Studies on Physico-Mechanical and Explosive Characteristics of RDX/HMX-Based Castable Plastic-Bonded Explosives

Gharia, J. S.; Sinha, Rabindra Kumar; Trads, V. V.; Prakash, Vinay; Phadke, V.K.

doi:10.14429/dsj.48.3877

Cited by 10 publications

(5 citation statements)

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“…It shows that the fluoropolymers agglomerate in a network structure in which the agglomerations are linked by several fluoropolymer chains, and TATBs are buried in such networks. In other words, the fluoropolymers form a polymeric matrix holding the solid TATB explosive particles together, which is in good agreement with experimental observations [22]. It also explains the poor wrap property of the fluoropolymers in the TATB-based PBX.…”

Section: Aggregate Behaviour Of Fluoropolymerssupporting

confidence: 88%

Mesoscopic simulation of aggregate behaviour of fluoropolymers in the TATB-based PBX

Ji¹,

Zhao²,

Gong

et al. 2011

Molecular Simulation

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The aggregate behaviours of fluoropolymers F 2311 , F 2312 , F 2313 and F 2314 in TATB-based PBX were studied using the dissipative particle dynamics method. All of these four different fluoropolymers form the mesh-ball-like structure, in which the triaminotrinitrobenzene (TATB) explosive is wrapped. The self-aggregate behaviour and the poor wrap property of fluoropolymers in the TATB-based PBX are consistent with the experimental observation. Simulations with various chlorotrifluoroethylene (CTFE) contents were made. Results indicate that some fluoropolymers are disengaged from the main spherical phases forming a new small spherical phase with the increasing of CTFE content in fluoropolymers. The fluoropolymers form mesh and honeycomb structures at 350 and 400 K, respectively. In addition, the dynamic behaviour of fluoropolymers in TATB-based PBX was also studied and analysed in detail.

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Section: Aggregate Behaviour Of Fluoropolymerssupporting

confidence: 88%

Mesoscopic simulation of aggregate behaviour of fluoropolymers in the TATB-based PBX

Ji¹,

Zhao²,

Gong

et al. 2011

Molecular Simulation

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“…We chose the mass ratio of binder over DOA to be 1.03, which leads to the optimum viscosity and compression strength. 21 Each chain contains ten HTPB repeat units connected via one IPDI crosslinking molecule to four terminal HTPB repeat units per end. The initial conformation was based on rotational isomeric states (RISs) statistics to determine the dihedral angle values for each chain and its repeating units.…”

mentioning

confidence: 99%

Elucidation of the dynamics for hot-spot initiation at nonuniform interfaces of highly shocked materials

Zybin

Goddard

et al. 2011

Phys. Rev. B

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The fundamental processes in shock-induced instabilities of materials remain obscure, particularly for detonation of energetic materials. We simulated these processes at the atomic scale on a realistic model of a polymer-bonded explosive (3,695,375 atoms/cell) and observed that a hot spot forms at the nonuniform interface, arising from shear relaxation that results in shear along the interface that leads to a large temperature increase that persists long after the shock front has passed the interface. For energetic materials this temperature increase is coupled to chemical reactions that lead to detonation. We show that decreasing the density of the binder eliminates the hot spot. The interaction of shock waves with nonuniform interfaces plays an essential role in the interfacial instabilities in inertial confinement fusion (ICF), in shock-induced RichtmyerMeshkov instabilities (RMIs), and in detonation in heterogeneous polymer-bonded explosives (PBXs). For detonation, it is generally accepted that hot spots form during the development of instabilities as shock waves pass through the interface or other defects.1-4 Despite numerous experimental and theoretical studies, the fundamental processes involved remain controversial. This is due to the complex environment and coupling of thermal, chemical, and mechanical degree of freedom, which is extremely difficult to unravel experimentally. It has also been very difficult theoretically to include the reactive processes involved and yet cover the enormous size and time scales intrinsic to the phenomena.To discover the origin of shock-induced hot-spot formation, we carried out reactive dynamics (RD) using the ReaxFF reactive force field on a realistic model of a real polymerbonded explosive PBX N-106. Energetic materials (EMs) are essential for applications ranging from rocket engines, to building and dam construction, and to armaments. Generally the EM is bound together in a matrix of polymer elastomers to form the PBX that can be molded into various shapes, while providing some control in resisting unintentional detonation due to shocks or friction. Unfortunately, current generations of PBXs are sensitive to accidental detonation, despite many attempts to control the safety by improvements in materials and manufacturing practices. Here we use the ReaxFF reactive force field to examine the effect of shocks on realistic models of polymer-bonded explosives, where we use these simulations to extract the mechanism of hot-spot formation. Then, based on this model, we predict how to change the system to reduce the hot spot, and carry out simulations to validate this prediction.ReaxFF has now been established to provide nearly the accuracy of quantum calculation in the various reaction barriers and rates while providing a computational efficiency nearly that of ordinary molecular dynamics (MD) with ordinary force fields (FFs), enabling us to study the complex processes involved in interfacial instabilities at the atomic scale, providing insights on such phenomenon. Thus ReaxF...

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“…Finally, the samples were cured at the ambient temperature for 48 h. To achieve a high solid loading of RDX/HMX in HTPB-based PBXs, attention was paid to particle size distribution of the explosive component. Solid loading was optimized using bi-modal and tri-modal mixtures of the explosive [42]. Aluminum powder, typically ~50 µm average diameter, was also applied.…”

Section: Methodsmentioning

confidence: 99%

Quantitative analysis for the determination of aluminum percentage and detonation performance of aluminized plastic bonded explosives by laser-induced breakdown spectroscopy

et al. 2018

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The aluminized plastic-bonded explosive (PBX) is a composite material in which solid explosive particles are dispersed in a polymer matrix, which includes three major components, i.e. polymeric binder, metal fuel (aluminum) and nitramine explosive. This work introduces a new method on the basis of the laser-induced breakdown spectroscopy (LIBS) technique in air and argon atmospheres to investigate the determination of aluminum content and detonation performance of aluminized PBXs. Plasma emissions of aluminized PBXs are recorded where atomic lines of Al, C and H as well as molecular bands of AlO and CN are identified. The experimental results demonstrate that a good discrimination and separation between the aluminized PBXs is possible using LIBS and principle component analysis, although they have similar atomic composition. Relative intensity of the AlO/Al is used to determine aluminum percentage of the aluminized PBXs. The obtained quantitative calibration curve using the relative intensity of the AlO/Al is better than the resulting calibration curve using only the intensity of Al. By using the LIBS method and the measured intensity ratio of CN/C, an Al content of 15% is found to be the optimum value in terms of velocity of detonation of the RDX/Al/HTPB standard samples.

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Studies on Physico-Mechanical and Explosive Characteristics of RDX/HMX-Based Castable Plastic-Bonded Explosives

Cited by 10 publications

References 0 publications

Mesoscopic simulation of aggregate behaviour of fluoropolymers in the TATB-based PBX

Mesoscopic simulation of aggregate behaviour of fluoropolymers in the TATB-based PBX

Elucidation of the dynamics for hot-spot initiation at nonuniform interfaces of highly shocked materials

Quantitative analysis for the determination of aluminum percentage and detonation performance of aluminized plastic bonded explosives by laser-induced breakdown spectroscopy

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