A CREST model for the RDX/TNT explosive Composition B

Abstract

The high explosive Composition B (Comp B), which comprises approximately 60% RDX and 40% TNT by weight, is still widely used for a range of applications, and reactive burn models able to simulate its shock initiation and detonation response are required for modelling assessments. CREST is unique among such models in using an entropy-dependent reaction rate to convert the solid unreacted explosive to gaseous detonation products. This paper describes the calibration of a CREST reactive burn model for Comp B. The equations of state are fitted to available shock Hugoniot, sound speed and overdriven detonation wave data, and are demonstrated to be suitably robust and compatible. The reaction rate has been tuned to fit recent sustained-shock-gas-gun data and, owing to a lack of modern data, a detonation size-effect curve dating from the 1950's on a slightly different Comp B variant. This made it necessary to accept a compromise fit to the calibration data, and which is explored further in the paper. The model is then tested against other Comp B data from the literature to assess its ability to predict a wide range of behaviour. CREST now adds to those reactive burn models available for simulating this well-studied explosive.