Strona 2_redak - Instytut Agrofizyki im. Bohdana DobrzaÅskiego ...

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EC Centre of Excellence AGROPHYSICS Centre of Excellence for Applied Physics in Sustainable Agriculture QLAM-2001-00428 Reviewed by: Prof. Jarosław Frączek ISBN 83-89969-35-1 © Institute of Agrophysics PAS, Lublin 2005 Edition: 180 copies Project of cover: Wanda Woźniak Computer edition: Joanna Sykut Printed by: Alf-Graf, ul. Kościuszki 4, 20-006 Lublin, Poland
3 CONTENT PREFACE ……………………………………………………………………………. 5 BASIC NOTATION …………………………………………………………………. 6 1. INTRODUCTION ………………………………………………………………… 7 2. CONTINUUM MECHANICS APPROACH ……………………………………... 9 2.1. The plastic flow rule …………………………………………………………. 9 2.2. Plastic model with hardening and softening …………………………………. 10 2.3. Elastic-plastic models of Ghaboussi and Momen and of Lade ………………. 14 3. MICROSTRUCTURAL APPROACH. DEM MODELLING ……………………. 17 3.1. Geometric structure of granular medium …………………………………….. 17 3.2. Anisotropy of seed layer ……………………………………………………... 20 3.3. Microstuctural models ……………………………………………………….. 28 3.4. Distinct Element Method ………………………………………………….… 30 3.5. Model of micropolar continuum ……………………………………………... 34 3.6. Localization of shear deformation …………………………………………… 36 4. CLASSIFICATION OF GRANULAR MATERIALS ……………………………. 38 5. DENSITY OF GRANULAR MATERIALS ……………………………………… 40 5.1. Bulk density ………………………………………………………………….. 40 5.2. Density of consolidated material …………………………………………….. 42 6. COMPRESSIBILITY AND ELASTICITY ………………………………………. 43 7. STRENGTH PARAMETERS …………………………………………………….. 50 7.1 Methods and apparatus ……………………………………………………….. 50 7.1.1. Direct shear test ……………………………………………………... 50 7.1.2. Triaxial compression test ……………………………………………. 53 7.2 Factors influencing angle of internal friction of cereals ……………………… 55 7.2.1. Moisture content of the material ………………………………………. 55 7.2.2. Bulk density …………………………………………………………… 56 7.2.3. T<strong>im</strong>e of consolidation …………………………………………………. 57 7.2.4. Method of sample deposition. Anisotropy of packing ……………… 57 7.2.5. Surface properties of particles ………………………………………… 59 7.2.6. Formation of shear bands …………………………………………… 59 7.2.7. Correction of change in sample cross-section area …………………… 62 8. FLOW FUNCTION ………………………………………………………………. 63 9. COEFFICIENT OF FRICTION …………………………………………………... 65 9.1. Theories of dry friction ………………………………………………………. 65 9.2. Exper<strong>im</strong>ental methods ………………………………………………………. 67
Page 4 and 5: 4 9.3. Factors influencing the coef
Page 6 and 7: 6 BASIC NOTATION c - cohesion [kPa]
Page 8 and 9: 8 Numerous granular materials when
Page 10 and 11: 10 the tensor of plastic strain inc
Page 12 and 13: 12 Fig. 2.1. Yield curves with comp
Page 14 and 15: 14 Stable or unstable behaviour of
Page 16 and 17: 16 In turn, the model of Lade, also
Page 18 and 19: 18 same porosity need not have iden
Page 20 and 21: 20 where: A = ∫ E( β) sin βdβ
Page 22 and 23: 22 (β = 0 o ), positioning the out
Page 24 and 25: 24 grain was poured into the mould
Page 26 and 27: 26 axes of the ellipse characterizi
Page 28 and 29: 28 [176] for the determination of p
Page 30 and 31: 30 A different approach to the desc
Page 32 and 33: 32 where: I - moment of inertia, k
Page 34 and 35: 34 a) b) f s f s m M f n f n Contac
Page 36 and 37: 36 The micropolar model yields resu
Page 38 and 39: 38 Fig. 3.17. Model of shear band f
Page 40 and 41: 40 In the case of agricultural mate
Page 42 and 43: 42 5.2. Density of consolidated mat
Page 44 and 45: 44 (cereal grain, sand, soil), the
Page 46 and 47: 46 Multiple wetting and drying of g
Page 48 and 49: 48 vertical pressure within the ran
Page 50 and 51: 50 of the curve defined by A, where
Page 52 and 53:
52 6. Vertical consolidation refere
Page 54 and 55:
54 poured into the box without vibr
Page 56 and 57:
56 7.2.2. Bulk density Stress-strai
Page 58 and 59:
58 near the box wall and lifted alo
Page 60 and 61:
60 and the upper boundary was 18.5
Page 62 and 63:
62 A -1 5 -1 0 -5 1 0 5 -5 5 1 0 1
Page 64 and 65:
64 Fig. 8.2. Yield locus and effect
Page 66 and 67:
66 in such a way that friction woul
Page 68 and 69:
68 a) b) µ = tg ϕw ϕ w c) d) e)
Page 70 and 71:
70 9.3. Factors influencing the coe
Page 72 and 73:
72 galvanized steel received from d
Page 74 and 75:
74 9.3.4. Velocity of sliding Becau
Page 76 and 77:
76 1+ sinϕ k = . 1 − sinϕ (10.3
Page 78 and 79:
78 N ϕ VLQϕ 3UHVVXUHUDWLRN
Page 80 and 81:
80 10.4.1. Friction force mobilizat
Page 82 and 83:
82 10.4.3. Moisture content With in
Page 84 and 85:
84 Table 10.1. Measured (k s ) and
Page 86 and 87:
86 conventional engineering analyse
Page 88 and 89:
88 a, b - product-dependent coeffic
Page 90 and 91:
90 also be performed as a function
Page 92 and 93:
92 reliable processing and stable v
Page 94 and 95:
94 unconfined yield strength to pow
Page 96 and 97:
96 The Chute Index (CI) is recommen
Page 98 and 99:
98 obtained the maximum deviation o
Page 100 and 101:
100 efficient flow control using op
Page 102 and 103:
102 In the field of experimental in
Page 104 and 105:
104 22. Britton M.G., Moysey E.B.:
Page 106 and 107:
106 69. Horabik J., Rusinek R.: Pre
Page 108 and 109:
108 114. Morland L.W., Sawicki A.,
Page 110 and 111:
110 158. 6WSQLHZVNL$ Influence of m
Page 112 and 113:
112 16. APPENDIX - Physical Propert
Page 114 and 115:
114 16.2. Density and porosity Tabl
Page 116 and 117:
116 Table 16.7. Mean values (±St.
Page 118 and 119:
Page 120 and 121:
Page 122 and 123:
Page 124 and 125:
Page 126 and 127:
126 Table 16.16. Cont. 1 2 3 4 Icin
Page 128 and 129:
Page 130 and 131:
Page 132 and 133:
Page 134 and 135:
Page 136 and 137:
136 Table 16.25. Cont. 1 2 3 4 Icin
Page 138 and 139:
Page 140 and 141:
140 Table 16.29. Cont. Table sugar
Page 142 and 143:
Page 144 and 145:
144 Table 16.35. Mean values (± St
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