Strona 2_redak - Instytut Agrofizyki im. Bohdana DobrzaÅskiego ...
Strona 2_redak - Instytut Agrofizyki im. Bohdana DobrzaÅskiego ...
Strona 2_redak - Instytut Agrofizyki im. Bohdana DobrzaÅskiego ...
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CONTENT<br />
PREFACE ……………………………………………………………………………. 5<br />
BASIC NOTATION …………………………………………………………………. 6<br />
1. INTRODUCTION ………………………………………………………………… 7<br />
2. CONTINUUM MECHANICS APPROACH ……………………………………... 9<br />
2.1. The plastic flow rule …………………………………………………………. 9<br />
2.2. Plastic model with hardening and softening …………………………………. 10<br />
2.3. Elastic-plastic models of Ghaboussi and Momen and of Lade ………………. 14<br />
3. MICROSTRUCTURAL APPROACH. DEM MODELLING ……………………. 17<br />
3.1. Geometric structure of granular medium …………………………………….. 17<br />
3.2. Anisotropy of seed layer ……………………………………………………... 20<br />
3.3. Microstuctural models ……………………………………………………….. 28<br />
3.4. Distinct Element Method ………………………………………………….… 30<br />
3.5. Model of micropolar continuum ……………………………………………... 34<br />
3.6. Localization of shear deformation …………………………………………… 36<br />
4. CLASSIFICATION OF GRANULAR MATERIALS ……………………………. 38<br />
5. DENSITY OF GRANULAR MATERIALS ……………………………………… 40<br />
5.1. Bulk density ………………………………………………………………….. 40<br />
5.2. Density of consolidated material …………………………………………….. 42<br />
6. COMPRESSIBILITY AND ELASTICITY ………………………………………. 43<br />
7. STRENGTH PARAMETERS …………………………………………………….. 50<br />
7.1 Methods and apparatus ……………………………………………………….. 50<br />
7.1.1. Direct shear test ……………………………………………………... 50<br />
7.1.2. Triaxial compression test ……………………………………………. 53<br />
7.2 Factors influencing angle of internal friction of cereals ……………………… 55<br />
7.2.1. Moisture content of the material ………………………………………. 55<br />
7.2.2. Bulk density …………………………………………………………… 56<br />
7.2.3. T<strong>im</strong>e of consolidation …………………………………………………. 57<br />
7.2.4. Method of sample deposition. Anisotropy of packing ……………… 57<br />
7.2.5. Surface properties of particles ………………………………………… 59<br />
7.2.6. Formation of shear bands …………………………………………… 59<br />
7.2.7. Correction of change in sample cross-section area …………………… 62<br />
8. FLOW FUNCTION ………………………………………………………………. 63<br />
9. COEFFICIENT OF FRICTION …………………………………………………... 65<br />
9.1. Theories of dry friction ………………………………………………………. 65<br />
9.2. Exper<strong>im</strong>ental methods ………………………………………………………. 67