sin αst

More documents

Recommendations

Info

E Structural analysis of blades This appendix contains a general description of the material used for the blades, followed by a statement of its mechanical properties. It further encloses a verification of the structural integrity of blades through finite element analysis. E.1 Material description For purpose of analysis the engineering properties of pinus taeda are used. This type of wood is commonly known as loblolly pine, native to the South-eastern United States and widely available in regions such as Africa and South East Asia [51]. It is therefore a likely material candidate in the countries targeted by the present wind turbine design. For future designs the selected wood may be substituted by other types of wood, e.g. dif- ferent wood species, jointed wood, glued laminated wood or wood composites. Substitu- tion requires that the new material has equal or greater strength and stiffness, and that proper consideration is taken to manufacturing issues, described in section 6.2.3. The mechanical properties presented in the following section assume that the blades are produced from wood pieces that are termed clear and straight grained, i.e. considered homogeneous within wood mechanics. This implies that the wood has growth rings that occur in consistent patterns and that it does not contain characteristics such as knots, cross grain and splits. 147
LIST OF ATTACHMENTSSTRUCTURAL ANALYSIS OF BLADES Orthotropy Wood may be described as an orthotropic material, as it has unique and independent properties in the three mutually perpendicular directions. The longitudinal axis is parallel to the grain (fibre), the radial axis is normal to the growth rings and the tangential axis is tangent to the growth rings. The axes are shown on figure E.1 and designated with coordi- nates that are valid when the blade is manufactured from the directions given in section 6.2.3. 148 Figure E.1: Principal axes of wood with respect to fibre direction and growth rings Moisture content Wood is also a hygroscopic material, i.e. a material that takes in moisture from the surrounding environment. The moisture content MC is the amount of water, in any of its states, contained in wood. It is usually expressed as a weight percentage: Where mwater is the mass of water in the wood and mwood is the mass of oven-dry wood. MC includes water or water vapour absorbed into cell walls and free water within the hollow centre of the cells. The amount of water vapour wood absorbs depends on the relative humidity (RH) of the surrounding air. If wood is stored at 0% RH, the MC will eventually approach 0%. If wood is stored at 100% RH, the MC will eventually reach fibre saturation (approximately 30% moisture). This moisture relationship has an important influence on wood properties and performance. In general most mechanical properties will decrease with increase in moisture content [30, p. 16-6]. mwater MC = mwood (E.1)
Page 1 and 2:
WIND TURBINE DESIGN
Page 3 and 4:
ABSTRACT At the request of the Engi
Page 5 and 6:
CONTENTS 1 Introduction ...........
Page 7 and 8:
E Structural analysis of blades ...
Page 9 and 10:
INTRODUCTION members. Today EWB-DK
Page 11 and 12:
INTRODUCTION Figure 1.2: Left pictu
Page 13 and 14:
INTRODUCTION 6
Page 15 and 16:
PROBLEM STATEMENT reconfigured with
Page 17 and 18:
PROBLEM STATEMENT 10
Page 19 and 20:
METHODOLOGY Figure 3.1: Flow chart
Page 21 and 22:
METHODOLOGY 14 3.1 Calculation meth
Page 23 and 24:
CONCEPTUALISATION the kinetic wind
Page 25 and 26:
CONCEPTUALISATION Figure 4.3: (a) D
Page 27 and 28:
