Aluminium Design and Construction John Dwight

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Table 6.2 HAZ-extent parameters for a single straight MIG weld Rule P: A z is put equal to the relevant value in Table 6.2, namely that which equation (6.6) would give when w=w 1 =8 mm. Rule Q: Dimension s is taken equal to the appropriate value in Table 6.2 (proportional to the weld size). 3. Big welds (w 20 mm). The reasoning in this range is that each pass has a ‘zone of influence’ as typically shown in Figure 6.12, which can be related to Rosenthal’s three-dimensional heat-flow case (Figure 6.7). The radius s of this zone depends on the alloy type and the level of thermal control. Table 6.2 gives proposed values of s pessimistically based on a deposit size of 45 mm 2 per pass. The nominal extent of the overall HAZ is constructed by taking the envelope of the zones of influence for all the passes. This is achieved by drawing a series of lines, as shown, each distant s from the relevant welded surface, arcs being replaced by square corners. Figure 6.12 Assumed extent of nominal HAZ at a large multi-pass weld, showing ‘zone of influence’ for one of the passes. Copyright 1999 by Taylor & Francis Group. All Rights Reserved.
Figure 6.13 Predicted area (A z ) of nominal HAZ, comparison of RD method and one-inch rule. RD method: N=normal thermal control; S=strict thermal control. One-inch rule: curve 1 assumes arcs; curve 2 assumes square corners. 6.5.7 Variation of HAZ-extent with weld size The upper plot in Figure 6.13 shows how the area A z of the nominal HAZ, as predicted in Section 6.5.6, varies with size for a long straight fillet weld (MIG) of typical geometry at a joint in 6xxx-series plate. Two curves (N, S) are plotted, corresponding to normal and strict thermal control. On curve N, a hatched area appears in the region t < 8 mm to indicate how A z is affected by deposit control (�=1.0–1.2, see Section 6.5.5). For curve S, which relates to strict thermal control, it is assumed that the deposit control would also be strict (�=1). Note that, when t < 8 mm, curve S is valid even if strict thermal control has not been specified, provided the joint is far enough away from other joints to count as ‘isolated’. Comment is needed on the fact that there is a region on each curve in which A z is shown constant and not going up with weld size. Referring to either curve, the point defined by t (= w) =8 mm represents the largest Copyright 1999 by Taylor & Francis Group. All Rights Reserved.
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Aluminium Design and Construction C
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First published 1999 by E & FN Spon
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2.2.1 Rolling mill practice 2.2.2 P
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5 Limit state design and limiting s
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8.2.6 Use of interpolation for semi
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10.3.2 Inertias for a section with
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Preface Aluminium is easily the sec
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List of symbols The following symbo
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uu, vv principal axes w effective s
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1.1.3 The industrial metal It is on
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where A is the section area (mm 2 )
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1.3.1. The good points about alumin
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Deflection Because of the lower mod
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1.4.4 Establishment of the alloys I
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1.5.2 New technology Most of alumin
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large span, where self-weight is a
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These tend to be in all-aluminium c
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Close-up of the M-dec system, which
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Aluminium glazing system for commer
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Nat West Media Centre, Lords Cricke
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The main requirements for the produ
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in which t and w are in mm. These a
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Figure 2.1 Extrusion process (direc
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Figure 2.2 Typical extrusion die. t
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Figure 2.6 ‘Semi-hollow’ profil
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especially the stronger alloys in t
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Figure 2.9 Conventional profiles. 2
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2.4 TUBES By tubes we mean hollow s
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CHAPTER 3 Fabrication 3.1 PREPARATI
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Figure 3.1 Alternative designs for
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Figure 3.2 Thread insert. a coil-sp
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3.3 ARC WELDING 3.3.1 Use of arc we
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adjusted. The technique is claimed
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For welds of minimum or fatigue qua
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Figure 3.5 Friction-stir welding: s
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are, and the designer/fabricator mu
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cartridge, and mixing takes place a
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3.7.4 Painting Alloys having durabi
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Where a range is given, as for the
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will be only slightly above that fo
Page 81 and 82: heating the metal to a temperature
Page 83 and 84: Table 4.4 Characteristics of differ
Page 85 and 86: softening in the heat-affected zone
Page 87 and 88: 60 alloys, are: BSEN.485 plate and
Page 89 and 90: Firure 4.3 Nominal composition and
Page 91 and 92: popular alloys in the series are: 6
Page 93 and 94: Figure 4.6 Variation of tensile str
Page 95 and 96: undercarriages of aircraft. They ar
Page 97 and 98: Figure 4.11 Minimum stress-strain c
Page 99 and 100: AC.51400 This is another non-heat-t
Page 101 and 102: times that of the actual pits) prod
Page 103 and 104: The severity of bimetallic corrosio
Page 105 and 106: Nominal loading. Nominal loads are
Page 107 and 108: 2. Material factor (� m ). In the
Page 109 and 110: design does not, because stress at
Page 111 and 112: Table 5.2 Summary of limiting stres
Page 113 and 114: Figure 5.4 Plastic strain at workin
Page 115 and 116: example, a reduced value might be t
Page 117 and 118: The parameter � depends purely on
Page 119 and 120: CHAPTER 6 Heat-affected zone soften
