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  • 1
    Series available for loan
    Series available for loan
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
    Associated volumes
    Call number: ZSP-201-82/30
    In: CRREL Report, 82-30
    Description / Table of Contents: Equations are developed that can be used to determine the amount of gas present in sea ice from measurements of the bulk ice density, salinity and temperature in the temperature range o f-2 to -30°C. Conversely these relationships can be used to give the density of sea ice as a function of its temperature and salinity, considering both the presence of gas and of solid salts in the ice. Equations are also given that allow the calculation of the gas and brine volumes in the ice at temperatures other than that at which the bulk density was determined.
    Type of Medium: Series available for loan
    Pages: 13 Seiten , Illustrationen
    Series Statement: CRREL Report 82-30
    Language: English
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  • 2
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    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
    Associated volumes
    Call number: ZSP-201-82/31
    In: CRREL Report, 82-31
    Description / Table of Contents: Information on sea ice conditions in the Bering Strait and the icefoot formation around Fairway Rock, located in the strait, is presented. Cross-sectional profiles of Fairway Rock and the relief of the icefoot are given along with theoretical analyses of the possible forces active during icefoot formation. It is shown that the ice cover most likely fails in flexure as opposed to crushing or buckling, as the former requires less force. Field observations reveal that the Fairway Rock icefoot is massive, with ridges up to 15 m high, a seaward face only 20 degrees from vertical, and interior ridge slopes averaging 33 degrees. The icefoot is believed to be grounded and its width ranges from less than 10 to over 100 m.
    Type of Medium: Series available for loan
    Pages: 44 Seiten , Illustrationen
    Series Statement: CRREL Report 82-31
    Language: English
    Note: CONTENTS Abstract Preface Introduction Bering Strait Field reconnaissance Estimation of ice forces on Fairway Rock 1. Creep deformation 2. Crushing failure 3. Flexural failure 4. Forces required to form floating or grounded pressure ridges along therock or to pile ice on the beaches 5. Buckling failure Driving forces Angle of internal friction of sea ice Summary Literature cited Appendix A: April 1982 field observations at Fairway Rock
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  • 3
    Call number: ZSP-201-85/16
    In: CRREL Report, 85-16
    Description / Table of Contents: This report presents the results of the second phase of a test program designed to obtain a comprehensive understanding of the mechanical properties of multi-year sea ice from the Alaskan Beaufort Sea. In Phase 2, 62 constant-strain-rate uniaxial compression tests were performed on horizontal and vertical ice samples from multi-year pressure ridges to examine the effect of sample orientation on ice strength. Also conducted were 36 constant-strain-rate tension tests, 55 conventional triaxial tests and 35 constant-load compression tests on multi-year pressure ridge samples to provide data for developing ice yield criteria and constitutive laws. Data are presented on the strength, failure strain and modulus of multi-year sea ice under different loading conditions. The effects of ice temperature, porosity, structure, strain rate, confining pressure and sample orientation on the mechanical properties of multi-year sea ice are examined.
    Type of Medium: Series available for loan
    Pages: vi, 89 Seiten , Illustrationen
    Series Statement: CRREL Report 85-16
    Language: English
    Note: CONTENTS Abstract Preface Introduction Field sampling program Site selection and description Coring procedures Core logging procedures Shipping and storage of ice samples Ice description Salinity and density Structure Constant-strain-rate compression tests Test variables Uniaxial compressive strength Strength and structure Strength and porosity Residual compressive strength Failure strain Initial tangent modulus Constant-strain-rate uniaxial tension tests Test variables Uniaxial tensile strength Failure strains Initial tangent modulus Constant-strain-rate triaxial tests Equipment Test variables Synthane end caps Triaxial strength Failure strains Initial tangent modulus Effect of sinthane end caps on results Constant-load compression tests Test variables Test results Conclusions Literature cited Appendix A: Ice structure profile of ridge C core Appendix H: Test data Appendix C: Static determination of Young's modulus in sea ice
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  • 4
    Series available for loan
    Series available for loan
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
    Associated volumes
    Call number: ZSP-201-88/13
    In: CRREL Report, 88-13
