A History of Research and a Review of Recent Developments

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The detonation of explosive charges
ground that air bursts could be detonated (often the height of a tower). Most
bursts were therefore subject to the effects of reflection. Tests during the Second
World War suggested that the results for pressure and impulse were much
more scattered than for air bursts, but nevertheless a most useful data collection
was undertaken in 1946 by Kennedy [1.11]. This work was in connection
with the decision of the US National Defence Research Council to produce an
authoritative report on the Effects of Impact and Explosion, and Kennedy
contributed the second chapter on ‘Explosions and explosives in air’. This
was a historically valuable report, although the data was obtained from tests
with relatively undeveloped instrumentation.
Kennedy’s summary of results for the pressure-distance relationship in ground
burst tests is shown in Figure 2.2, taken from ref. [1.11], and his summary of
the impulse-distance relationships is given in Figure 2.3, taken from the same
reference. He proposed that the factor in Eq. (1.25) should be 0.054. He also
proposed factors of 0.036 for heavily cased charges and 0.081 for bare charges.
Data from ground bursts of hemispherical TNT charges between 5 and 500
tons in weight, and of nuclear charges ranging from 20 tons to 1.8 kilotons
were later analysed by Kingery [2.1], and have been reported in detail by
Baker [4.4]. Experimental results obtained at Suffield, Canada, in the 1960s
on TNT hemispherical ground-burst charges in the 500 ton range have been
Figure 2.2 Relationship between incident pressure and scaled distance for Second
World War bombs and bare charges (from Kennedy, ref. 1.11).