ACOUSTICAL PROPERTIES OF END-INITIATED EXPLOSIVE LINE CHARGES

Acoustic radiation produced by end-fired explosive line charges is exa mined experimentally and theoretically. Three explosive compositions a re studied: PETN detonating cord, RDX detonating cord, and thin ribbon s of HLX. Specific output levels are formulated for each of the three explosive materials over the four 1-oct bands spanning 50-800 Hz. Bubb le period relationships are derived for each material and compared to previous studies. In terms of directivity effects, long line charges a re found to behave like beam-steered continuous arrays over moderately wide bands. A math model is developed which predicts acoustic levels and spectrum shapes for the shock wave component over a wide range of view angles and linear charge densities. This model is driven by two p arameters which are extracted from the experimental data for the three compositions studied. The result is a practical means of designing ex plosive line arrays to desired source levels, bandwidths, and beam pat terns. (C) 1998 Acoustical Society of America.