A Study On Shock Initiation Of Wedge-shaped Explosives With Laser Interferometry

Shock initialization of explosives which is especially significant to the study of essential mechanism of initialization draws a plentiful attention of investigators in the detonation domain.Shock initialization of explosives pay a lot of attention on the developing course of shock waves in the explosives when it is initiated by different pressure. Velocity of shock waves, velocity of particle and pressure after shock waves all can be taken to represent the development process of the shock waves in the explosives, but it is still very difficult to obtain a unabridged or high precision date by the current measurement.In this paper,we shall build an new experimental method which can gather unabridged and higher precision date of particle velocity in order to study the shock initialization of explosives. We also apply the experimental method into the shock initialization study of a new IHE(insensitive high explosives) named JBO-9021. This paper is comprised of three parts:1) A new experimental method was built to study the shock initialization of explosives which combined the laser interferometry and wedge-shaped explosives. Particle velocity history was achieved by the new method is also compared with date taken by two other traditional experimental methods. Results shows that the error is about 2% and 5% at the shock and detonation phase which proves that the method built in this paper is feasible to sudy the shock initialization of explosives.2) The shock initialization performance of a new TATB-based insensitive high explosives-JBO-9021 is studied with the experimental method built in this paper and particle velocity history at different positions were obtained. The parameters of hugoniot of unreacted JBO-9021 explosives and Pop relationship were derived from analytical analysis and non-linear curve fit at pressure between 10.3Gpa to 27.1Gpa. The hugoniot relationship can be expressed as Df=1.07+3.18Up, and the Pop relationship can be expressed as log(X)=(2.951±0.182)-(2.246±0.152)log(P).3) A reduction model was used in the date analysis which may contribute error to result. In the actual process, the shap of shock waves travels into the LiF window will change for the different shock impedances between test explosives and LiF window. Numerical simulation shows that the error bring by the reduction model is only 3% which can be nearly ignored.