    Description / Table of Contents: In many sea ice engineering problems the ice sheet has been assumed to be a homogeneous plate whose mechanical properties are estimated from the bulk salinity and average temperature of the ice sheet. Typically no regard has been given to the vertical variation of ice properties in the ice sheet or to the time of ice formation. This paper first reviews some of the mechanical properties of sea ice, including the ice tensile, flexural and shear strengths, as well as the ice modulus. Equations for these properties are given as functions of the ice brine volume, which can be determined from the ice salinity and temperature. Next a numerical, finite difference model is developed to predict the salinity and temperature profiles of a growing ice sheet. In this model ice temperatures are calculated by performing an energy balance of the heat fluxes at the ice surface. The conductive heat flux is used to calculate the rate of ice growth and ice thickness by applying the Stefan ice growth equation. Ice salinities are determined by considering the amount of initial salt entrapment at the ice/water interface and the subsequent brine drainage due to brine expulsion and gravity drainage. Ice salinity and temperature profiles are generated using climatological data for the Central Arctic basin. The predicted salinity and temperature profiles are combined with the mechanical property data to provide mechanical property profiles for first-year sea ice of different thicknesses, grown at different times of the winter. The predicted profiles give composite plate properties that are significantly different from bulk properties obtained by assuming homogeneous plates. In addition the failure strength profiles give maximum strength in the interior of the sheet as contrasted with the usual assumption of maximum strength at the cold, upper ice surface. Surprisingly the mechanical property profiles are only a function of the ice thickness, independent of the time of ice formation.
    Type of Medium: Series available for loan
    Pages: v, 63 Seiten , Illustrationen
    Series Statement: CRREL Report 88-13
    Language: English
    Note: CONTENTS Abstract Preface Introduction Structure Composition Mechanical properties Strength Elastic constants The temperature-salinity model Temperature profiles Salinity profiles Composite plate properties Results Conclusions Literature cited Appendix A: Details of the equations for ice surface temperature and conductive heat flux Appendix B: Calculated profile and bulk properties of an ice sheet of varying thickness Appendix C: Calculated profile and bulk properties of 30- and 91-cm-thick ice sheets
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  • 5
    Call number: ZSP-201-84/9
    In: CRREL Report, 84-9
    Description / Table of Contents: This report presents the results of the first phase of a test program designed to obtain a comprehensive understanding of the mechanical properties of multi-year sea ice from the Alaskan Beaufort Sea. In Phase I, 222 constant-strain-rate uni-axial compression tests were performed on ice samples from ten multi-year pressure ridges to examine the magnitude and variation of ice strength within and between pressure ridges. A limited number of constant-strain-rate compression and tension tests, constant-load compression tests, and conventional triaxial tests were also performed on ice samples from a multi-year floe to provide preliminary data for developing ice yield criteria and constitutive laws for multi-year sea ice. Data are presented on the strength, failure strain, and modulus of multi-year sea ice under different loading conditions. The statistical variation of ice strength within and between pressure ridges is examined, as well as the effects of ice temperature, porosity, structure, strain rate and confining pressure on the mechanical properties of multi-year sea ice.
    Type of Medium: Series available for loan
    Pages: v, 107 Seiten , Illustrationen
    Series Statement: CRREL Report 84-9
    Language: English
    Note: CONTENTS Abstract Preface Introduction Field Sampling Site selection and description Ice sampling procedures Shipping and storage of ice samples Testing Techniques Multi-year Pressure Ridge Tests Ice description Sampling scheme and test variables Uniaxial compressive strength Residual compressive strength Failure strains Initial tangent modulus Statistical Variations in Ice Strength Differences in strength above and below level ice Sources of the variation in strength Shape of the strength histograms Multi-year Floe Ice Tests Ice description Uniaxial compressive strength Constant-load compression tests Constant-strain-rate tension tests Triaxial tests Conclusions Literature Cited Appendix A: Structural profile of a multi-year pressure ridge core Appendix B: Ridge uniaxial compression test data Appendix C: Structural profile of the continuous multi-year floe core Appendix D: Multi-year floe test data
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  • 6
    Series available for loan
    Series available for loan
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
    Associated volumes
    Call number: ZSP-201-84/2
    In: CRREL Report, 84-2
    Description / Table of Contents: Investigations of the in situ complex dielectric constant of sea ice were made using time-domain spectroscopy. It was found that (1) for sea ice with a preferred horizontal crystal c-axis alignment, the anisotropy of polarizing properties of the ice increased with depth, (2) brine inclusion conductivity increased with decreasing temperature down to about -8 C, at which point the conductivity decreased with decreasing temperature, (3) the DC conductivity of sea ice increased with increasing brine volume, (4) the real part of the complex dielectric constant is strongly dependent upon brine volume but less dependent upon the brine inclusion orientation, (5) the imaginary part of the complex dielectric constant was strongly dependent upon brine inclusion orientation but much less dependent upon brine volume. Because the electromagnetic (EM) properties of sea ice are dependent upon the physical state of the ice, which is continually changing, it appears that only trends in the relationships between the EM properties of natural sea ice and its brine volume and brine inclusion microstructure can be established.
