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- Alm, Ove, et al.
(författare)
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Microstructures and mechanical characteristics of the Tännäs augen gneiss, Swedish Caledonides
- 1980
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Ingår i: Geologiska föreningens i Stockholm förhandlingar. - : Informa UK Limited. - 0016-786X. ; 102:4, s. 319-334
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Tidskriftsartikel (refereegranskat)abstract
- The mechanical behaviour, microstructure and substructure of the classic Tannas augen gneiss of the Swedish Caledonides are presented. Progressive deformation of granodiorite to augen gneiss and mylonite is shown to take place in an isochemical environment with redistribution of megacrysts to surrounding matrix. Experimental deformation of natural rocks from the Tannas Augen Gneiss Nappe has been carried out in the temperature range of 20-600oC and under confining pressure of 100-700MPa. The highest strength found is for the fine-grained mylonite. The augen of the gneiss show brittle behaviour under all test conditions, and temperature has a limited effect on the ultimate strength of the matrix of the augen gneiss. Microstructures have been analysed by means of optical microscopy and transmission electron microscopy. The progressive deformation is brought about by dislocation glide and dislocation creep. Subgrain formation, recrystallization and straining of new grains are observed at all stages of the progressive deformation of the matrix while the augen behavior is brittle
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| 2. |
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| 3. |
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| 4. |
- Alm, Ove
(författare)
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Experimental deformation of granitic rocks
- 1981
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Ingår i: Geologiska Föreningen i Stockholm Förhandlingar. - : Informa UK Limited. - 0016-786X. ; 103:1, s. 134-136
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Tidskriftsartikel (refereegranskat)
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| 5. |
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| 6. |
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| 7. |
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| 8. |
- Alm, Ove
(författare)
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Mechanical testing of powders and powder compacts
- 1983
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Ingår i: Scandinavian journal of metallurgy. - 0371-0459 .- 1600-0692. ; 12:6, s. 302-311
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Tidskriftsartikel (refereegranskat)abstract
- Results from standard triaxial, uniaxial and bending tests are presented. Triaxial tests were performed at pressures in the range 0-200 MPa. Both initial loose powder samples and cylindrical precompacted specimens were studied under hydrostatic conditions. Most of the total volume compaction occurred at pressures below 10 MPa. Triaxial tests with superimposed axial loads showed no softening despite a 30% shortening of the length of specimens which initially were 60 mm long. Specimens deformed in triaxial tests showed a higher density and a higher uniaxial compressive strength than specimens compacted under hydrostatic conditions.
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| 9. |
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| 10. |
- Lindqvist, Per-Arne, et al.
(författare)
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Indentation fracture development in rock continuously observed with scanning electron microscope
- 1984
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Ingår i: International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts. - : Elsevier BV. - 0148-9062 .- 1879-2073. ; 21:4, s. 165-182
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Tidskriftsartikel (refereegranskat)abstract
- Indentation tests observed in a scanning electron microscope (SEM) using a sharp and a truncated wedge in three different rocks are reported. By indenting at the edge of one surface and scanning the neighboring surface perpendicular to the direction of loading, it was possible to study the continuous development of cracks throughout the tests. Cracks initiated mainly at the edge and corners of wedges but initiation in the interior of the rock was also observed. Crack initiation and crack paths observed in all rocks are in good agreement with assumed theoretical elastic stress fields, although the nature of the fractures is greatly influenced by different material properties such as grain size, cleavage planes and grain bonding. Recorded force-displacement curves allowed distinction between different fracture processes.
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