Fracture of Lake and Sea Ice

Fracture of Lake and Sea Ice

Author: Wilford Frank Weeks

Publisher:

Published: 1969

Total Pages: 92

ISBN-13:

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The increased activity in cold regions has made a thorough understanding of fracture in lake and sea ice quite desirable, inasmuch as this information has application to a number of problems of geophysical as well as engineering importance. This survey starts with a discussion of the structure of ice I and the macro- and microstructure of sea and lake ice as well as their chemistry and phase relations. Recent work on the direct observation of dislocations as well as the formation of cracks in ice is summarized. Formal ice-brine-air models for analyzing variations in ice strength are also reviewed. The results of the different types of tests are discussed and compared (compressive, indentation, direct and ring-tension, small beam flexure and in situ cantilevers and simple beams, shear, and impact). Scale effects are considered as well as the rapid strength deterioration experienced by ice sheets in the spring. Finally, a number of recommendations are made concerning future research in this field. (Author).


The Mechanics of Ice

The Mechanics of Ice

Author: John W. Glen

Publisher:

Published: 1975

Total Pages: 56

ISBN-13:

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This monograph summarizes knowledge of the mechanics of ice. It is concerned principally with the effect of stress on the mechanical properties of ice, including elasticity, anelasticity, sound propagation, plastic deformation and creep in single crystals and in polycrystalline ice, fracture, and recrystallization and grain growth that accompanies plastic deformation. The monograph also includes a comprehensive bibliography.


Austenitic Steels at Low Temperatures

Austenitic Steels at Low Temperatures

Author: T. Horiuchi

Publisher: Springer Science & Business Media

Published: 2012-12-06

Total Pages: 384

ISBN-13: 1461337305

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The need for alternate energy sources has led to the develop ment of prototype fusion and MHD reactors. Both possible energy systems in current designs usually require the use of magnetic fields for plasma confinement and concentration. For the creation and maintenance of large 5 to 15 tesla magnetic fields, supercon ducting magnets appear more economical. But the high magnetic fields create large forces, and the complexities of the conceptual reactors create severe space restrictions. The combination of re quirements, plus the desire to keep construction costs at a mini mum, has created a need for stronger structural alloys for service at liquid helium temperature (4 K). The complexity of the required structures requires that these alloys be weldable. Furthermore, since the plasma is influenced by magnetic fields and since magnet ic forces from the use of ferromagnetic materials in many configur ations may be additive, the best structural alloy for most applica tions should be nonmagnetic. These requirements have led to consideration of higher strength austenitic steels. Strength increases at low temperatures are achieved by the addition of nitrogen. The stability of the austenitic structure is retained by adding manganese instead of nickel, which is more expensive. Research to develop these higher strength austenitic steels is in process, primarily in Japan and the United States.