Gurney velocity modification for detonation-driven steel cylindrical casings

Detonation-driven experiments for 2,4,6-trinitrotoluene in standard copper cylindrical casings and in 50SiMnVB and 45 steel cylindrical casings with three thicknesses were carried out in this study. The results showed that due to the influences of the coupled loading of the shock waves and the detonation products, the initial velocity of the fragments of the steel cylinders predicted using the Gurney formula and Gurney velocity obtained from a standard cylinder experiment significantly deviated from the experimental observations. This was caused by the difference in the cylinder density and the load coefficient β. Thus, a modified method and model of the Gurney velocity were proposed, and modification coefficients were obtained via a numerical simulation, which provided a means for a more accurate calculation of the initial velocity of fragments of the steel cylinder. Moreover, further analysis showed that at the same β value, the modified Gurney velocity of the copper cylinder was larger than that of the steel cylinder. The modified Gurney velocity of the same cylinders increased with the increase in the β value. The smaller the β value was, the larger the increase in the ratio was. When β > 0.8, the modified Gurney velocity became constant.