Study on Overdriven Detonation of Double‐Layer Shaped Charge

Abstract

AbstractOverdriven detonation(ODD) means that the detonation process of explosives no longer follows the C−J detonation process and its detonation parameters are larger than the C−J values. ODD is an unstable detonation process. With the increasing of propagation distance, detonation parameters tend to C−J value gradually. The double‐layer shaped charge (DLSC) with high detonation velocity explosive (HE) in the outer layer and low detonation velocity explosive (LE) in the inner layer can keep the axis of shaped charge in the ODD state all the time. The paper derived formulas for calculating the parameters of overdriven detonation when the HE detonates the LE. Based on the conservation of momentum, mass and energy, the functional relationship between the intensity of Mach wave and the incident angle of the detonation wave in the shaped charge is deduced. Study on the propagation law of detonation waves in DLSC with the wave shaper by numerical simulation. The results show that the peak value of Mach wave pressure in DLSC is not increased compared with that in ordinary shaped charge (OSC), but the attenuation speed of Mach wave pressure can be delayed and ultimately in the ODD state. The final parameters of the ODD state are determined by the detonation velocity and the polytropic exponent of the explosive. The results of numerical simulation are consistent with theoretical calculation, which confirms the accuracy of the formulas.