CONCEPTUALISATION issues due to tur
Page 29 and 30:
CONCEPTUALISATION 22 Figure 4.8: Ty
Page 31 and 32:
CONCEPTUALISATION � Darrieus 24 F
Page 33 and 34:
CONCEPTUALISATION 26 Figure 4.13: G
Page 35 and 36:
CONCEPTUALISATION Figure 4.14: Powe
Page 37 and 38:
CONCEPTUALISATION 30 ID Requirement
Page 39 and 40:
CONCEPTUALISATION most suitable sol
Page 41 and 42:
CONCEPTUALISATION The embodiment de
Page 43 and 44:
DESIGN PRESENTATION The main dimens
Page 45 and 46:
DESIGN PRESENTATION The design prop
Page 47 and 48:
DESIGN PRESENTATION The background
Page 49 and 50:
ROTOR 42 6.1 Number of blades Moder
Page 51 and 52:
ROTOR 44 Figure 6.4: Blade design s
Page 53 and 54:
ROTOR Table 6.3 provides a material
Page 55 and 56:
ROTOR Figure 6.7 displays the lift
Page 57 and 58:
ROTOR Figure 6.9: Rotor power outpu
Page 59 and 60:
ROTOR 6.2.3 Manufacturing During th
Page 61 and 62:
ROTOR 54 The three sides of the tem
Page 63 and 64:
ROTOR When the carving process is f
Page 65 and 66:
ROTOR 58 Figure 6.17: Blade attachm
Page 67 and 68:
ROTOR 60 Figure 6.19: Rotor power o
Page 69 and 70:
ROTOR 62 Figure 6.22: Efficiency
Page 71 and 72:
ROTOR sidering the output from the
Page 73 and 74:
ROTOR 66
Page 75 and 76:
GENERATOR AND ELECTRICAL SYSTEM 68
Page 77 and 78:
GENERATOR AND ELECTRICAL SYSTEM The
Page 79 and 80:
GENERATOR AND ELECTRICAL SYSTEM Fig
Page 81 and 82:
GENERATOR AND ELECTRICAL SYSTEM 74
Page 83 and 84:
YAW AND FURLING For an upwind wind
Page 85 and 86:
YAW AND FURLING (16), which are bol
Page 87 and 88:
YAW AND FURLING 80 8.2 Furling syst
Page 89 and 90:
YAW AND FURLING 82 8.3 Summary The
Page 91 and 92:
TOWER Concrete tower 84 Figure 9.1:
Page 93 and 94:
TOWER 86 Figure 9.4: Turbulent air
Page 95 and 96:
TOWER Figure 9.7 shows the tower ba
Page 97 and 98:
TOWER models [41, p. 111]. Under ce
Page 99 and 100:
ALTERNATIVE BLADE DESIGN 92 10.1 Ai
Page 101 and 102:
ALTERNATIVE BLADE DESIGN 94 10.3 Su
Page 103 and 104: DESIGN EVALUATION 96 6 W Low-cost m
Page 105 and 106: DESIGN EVALUATION Weaknesses 1) The
Page 107 and 108: FURTHER DEVELOPMENT � Foundation
Page 109 and 110: FURTHER DEVELOPMENT 102
Page 111 and 112: CONCLUSION proposal is highly flexi
Page 113 and 114: NOMENCLATURE Abbreviation Descripti
Page 115 and 116: NOMENCLATURE Lgs Distance between u
Page 117 and 118: NOMENCLATURE 110
Page 119 and 120: BIBLIOGRAPHY [14] Magenn Power Inc.
Page 121 and 122: BIBLIOGRAPHY [53] H. J. Larsen, H.
Page 123 and 124: LIST OF ATTACHMENTSBASIS FOR CALCUL
Page 139 and 140: LIST OF ATTACHMENTSROTOR THEORY Thi
Page 141 and 142: LIST OF ATTACHMENTSROTOR THEORY 134
Page 143 and 144: LIST OF ATTACHMENTSROTOR THEORY Cho
Page 145 and 146: LIST OF ATTACHMENTSROTOR THEORY 138
Page 147 and 148: LIST OF ATTACHMENTSROTOR DESIGN TOO
Page 149 and 150: LIST OF ATTACHMENTSROTOR DESIGN TOO
Page 151 and 152: LIST OF ATTACHMENTSAIRFOIL With the
Page 153: LIST OF ATTACHMENTSAIRFOIL Complete
Page 157 and 158: LIST OF ATTACHMENTSSTRUCTURAL ANALY
Page 191 and 192: LIST OF ATTACHMENTSBLADE ATTACHMENT
Page 197 and 198: LIST OF ATTACHMENTSSTRUCTURAL VERIF
Page 203 and 204: LIST OF ATTACHMENTSTOWER ANALYSIS T
Page 205 and 206:
LIST OF ATTACHMENTSTOWER ANALYSIS T
Page 207 and 208:
LIST OF ATTACHMENTSTOWER ANALYSIS T
Page 209 and 210:
LIST OF ATTACHMENTSFURLING AND YAW
Page 211 and 212:
Page 213 and 214:
Page 215 and 216:
Page 217 and 218:
Page 219 and 220:
Page 221 and 222:
LIST OF ATTACHMENTSALTERNATIVE AIRF
Page 223 and 224:
Page 225 and 226:
Page 227 and 228:
Page 229 and 230:
Page 231:
LIST OF ATTACHMENTSCOMPLIANCE WITH
show all

sin αst

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?