Composition of Sea Ice and Its Tensile Strength
Composition of Sea Ice and Its Tensile Strength

Author: A. Assur

Publisher:

Published: 1960

Total Pages: 68

ISBN-13:

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Part of the salts contained in sea water are trapped in sea ice upon freezing. They form liquid and solid inclusions in a systematic pattern. The amount depends upon temperature and salinity. A detailed table of phase relations is given and a general theory is derived to show how the internal cavities may affect the strength of sea ice. The general theory leads to specific models. The principle of ring tensile strength tests is explained and a series for evaluation is given. Test data lead to a substantiation of theoretical principles and to an illustration of several hypotheses concerning the effect of solid salt inclusions upon strength. Observed sea ice phenomena are explained on the basis of internal structure. (Author).

The Mechanical Properties of Sea Ice
The Mechanical Properties of Sea Ice

Author: W. F. Weeks

Publisher:

Published: 1967

Total Pages: 100

ISBN-13:

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The review discusses the state of thinking of each of the main national groups investigating sea ice and gives an overall appraisal of the field as a whole. Emphasis is placed on (1) the physical basis for interpreting sea ice strength (phase relations, air volume, and structural considerations), (2) theoretical considerations (strength models, air bubbles and salt reinforcement, and interrelations between growth conditions and strength), (3) experimental results (tensile, flexural, shear, and compressive strength, elastic modulus, shear modulus and Poisson's ratio, time dependent effects, and creep), and (4) plate characteristics. The paper includes a review of problems in sea ice investigations, relates the chemical, crystallographic, mechanical, and physical aspects involved, and concludes by showing how to utilize this knowledge to solve practical problems. (Author).

Understanding the Variations of the Physical Properties of Sea Ice
Understanding the Variations of the Physical Properties of Sea Ice

Author: W. F. Weeks

Publisher:

Published: 1967

Total Pages: 28

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Information and test results are presented concerning the mechanism of growth, brine content, strength, structure, and dielectric properties of sea ice. Suggestions are given for improving methods of calculating growth conditions and a schematic drawing is given of the solid-liquid interface for sea ice together with photomicrographs of sea ice at low temperatures. (Author).

Ice Engineering - Tensile Properties of Sea Ice Grown in a Confined System
Ice Engineering - Tensile Properties of Sea Ice Grown in a Confined System

Author: J. E. Dykins

Publisher:

Published: 1970

Total Pages: 63

ISBN-13:

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Tensile strength envelopes were developed for horizontally and vertically oriented specimens of saline ice. The upper boundary limit in each case represents 1- to 2-ppt salinity ice for temperature range -4C to -27C, while the lower boundary represents 7- to 9-ppt salinity ice for the same temperature. The salinity, density, and petrographic structure of the 7- to 9-ppt natural seawater ice, which was grown in the laboratory, are closely identifiable with the characteristics of sea ice formed in a natural environment. This observation was based on comparison of the upper 44 cm of laboratory ice with a similar thickness of natural sea ice. The tensile strength was found to be a nonlinear function of temperature; there were strong implications, however, that a linear relationship with salinity may exist. The strength was found to be dependent on orientation of the stress field with both the grain (crystal) and subgrain (platelet) structure. Limited study indicates that the tensile strength of saline ice is appreciably reduced as stress rates increase above 25 psi/sec. (Author).

Ice-engineering
Ice-engineering

Author: M. G. Katona

Publisher:

Published: 1973

Total Pages: 156

ISBN-13:

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Increasing operational use od ice areas in polar regions has heightened the requirement for improved knowledge and techniques to analyze the behavior of sea ice. Previous studies on elastic behavior are reviewed with emphasis placed on plate analysis. Classical plate theory and the finite element method are compared in analyzing ice plates, with special attention given to sea-ice airfields. Since elastic analysis is not totally representative of actual ice behavior, a general formulation is presented which gives the assumptions and procedures for both viscoelastic and nonlinear domains of sea-ice behavior. A laboratory program is being initiated to determine material properties that are necessary to extend sea-ice analysis into the inelastic range. (Author).

Sea Ice Strength
Sea Ice Strength

Author: Harold R. Peyton

Publisher:

Published: 1966

Total Pages: 272

ISBN-13:

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The report contains the results from a study of the mechanical and structural properties of sea ice; the study commenced in 1958 and was completed in late 1965. Most of the experimental work is based upon stress-strain tests in both direct compression and direct tension. Approximately 3800 of these tests were made. Those parameters anticipated to have significant effect upon strength were measured: temperature, salinity, rate of loading, crystal size, crystallographic orientation, history of the ice and depth in the ice sheet. All of these are found to be significant except that the history factor itself tended to be determined by the other parameters. The analysis was accomplished primarily by testing models by linear multiple regression. The models selected yield good results with multiple correlation coefficients between 0.70 and 0.98 over a range of petrofabric types. Additional work accomplished in conjunction with construction of offshore oil drilling platforms had provided significant information concerning oscillatory failure of sea ice in compression and strength reduction at very high load rates. The ice failure force oscillation is an ice property and is not primarily a function of the response of the structure. The magnitude of oscillation is large and at a frequency in the range of most space frame structures. The failing ice may cause forced resonant vibration in structures, and the forces are large enough to resonantly vibrate structure weighing several thousand tons. (Author).

RING TENSILE STRENGTH OF SEA ICE.
RING TENSILE STRENGTH OF SEA ICE.

Author: Peter Graystone

Publisher:

Published: 1963

Total Pages: 10

ISBN-13:

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A floating ice sheet, when loaded beyond its bearing capacity, should break under tension. The last decade or so has there-fore seen considerable effort devoted to so-called largescale tests of ultimate tensile strength. An in situ cantilever beam test, for instance, involves the making of two parallel cuts at the sides of the beam and another cut at its free end. The beam is then loaded at its free end at a rapid rate until failure occurs. When the ice sheet is more than a few inches thick, and many of these tests have been carried out on ice up to 6 feet thick, an effort of considerable magnitude is required. Hence, one finds these tests being performed solely by government agencies that have the necessary manpower and facilities. Results are further-more not as reproducible as one would like, being influenced by flaws or weak points that are invariably present in large samples. Even under the best of circumstances, since a sheet of sea ice will, in general, have its salinity and temperature, and hence its brine content, varying with depth, the data can be related only to the gross features of the ice. Small-scale tests, on the other hand, can be performed with relative ease and rapidity, particularly if a procedure that is becoming standard is adopted. This is a test of ultimate ring tensile strength, and the procedure is described in detail by Butkovich. (Author).