Shock initiation of the TATB-based explosive PBX 9502 heated to 130°C

Ultra‐small‐ and small‐angle neutron scattering techniques were employed to quantify thermally driven changes to the microstructure of the TATB‐based composite high explosive, PBX 9502. Samples of PBX 9502 were studied in‐situ at temperatures ranging from 25 to 220 °C and after re‐equilibration at ambient temperature. Significant changes to the void size and morphology within the PBX 9502 microstructure were observed upon heating and are consistent with the known increase in the shock sensitivity of thermally‐treated PBX 9502. More extensive microstructural changes were found after the thermally treated samples were re‐equilibrated at ambient temperature. Utilizing a model of ramified porosity, the size and the volume and surface dimensions of voids in the PBX 9502 microstructure were quantified as a function of temperature. The temperature dependence of the void radius of gyration is well correlated with the known increase in the shock sensitivity of PBX 9502 with increasing temperature, providing a microstructural origin for the increased shock sensitivity of PBX 9502 at elevated temperatures.

Section: Introductionmentioning

confidence: 99%

Thermally‐Driven Changes to Porosity in TATB‐Based High Explosives

Armstrong

Mang

2021

“…The parameter G 1 (T) is fitted as a function of temperature T for the RDX-based aluminized explosive [23]:…”

Section: Simulated Jet Initiation Of Covered and Heated Explosivementioning

confidence: 99%

“…where P E and P p are the initial and product pressures, respectively; V E and V p are the initial specific volume and product specific volume of the explosives, respectively; C v is the heat capacity; T 0 is the initial temperature of the explosive; T p is the product temperature; and A, B, R 1 , R 2 , and ω are constants. The jet-initiating covered explosive was simulated using literature values [23] for the ignition-and-growth model parameters of the RDX-based aluminized explosive. The accuracy of the simulation results was verified by comparing them with the experimental results.…”

Section: Simulated Jet Initiation Of Covered and Heated Explosivementioning

confidence: 99%

“…Garcia et al [20] found that increasing the volume of 2,6-diamino-3,5-dinitropyrazine-1-oxide (LLM-105) improved the explosive shock sensitivity. The particle velocity inside explosives was measured at different temperatures by Gustavsen et al [21][22][23], who found that the detonation distance decreased with increasing temperature. Chen et al [24] conducted experiments using explosive-driven, flyer-initiating, heated hexanitrohexaazaisowurtzitane (CL-20).…”

Section: Introductionmentioning

confidence: 99%

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Shaped‐Charge Jet‐Initiation of Covered RDX‐Based Aluminized Explosives and Effect of Temperature

Chen

Yang

et al. 2020

Understanding the shaped‐charge jet‐initiation mechanism of covered explosives and the effect of explosive temperature is important for ammunition safety. We devised a method of using a shaped‐charge jet‐penetrating cover to shock‐initiate heated explosives. This method achieves uniform temperature control of explosives via heating the upper and lower ends and preserves heat on the side of the explosive charge. We experimentally tested the method on hexahydro‐1,3,5‐trinitro‐1,3,5‐triazine (RDX)‐based aluminized explosives (61 wt.% RDX, 30 wt.% Al, 9 wt.% binder) at different temperatures and cover thicknesses. The jet‐penetration behavior and explosive detonation‐wave growth were observed via X‐ray photography, and the effect of explosive temperature on jet initiation was analyzed. A numerical model of the shaped‐charge jet‐initiating explosive was set up by considering the temperature change of the explosive and analyzing the detonation‐wave growth and initiation thresholds of different explosive temperatures under jet shock initiation. Under a thin cover, the explosive showed prompt impact initiation by the jet; the initiation occurred very near to the explosive surface. However, for a thick cover, the explosion was initiated by a bow wave formed at a certain distance from the upper surface of the explosive, and a retonation wave was observed. The temperature of RDX‐based aluminized explosives affects the two jet‐initiation mechanisms. The shock sensitivity of the explosives to the jet decreased with increasing temperature, but the shock sensitivity increased when the temperature exceeded a certain value. A simulation method was established that can be used to predict shaped‐charge jet initiation at different explosive temperatures. We obtained the relationship between the cover thickness and run‐to‐detonation distance under jet shock initiation, which provides a theoretical basis for safety analysis and evaluation of a warhead charge that is attacked by a shaped‐charge jet.

“…Garcia et al [4] applied initiation tests to RX-55-AA (95 wt % LLM-105, 5 wt % Viton) explosives at 25°C and 150°C and found that the volume expansion of LLM-105 that was caused by the increase of explosives temperature increased the shock sensitivity of the explosives. Gustavsen [5][6][7] completed shock-initiation experiments on PBX-9502 (95 wt % TATB, 5 wt % Kel-F800) by using a gas-gun driven non-magnetic stainless-steel flyer, by measuring the particle velocity inside the explosives at different temperatures and investigated the influence of temperature on shock sensitivity. Chen Lang et al [8][9] proposed a test method for explosive-driven flyer-initiating explosives and achieved uniform explosive heating.…”

Section: Introductionmentioning

confidence: 99%

Effect of Temperature on Shock Initiation of RDX‐Based Aluminized Explosives

Chen

Yang

et al. 2019

An increase in temperature of an explosive will lead shock sensitivity to change, which affects explosive safety. Therefore, a study of the effect of temperature on the shock initiation of explosives is of great significance. We carried out a series of tests on explosive-driven flyer-initiating heated RDX-based aluminized explosives (61 wt % RDX, 30 wt % Al, 9 wt % binder) and the temperature and input shock pressure of the explosives were controlled accurately during the tests. The pressure histories at different depths inside the explosives were measured by using manganin pressure gauges, and the effect of temperature on detonation wave growth was analysed. The ignition and growth reaction model, some parameters of which rely on temperature, was used to simulate the shock-initiation processes.The relationship between the model parameters and the temperature were obtained from the experimental results. The run distance to detonation as a function of the initial input pressure in a temperature range, the Pop plot, and the reaction degree of the explosives were determined. For the RDX-based aluminized explosives, binder softening and the increasing sensitivity of RDX are the two main reasons that change the shock sensitivity. For 25°C-110°C, the shock sensitivity decreases with an increase in temperature, mainly because of binder softening. However, for 110°C-170°C, the shock sensitivity increases with an increase in temperature, which depends on the increasing sensitivity of the RDX. Figure 5. Calculated and measured pressure histories of different temperatures at different depths with 10-mm thick PTFE separator. (a) 42 � C, (b) 100°C, (c) 170°C. Effect of Temperature on Shock Initiation of RDX-Based Aluminized Explosives Propellants Explos. Pyrotech. 2019,