X‐ray Phase Contrast Imaging of the Impact of Multiple HMX Particles in a Polymeric Matrix

Kerschen, Nicholas E.; Drake, Jonathan D.; Sorensen, Christian J.; Guo, Zherui; Mares, Jesus O.; Fezzaa, Kamel; Sun, Tao; Son, Steven F.; Chen, Weinong W.

doi:10.1002/prep.201900217

Cited by 9 publications

(3 citation statements)

References 24 publications

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“…Purdue maintains a 38.1 mm bore, single-stage, helium-powered, light gas gun there. The gun and experimental diagnostics details can be found in previous papers based on our work [13][14][15]. The upper velocity of the gun is limited because of the space requirements of sector 32B and tops out near 550 m/s.…”

Section: Experimental Configurationmentioning

confidence: 99%

Phase Contrast X‐Ray Imaging of the Collapse of an Engineered Void in Single‐Crystal HMX

Blum‐Sorensen

Duarte

Drake

et al. 2022

Propellants Explo Pyrotec

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Imaging the collapse of a single void that creates a hot spot initiation site in an otherwise defect‐free explosive is challenging given the spatial and temporal scales involved in explosive systems. This work presents our attempt to examine a single hot spot mode (void collapse) in single‐crystal octahydro‐l,3,5,7‐tetranitro‐l,3,5,7‐tetrazocine (HMX) embedded in Sylgard. The hot spot heating mechanisms involved with pore collapse include adiabatic heating, jetting, and viscoplastic dissipation. Quantifying the dynamics of a pore collapse is a crucial step to understanding which mechanisms dominate during ignition events. Our experiments were conducted with a single‐stage, light‐gas gun at Argonne National Laboratory's Advanced Photon Source, applying the phase contrast imaging technique while collecting high‐speed video. The details of HMX single crystal production, defect (pore) engineering, and sample construction, along with experimental results are presented here. These results demonstrate that detailed collapse dynamics can be obtained from homogeneous, single‐crystal explosives with this approach. Qualitative comparisons are made with simulation data which show good agreement in the transition between a quasi‐symmetric pore collapse and an asymmetric collapse with jetting across the pore as measured with normalized pore area and pore circularity.

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Section: Experimental Configurationmentioning

confidence: 99%

Phase Contrast X‐Ray Imaging of the Collapse of an Engineered Void in Single‐Crystal HMX

Blum‐Sorensen

Duarte

Drake

et al. 2022

Propellants Explo Pyrotec

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“…However, these studies are mainly based on surface observation and fracture surface analysis of the specimens, which cannot reveal the internal damage behavior of PBXs during loading [9]. With the development of ray detection technology, X-rays have been widely used in the study of the mechanical properties of explosives and their crystal particles [11][12][13]. Researchers also applied X-ray computed tomography (CT) technology to study the internal structure characteristics and defects of PBXs.…”

Section: Introductionmentioning

confidence: 99%

Experimental Study on the Localized Deformation and Damage Behavior of Polymer-Bonded Explosive Simulant under Cyclic Compression

Jia,

Hao,

Peng

et al. 2024

Materials

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Uniaxial cyclic compression tests were performed to investigate the compression deformation and damage of polymer-bonded explosive (PBX) simulant, particularly shear localization. The macroscopic mechanical behavior and mesoscale failure mechanisms of the PBX simulant were analyzed by optical observation and SEM scanning methods. After each cyclic compression, the specimen was scanned by X-ray computed tomography (CT), and the internal 3D deformation of the specimen was calculated using the digital volume correlation (DVC) method. The results show that the stress–strain curve of the PBX simulant exhibits five stages and coincides with the morphological changes on the surface of the specimen. The mesoscale failure mechanism is dominated by particle interface debonding and binder tearing, accompanied by a small amount of particle breakage. There are three bifurcation points (T1, T2, and T3) in the curves of the normal and shear strain components with compression strain. It was found that these bifurcation points can reflect the full progression of the specimen from inconspicuous damage to uniformly distributed damage, shear localization, and eventual macroscopic fracture. The strain invariant I1 can quantitatively and completely characterize the deformation and damage processes of the PBX simulant under cyclic compression.

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“…The role of friction is also addressed by a third approach based on a damage phase field to describe the appearance and evolution of cracks [13,15,16,27,28]. This method allows (1) to replicate the damage observed during impacts on single crystals [18,28] and (2) to reproduce the initiation threshold of the β-HMX single crystal observed at 445 m/s [16,29]. The binder/β-HMX interface behavior is favorable to the appearance of critical hot spots under an impact of 400 m/s [16,27].…”

Section: Introductionmentioning

confidence: 99%

Plastic Dissipation and Hot‐Spot Formation in HMX‐Based PBXs Subjected to Low Velocity Impact

Drouet

Picart

Bailly

et al. 2020

Propellants Explo Pyrotec

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Low-velocity, shock-free impact is one of the accidental loads that can lead to a thermal explosion, the latter being the consequence of a chain of mechanisms depending on the microstructure of the material. To investigate the causes, the predictive capability of numerical tools depends on the physics embedded in the models. While a consensus has developed around the concept of hot spots, the exact nature of the thermo-mechanical heat-generating processes that preceded them remains to be clarified. We are studying a composition similar to the PBX 9501. HMX crystals are mixed with a few percent of a polymer binder. Recent experiments (reverse edge-on impact test) have revealed the influence of the plasticity of HMX grains even at low strain rates and low confinement. The heat released by the plastic dissipation has been identified as a potential candidate for the formation of hot spots. In this study, a numerical representation based on a polycrystalline β-HMX material subjected to intense shear is presented. Due to the high pressure generated by the impact, the intergranular slip is ignored. Emphasis is placed on the heterogeneity resulting from the micro-structural characteristics and the interaction between the anisotropic single crystals. The behavior of the binder and the influence of other heterogeneities such as friction or micro cracks are set aside. Finally, the mechanical dissipation is calculated in the models and the maximum temperature is deduced.

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X‐ray Phase Contrast Imaging of the Impact of Multiple HMX Particles in a Polymeric Matrix

Cited by 9 publications

References 24 publications

Phase Contrast X‐Ray Imaging of the Collapse of an Engineered Void in Single‐Crystal HMX

Phase Contrast X‐Ray Imaging of the Collapse of an Engineered Void in Single‐Crystal HMX

Experimental Study on the Localized Deformation and Damage Behavior of Polymer-Bonded Explosive Simulant under Cyclic Compression

Plastic Dissipation and Hot‐Spot Formation in HMX‐Based PBXs Subjected to Low Velocity Impact

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