A History of Research and a Review of Recent Developments

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Projectile damage to metal structures 173 Figure 7.23 Damage type regime diagram for 0.30 calibre armoured piercing round impacting aluminium (from Avery et al., ref. 7.59). Figure 7.24 Variation of damage size with projectile velocity (from Avery et al., ref. 7.59).
174 Penetration and fragmentation projectile speed do not produce a significant change in damage size. The maximum lateral damage is a circle of radius 6 metres, when the impact velocity is just over 1000 feet/sec. Damage prediction techniques for fragments have only been properly developed for high-velocity compact fragments of low density, typical of impacts from surface/air missiles or high explosive projectiles. An expression proposed by Avery, Porter and Lauzze is: (7.29) where L is the lateral damage size in inches; θ is the impact angle measured between the flight path and a normal to the target surface; D is the maximum projected frontal dimension of the fragment and t is the target thickness in inches. 7.5 FRAGMENTATION Fragmentation was discussed in the previous section (7.4) in relation to the breakup of the casing of conventional bombs, but the history of fragmentation analysis is an interesting field in its own right. As before, students of the subject are indebted to Christopherson [7.12], who dealt with advances in fragmentation prediction during the Second World War. In 1943 Mott produced three research papers for the UK Armament Research Department which included the theoretical treatment of shell fragmentation (refs [7.60] to [7.62] inclusive). Mott argued that the number of fragments (N) between mass W and W+dW should be given by (7.30) where M=W 1/2 and M A, B are constants for a given weapon. B was related to the total fragmenting weight, W 0, by the equation , and the parameter M A was given by M A=Gt 5/6 d 1/3 (1+t/d), where t=thickness of casing (in) and d is the internal diameter (in). Experiments showed that for a TNT filling inside a casing of British Shell Steel (carbon content approximately 0.4 to 0.5%), G=0.3. The fragment weights were measured in ounces. It was pointed out by Christopherson that equation (7.30) and the formula for M A were incompatible, but both had experimental support. The limited range of weapons that could be examined by Mott’s theory was a greater problem, and this was overcome by Payman [7.63]. His formula related the weight of fragments (W) each of weight greater than w, to W 0 by the equation –cw=log 10 W/W 0 , (7.31) where the fragmentation parameter (c) was given by c=Kt –2.45 d –0.55 . The coefficient K depended on the nature of the casing steel and the type of explosive.
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EXPLOSIVE LOADING OF ENGINEERING ST
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Explosive Loading of Engineering St
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Contents Preface vii Acknowledgemen
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Preface A long time ago I walked ov
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Acknowledgements The reports from w
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xii Notation m mass of projectile m
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xiv Notation Q work done during exp
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Introduction Explosions can threate
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Introduction xix Bertram Hopkinson
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Introduction xxi in the seventeenth
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Introduction xxiii own versions of
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Introduction xxv indoor shelters an
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Introduction xxvii explosions/ stru
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Introduction xxix particularly dama
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Introduction xxxi but the feeling i
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2 The nature of explosions propelli
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4 The nature of explosions or rathe
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6 The nature of explosions ogive, a
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8 The nature of explosions mass, an
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10 The nature of explosions Figure
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12 4 lb cylinders, TNT, 3.75 lb sph
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14 The nature of explosions As Figu
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16 The nature of explosions of the
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18 1.4 THE DECAY OF INSTANTANEOUS O
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20 The nature of explosions Figure
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22 The nature of explosions where I
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24 sometimes written in psi as The
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26 The nature of explosions 1.20 Ki
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28 The detonation of explosive char
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50 Figure 2.18 Radius/time curve of
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54 and 50%, rather than by a factor
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3 Propellant, dust, gas and vapour
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Dust explosions 61 as the period 19
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Gas explosions 63 reported by Palme
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Gas explosions 65 workings in very
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Vapour cloud explosions 67 the leak
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References 69 in Los Angeles Harbou
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4 Structural loading from distant e
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Uniformly distributed pressures 73
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Table 4.1 Loading/time relationship
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Loading/time relationships 77 overp
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Loading/time relationships 79 side
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Loads on underground structures 81
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Loads on underwater structures 87 c
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References 89 4.12 Allgood, J. (197
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92 Structural loading from local ex
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98 The general empirical equation f
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100 Structural loading from local e
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112 Figure 5.16 Relationship betwee
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120 Pressure measurement and blast
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Page 175 and 176: 142 Penetration and fragmentation r
Page 177 and 178: 144 Penetration and fragmentation p
Page 179 and 180: 146 Penetration and fragmentation w
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Page 183 and 184: 152 Penetration and fragmentation F
Page 185 and 186: 152 Penetration and fragmentation n
Page 191 and 192: 158 Figure 7.16 Penetration simulat
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Page 197 and 198: 164 Table 7.1 Penetration and fragm
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Page 201 and 202: 168 Penetration and fragmentation I
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Page 213 and 214: 180 Penetration and fragmentation 7
Page 215 and 216: 182 Penetration and fragmentation 7
Page 217 and 218: 184 The effects of explosive loadin
Page 221 and 222: 188 Table 8.1 It is worth noting th
Page 233 and 234: 200 Table 8.5 The effects of explos
Page 249 and 250: 216 Response, safety and evolution
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224 In the log-normal distribution
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226 Response, safety and evolution
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228 Response, safety and evolution
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230 Cole, R.H. 46, 48, 53, 55, 99 C
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232 Petry 143 Philip, E.B. 13, 14,
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Subject index Aircraft damage 207 A
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A History of Research and a Review of Recent Developments

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