The effects of heat pretreatment and ambient gas (air and vacuum) on selected properties of the polycarbonate sheet have been studied. Changes in tensile properties as functions of heat pretreatment temperature (up to 16OOC) and strain rate (wide range of 1.7 X -13.1 m/sec = 0.29 -2.3 x 104 %/sec) w
Strain rate, temperature, and sample size effects on compression and tensile properties of frozen sand
โ Scribed by Richard A. Bragg; O.B. Andersland
- Publisher
- Elsevier Science
- Year
- 1981
- Tongue
- English
- Weight
- 628 KB
- Volume
- 18
- Category
- Article
- ISSN
- 0013-7952
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โฆ Synopsis
Selection of material properties for use in design of frozen earth structures has been a limiting factor for some field applications. In particular, the mechanical properties governing the behavior of a frozen soil structure subjected to bending stresses are of interest. The effects of strain rate, temperature, and sample size on the compressive and tensile properties of frozen silica sand have been determined experimentally using uniaxial compression and split cylinder tests. Data included on the initial tangent modulus, compressive strength, failure strains, and tensile strength help delineate some limitations of available test procedures. Failure modes for various test conditions are described.
Data analysis shows that the initial yield stress, the compressive peak strength, and the initial tangent modulus increase with decreasing temperatures and increasing strain rates. Tensile strengths from split cylinder tests appear to be independent of deformation rates. Uniaxial compressive strengths decreased slightly and the initial tangent modulus increased with increasing sample diameter (constant length to diameter ratio). Deformation and failure modes changed from a plastic to a brittle behavior when strain rates were increased from low to high values. Larger failure strains at slower strain rates (more time available) appear to be a result of pressure melting, water migration and refreezing, permitting more particle readjustments before development of the peak strength. Observations on failure strains suggest limiting values for design situations.
๐ SIMILAR VOLUMES
Curves are presented showing the ultimate tensile strength of molded H4LM graphite in the transverse orientation ("with the grain") as a function of temperature, for tests made in vacuum and in static helium at nominal engineering strain rates of 0.005, 0.5 and 2.0/min. Temperature ranges considered