A novel method for prediction of the critical diameter of solid pure and composite high explosives to assess their explosion safety in an industrial setting

ABSTRACT

For the explosion safety assessment in an industrial setting, the knowledge of critical diameter of high explosives provides important information on the sensitivity and conditions whereby detonations are likely to occur. The critical diameter or failure diameter is the minimum diameter of a cylindrical charge of high explosive which sustains a high order steady-state detonation. Available predictive methods require complex models, which are based on complicated variables such as the shock adiabat, and the generalized kinetic characteristic of decomposition of a high-explosive charge under shock-wave compression. For the first time, this paper describes a novel simple method for assessment of the critical diameter of pure and composite CHNO high explosives. The new model is based on the contribution of the number of nitrogen and oxygen atoms as well as some conditions, which are based on shock sensitivity, impact sensitivity and the negative values for core critical diameter of the desired explosives under certain situations. Experimental data of 42 high explosives have been used to derive and test the new model. The predicted critical diameters for building the model (29 explosives) and the test set (13 explosives), under the unconfined condition of these explosives, have the values of root-mean-square deviation (RMSD) of 5.14 and 3.96 mm, respectively.