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Science and Technology of Energetic Materials

Vol.70, No.4 (2009)

Research paper

Fragment velocity measurement of steel container during explosion tests by using high-speed and flash X-ray photography
Kunihiko Wakabayashi, Tomotaka Homae, Koki Ishikawa, Eishi Kuroda,
Tomoharu Matsumura, and Yoshio Nakayama
p.94-100

Abstract

Explosion tests were performed using a steel container filled with explosive to determine fundamental properties such as flight velocity, direction, and distribution of fragments. A cylindrical steel container filled with trinitrotoluene (TNT) was prepared as a test sample representing a one-ton bomb. The length to inner diameter ratio (L/I.D.) of the container was set to about two. Images of flying fragments were recorded by a high-speed camera in field explosion tests, and by two flash X-ray tubes and film in indoor explosion tests. In the case where the direction from the center of the container to its open end was defined to be an azimuthal angle of zero degrees, many fragments were distributed at azimuthal angles of around 100 degrees. In an explosion using a container with 1 kg of TNT, the highest fragment velocity determined by the time-of-flight method was 1700 ± 50 m•s-1 at a distance of 11.56 ± 0.01 m from the explosion point. However, the initial fragment velocity determined by flash X-ray photography was 2194 m•s-1. Thus, the fragment velocities determined by different photographic techniques did not agree. This discrepancy between the observed fragment velocities could be explained by assuming that the fragment velocity depends solely on air resistance.

Keywords

steel container, fragment velocity, high-speed photography, flash X-ray photography,
air resistance

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