Measurement of the shock profiles with streak technique and different detonating arrangements

Abstract

The complex pressure profiles or better the shocked volume of shock waves induced in specimens by detonating high explosive arrangements can be measured with a single test if the shock velocities are observed in a large plexiglas-block with both high time and especially also high space resolution. A " large" plexiglass block is necessary that the rarefaction wave from the surfaces is not able to influence the shock profile from the source. The time resolution is generally no problem if an adequate rotating mirror camera is used. High space resolution can also be obtained if a fine grid is used - in this case of 0. 1 mm strips spaced 0. 4 mm apart and glued in the center plan of the plexiglass block. This technique shows that the shock profile for a high explosive charge without any cover plate gives the highest peak pressure which decays quickly. The detonating high explosive charge which is covered with a two millimeter thick disc of copper shows a shock profile which is constant over a certain time. An airgap between the high explosive charge and the measuring plexiglass block always gives a weak shockwave in the beginning. In the case of an uncovered high explosive charge the expansion of the high explosive products gives a fairly smoothly increasing blast or shock wave and in the case of a covered high explosive charge a