    Type of Medium: Series available for loan
    Pages: vi, 38 Seiten , Illustrationen , 1 Beilage
    Series Statement: CRREL Report 84-2
    Language: English
    Note: CONTENTS Abstract Preface Nomenclature Introduction Dielectric properties of sea ice Time-domain spectroscopy measurement Laboratory measurements Field measurements Analysis of ladder data Conductivity of brine and sea ice Complex dielectric constant of brine and sea ice Discussion and conclusions Literature cited
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  • 7
    Series available for loan
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    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
    Associated volumes
    Call number: ZSP-201-84/8
    In: CRREL Report, 84-8
    Description / Table of Contents: This report describes the equipment and procedures that were used for acquiring, preparing and testing samples of multi-year sea ice. Techniques and procedures are discussed for testing ice samples in compression and tension at constant strain rates and constant loads, as well as in a conventional triaxial cell. A detailed account is given of the application and measurement of forces and dispiacements on the ice test specimens under these different loading conditions.
    Type of Medium: Series available for loan
    Pages: iv, 43 Seiten , Illustrationen
    Series Statement: CRREL Report 84-8
    Language: English
    Note: CONTENTS Abstract Preface Introduction Test material and test specimens Test material Required dimensions for test specimens Acquisition and preparation of specimens Field core sampling Specimen preparation in the laboratory Application of forces and displacements to uniaxial specimens Compression Tension Squareness imperfections Loading devices Universal testing machine Gas actuator for constant load Weight-and-pulley system for constant tension Equipment for triaxial tests Measurement of force and displacement Force Displacement Readouts and recorders Literature cited Appendix A: Phenolic-resin end caps Appendix B: Compliant platens Appendix C: Theoretical factor for converting overall strain to gauge-length strain indumbbell specimens Appci dix D: Items developed but not used in Phase I Appendix E: Use of the Brazil test
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  • 8
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    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
    Associated volumes
    Call number: ZSP-201-83/23
    In: CRREL Report, 83-23
    Description / Table of Contents: The problems associated with measuring stresses in ice are reviewed. Theory and laboratory test results are then presented for a stiff cylindrical sensor made of steel that is designed to measure ice stresses in a biaxial stress field. Loading tests on freshwater and saline ice blocks containing the biaxial ice stress sensor indicate that the sensor has a resolution of 20 kPa and an accuracy of better than 15% under a variety of uniaxial and biaxial loading conditions. Principal stress directions can also be determined within 5 degrees. The biaxial ice stress sensor is not significantly affected by variations in the ice elastic modulus, ice creep or differential thermal expansion between the ice and gauge. The sensor also has a low temperature sensitivity (5 kPa/deg C).
    Type of Medium: Series available for loan
    Pages: 38 Seiten , Illustrationen
    Series Statement: CRREL Report 83-23
    Language: English
    Note: CONTENTS Abstract Preface Introduction Previous work Stress measurements Design considerations Stress sensors Biaxial ice stress sensor Biaxial stress sensor theory Gauge deformation Stresses associated with cylindrical sensors Determination of ice stresses Gauge calibration Evaluation of the biaxial ice stress sensor Temperature sensitivity Biaxial loading test equipment Biaxial loading test results Differential thermal expansion Long-term drift Discussion of test results Conclusions Literature cited
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  • 9
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    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
    Associated volumes
    Call number: ZSP-202-345
    In: Research report / Cold Regions Research and Engineering Laboratory, 345
    Description / Table of Contents: CONTENTS: Abstract. - Preface. - List of symbols. - Introduction. - Previous work. - Experimental design. - The radioisotope 22Na. - Description of apparatus. - Experimental procedure. - Correction of profiles. - Assumptions. - Decay correction. - Boundary correction. - Error analysis. - Results. - Salinity data. - Temperature data. - Growth velocity. - Discussion. - Brine and ice properties. - Brine salinity. - Brine density. - Brine volume. - Brine latent heat of freezing. - Brine viscosity, specific heat, and thermal conductivity. - Ice properties. - Theoretical brine expulsion model. - Continuity equations. - Thermal energy equation. - Simplified brine expulsion equations. - Brine expulsion in NaCl ice. - Results. - Discussion. - Gravity drainage in NaCl ice. - Application of results to natural sea ice. - Effective distribution coefficient. - Previous work. - Experimental procedure and results. - Conclusions. - Literature cited. - Appendix A: Profile correction data. - Appendix B: Program "correct" and sample output. - Appendix C: Tabulation of salinity data. - Appendix D: Tabulation of profile data. - Appendix E: Time-ice thickness equations (Runs 2 and 3). - Appendix F: Tabulation of distribution coefficient data.
