EFFECTS OF TANDEM AND COLLIDING SHOCK-WAVES ON THE INITIATION OF TRIAMINOTRINITROBENZENE

The shock initiation of the insensitive high-explosive LX-17, which co ntains 92.5% triaminotrinitrobenzene and 7.5% Kel-F binder, was studie d under simulated accident conditions in which two shock waves interac t producing locally high pressures and temperatures. Two experimental geometries were studied using embedded manganin pressure gauges to mea sure the increases in pressure due to exothermic reaction at various l ocations as functions of time. These pressure histories were compared to ignition and growth reactive flow model calculations to determine w hether a second shock compression of reacting LX-17 caused unusually r apid reaction rates and thus more extreme hazards. One experiment used a tandem flyer plate of aluminum and steel separated by a gap to shoc k. the LX-17 charge, allow it to rarify, and then reshock the damaged charge to even higher pressures. These experiments revealed no signifi cant enhancement of the LX-17 reaction rates under this shock, rarefac tion, and reshock loading. The second experiment used a grooved flyer plate to produce a subcritical shock wave in LX-17, which then diverge d and collided, producing a Mach stem interaction at the charge axis. The threshold conditions under which the Mach stem grew to detonation were measured. The standard LX-17 ignition and growth model yielded ex cellent agreement with the pressure gauge records in the Mach stem int eraction region. The formation of Mach stem interactions by nearly sim ultaneous multiple high-velocity impacts was identified as a serious s hock initiation hazard for heterogeneous solid explosives.