Page 121 and 122: area of softening. With 7xxx-type m
Page 123 and 124: Figure 6.3 Typical hardness plots a
Page 125 and 126: 6.4 SEVERITY OF HAZ SOFTENING 6.4.1
Page 127 and 128: Figure 6.6 Categories of welded joi
Page 129 and 130: Figure 6.10 One-inch rule, extent o
Page 131: e allowed for in design by replacin
Page 135 and 136: Figure 6.15 Overlapping HAZs. nomin
Page 137 and 138: In determining A zp , an appropriat
Page 139 and 140: failure plane in the HAZ, close to
Page 141 and 142: With MIG welding, an electrode-posi
Page 143 and 144: CHAPTER 7 Plate elements in compres
Page 145 and 146: (a) Compression member elements The
Page 147 and 148: Table 7.1 Classification of element
Page 149 and 150: Figure 7.4 Slender internal element
Page 151 and 152: Figure 7.7 shows curves of � ° p
Page 153 and 154: (7.9a) (7.9b) The strain gradient c
Page 155 and 156: (through the centroid) for ß S . F
Page 157 and 158: Figure 7.13 Outstands under strain-
Page 159 and 160: Figure 7.15 Reinforced elements. Th
Page 161 and 162: Figure 7.18 Stiffener location for
Page 163 and 164: Figure 7.20 Slender reinforced inte
Page 165 and 166: CHAPTER 8 Beams 8.1 GENERAL APPROAC
Page 167 and 168: 8.2.2 Section classification The di
Page 169 and 170: that for the gross section. It woul
Page 171 and 172: the usual manner. Line 1 in the fig
Page 173 and 174: 1. Fully compact sections. The limi
Page 175 and 176: Figure 8.8 Transverse and longitudi
Page 177 and 178: 8.3.4 Shear resistance of bars and
Page 179 and 180: Figure 8.12 Tension-field action. i
Page 181 and 182: Figure 8.14 Moment/shear interactio
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depending on the estimated degree o
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where a is the stiffener spacing an
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plates (if fitted), p v =limiting m
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ending moment diagram. Two cases ar
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Figure 8.23 Sections covered in Tab
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where: I yy , I vv =inertia about m
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post (Section 8.6.4) or by some oth
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Figure 8.26 Components of deflectio
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9.1.2 Classification of the cross-s
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hole. Alternatively, it might fail
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Figure 9.2 Limiting stress p b for
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The determination of l involves a c
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Figure 9.6 Monosymmetric section. I
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Figure 9.9 Limiting stress p b for
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where s=� s /� t s =slenderness
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Figure 9.11 Type-R sections covered
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Figure 9.14 Four standardized profi
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9.7.2 Secondary bending in trusses
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Table 9.5 Necessary checks for memb
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Figure 9.18 Axial load with biaxial
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1. Tension members. The localized f
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Figure 10.1 Symmetric plastic bendi
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We now turn to monosymmetric sectio
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distance of its centroid from the n
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Figure 10.6 Elements of sections. I
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10.3.3 Product of inertia The produ
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Usually the conditions are such as
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Table 10.2 Torsion constant. Factor
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Figure 10.12 Warping. Conventional
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where b, t=element width and thickn
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10.5.3 Evaluation of warping When t
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For sections where the position of
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(10.31) where: e=distance that S li
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10.5.9 Asymmetric sections Before s
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CHAPTER 11 Joints This chapter cons
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the use of limiting stresses taken
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and the summation is made for all t
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Figure 11.3 Interaction diagram for
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k in order to give a fair compariso
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3. The design is satisfactory if fo
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When the method of surface preparat
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11.3.3 Weld force arising In many c
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Table 11.6 Limiting stress p w (N/m
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where p a =limiting stress for unwe
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Figure 11.11 Interaction diagram fo
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Manufacturers of structural adhesiv
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11.4.6 Creep Shear strength figures
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Figure 11.15 Effect of glue-line th
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Table 11.7 and Figure 11.17 provide
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11.4.11 Resistance calculations for
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high value reflects the various unc
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therefore usually presented in term
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For example: The loading spectrum i
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act on the structure. However, BS.8
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Figure 12.4 Crack propagation: (a)
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12.5 CLASSIFICATION OF DETAILS 12.5
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i.e. a joint extending in the same
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when the design life is low or when
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Methods (2) and (3) are difficult t
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it reverts to line 1. The slope s o
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Aluminium Design and Construction John Dwight

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