    Description / Table of Contents: To obtain a better understanding of the desalination of natural sea ice, an experimental technique was developed to measure sequential salinity profiles of a growing sodium chloride ice sheet. Using radioactive 22Na as a tracer, it was possible to determine both the concentration and movement of the brine within the ice without destroying the sample. A detailed temperature and growth history of the ice was also maintained so that the variation of the salinity profiles could be properly interpreted. Since the experimental salinity profile represented a smoothed, rather than a true salinity distribution, a deconvolution method was devised to restore the true salinity profile. This was achieved without any significant loss of end points. In all respects, the salinity profiles are similar to those of natural sea ice. They have a characteristic C-shape, and clearly exhibit the effects of brine drainage. Not knowing the rates of brine expulsion or gravity drainage, the variation of the salinity profiles during the period of ice growth could be explained by either process. To determine the relative importance of the desalination mechanisms, a theoretical brine expulsion model was derived and compared to the experimental data. As input for the model, equations describing the variation of some properties of NaCl brine with temperature were derived. These included the brine salinity, viscosity, specific heat, thermal conductivity, and latent heat of freezing. The theoretical brine expulsion model was derived by performing mass and energy balances over a control volume of NaCl ice. A simplified form of the model, when compared to the experimental results, indicated that brine expulsion was only important during the first several hours of ice growth, and later became a minor desalination process relative to gravity drainage which continued to be the dominant mechanism for the remainder of the study period (up to 6 weeks). The rate of gravity drainage was found to be dependent on the brine volume and the temperature gradient of the ice. As either the brine volume or temperature gradient was increased, the rate of change of salinity due to gravity drainage increased. The equation commonly used to calculate the effective distribution coefficient (Weeks and Lofgren 1967) was modified and improved by taking brine drainage into account. An expression was also derived to give the distribution coefficient at very low growth velocities.
    Type of Medium: Series available for loan
    Pages: vii, 85 Seiten , Illustrationen
    Series Statement: Research report / Cold Regions Research and Engineering Laboratory 345
    Language: English
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  • 10
    Call number: ZSP-201-87/3
    In: CRREL Report, 87-3
    Description / Table of Contents: This report describes the structural analysis of multi-year sea ice samples that were tested in the first phase of a program designed to obtain a comprehensive understanding of the mechanical properties of multi-year sea ice from the Alaskan Beaufort Sea. Each test specimen is classified into one of three major ice texture categories: granular, columnar, or a mixture of columnar and granular ice. The crystallographic orientation, percent columnar ice, and grain size are then evaluated for the granular and/or columnar ice in the sample. Test results are interpreted with respect to these parameters. The overall composition of multi-year ridges is also considered, based on the extensive field sampling that was done in the program
    Type of Medium: Series available for loan
    Pages: iii, 40 Seiten , Illustrationen
    Series Statement: CRREL Report 87-3
    Language: English
    Note: CONTENTS Abstract Preface Introduction Sample analysis Continuous multi-year ridge core Tested multi-year ridge ice samples Tested multi-year floe ice samples Ice description Uniaxial constant-strain-rate compression tests Uniaxial constant-load compression tests Uniaxial constant-strain-rate tension tests Triaxial constant-strain-rate compression test Conclusions Literature cited Appendix A: Multi-year ridge sample data Appendix B: Multi-year floe sample data
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