Measurement of Composition B Detonation Performance above the TNT Melting Point*

Composition B (Comp B) is an explosive composed of RDX and TNT, typically in a 60/40 wt. % ratio. When heated above the TNT melting point, the suspended RDX crystals can settle, resulting in a composition gradient. While it is possible to measure the detonation performance of such a material, the resulting data is difficult to apply to computer models since the composition at any given location is not known experimentally. To ensure a uniform composition at these temperatures, we have designed an experimental apparatus to rotate the explosive during heating. Details of the apparatus are described and experimental results are reported which demonstrate its effectiveness. In particular, measured cylinder expansion test wall velocity profiles, front shapes, and steady detonation velocities are compared for nominally identical experiments with the exception of whether rotation was used during heating. Results show that the detonation front-shape is especially sensitive to the effect of rotation, suggesting that RDX particle settling is significant at 120 °C.