
Mechanical Properties ◽  
Sea Ice ◽  
Strain Rate ◽  
Uniaxial Compression ◽  
Growth Direction ◽  
First Year ◽  
Polar Regions ◽  
Deformation And Fracture ◽  
Specimen Orientation ◽  
Ductile To Brittle Transition

Understanding the mechanical properties of saline ice is important for engineering design as well as for operations in polar regions. In order to gain understanding of the basic mechanisms of deformation and fracture, laboratory-grown columnar saline ice, representative of first-year sea ice, was tested in uniaxial compression under a variety of conditions of Strain rate (10−7to 10−1s−1), temper-aiure (−40°, −20°, −10° and −5°C) and orientation (loading vertically or horizontally: i.e. parallel or perpendicular to the growth direction). The range of strain rate spanned the ductile-to-brittle transition for every combination of temperature and specimen orientation. The results of over 250 tests are reported. Mechanical properties, failure mode and ice structure are analyzed with respect to the testing conditons. The results show that strength is dependent upon the ice structure, orientation, strain rate and temperature. During loading in the ductile regime the structure is altered (e.g. by recrystallization), whereas in the brittle regime the majority of the structural change is through cracking. The results are compared to results from the literature on both natural sea ice and laboratory-grown saline ice. Where possible, they are interpreted in terms of micromechanica] models.

Brittle compressive failure of ice: proportional straining vs proportional loading

2006 ◽  
Vol 52 (177) ◽  
pp. 248-250 ◽  
Author(s):  
E.M. Schulson ◽  
D. Iliescu
Keyword(s):  
Sea Ice ◽  
Strain Rate ◽  
First Year ◽  
Compressive Failure ◽  
Proportional Loading ◽  
Freshwater Ice

AbstractProportional straining experiments have been performed on columnar-grained S2 freshwater ice biaxially compressed across the columns at –10°C at a strain rate of (4.5 ± 1.5) × 10–3 s–1. The results are compared with those obtained earlier (Iliescu and Schulson, 2004) from the same kind of material deformed to terminal failure under the same conditions, but through proportional loading. The exercise shows that the biaxial strength is practically independent of the path taken, at least under low confinement where Coulombic shear faulting limits terminal failure. First-year sea ice is expected to exhibit the same behavior.

Spherical shells in inelastic collision with a rigid wall—tentative analysis and recent quasi-static testing

1994 ◽  
Vol 29 (1) ◽  
pp. 17-41 ◽  
Author(s):  
A N Kinkead ◽  
A Jennings ◽  
J Newell ◽  
J C Leinster
Keyword(s):  
Spherical Shell ◽  
Strain Rate ◽  
Rate Sensitivity ◽  
Rigid Wall ◽  
Ductile Material ◽  
Spherical Shells ◽  
Static Tests ◽  
Static Testing ◽  
Engineering Department ◽  
Two Phases

This paper considers the crushing which occurs in a spherical shell made of ductile material on striking a rigid wall. A static analysis is developed which allows for strain hardening, while for relatively low impact velocities, such as to permit the effect of inertia to be neglected, strain rate sensitivity is allowed for in an empirical manner. The analysis presented is applicable to spherical shells with a mean radius to thickness ratio exceeding seven, constructed in ductile material obeying a simple power law work hardening relationship. The deformation is assumed to occur in two phases. In the first phase a local flattening of the shell in contact with the rigid wall occurs, while in the second, an axisymmetric dimpling of the previously flattened portion takes place. Other workers have discovered that at radius to thickness ratios exceeding one hundred, a third mode of behaviour takes place when a number of non-axisymmetric nodes can be formed. The analysis in this paper, however, is only applicable to lower ratios when the crushing deformation, although reaching a value of half the radius, remains axisymmetric, as is borne out in all the experimental results examined for correlation. A number of assumptions and simplifications are made, all of which are clearly stated below. Reference is made to earlier papers on this subject and a comparison is made of correlations by such earlier work and by the present analysis in respect of a group of quasi-static tests carried out by the Civil Engineering Department of the Queen's University of Belfast under a Leverhulme Trust fellowship funding: this is described in detail in Appendix 1. The result of a moderate velocity impact test on a spherical shell of 625 mm diameter is utilized to examine the correlation given by the present analysis taking strain rate effect into account. Note: the first author was mainly concerned with the analysis, while the co-authors carried out the experimental work detailed in Appendix 1.

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