Microstructural level response of HMX–Estane polymer-bonded explosive under effects of transient stress waves

Barua, Ananda; Horie, Y.; Zhou, Min

doi:10.1098/rspa.2012.0279

Cited by 43 publications

(23 citation statements)

References 22 publications

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“…This indicates the possibility of force chains in the material, and there might be some crystals that form favorable paths for the load transfer mechanism. The speculated force chains are based on the continuity of the compressive strain across the specimen length, and are in crystals either in contact or very close to each other, which agrees well with the fact that as the solid loading increases it results in permanent stress bridging [28]. However considering the percentage of solid loading used in the specimen, additional work is needed at different solid loadings to reach a conclusive observation on the force chain formation in the material.…”

Section: Mesoscale Deformation Behaviorsupporting

confidence: 71%

Local Deformation and Failure Mechanisms of Polymer Bonded Energetic Materials Subjected to High Strain Rate Loading

Ravindran

Tessema

Kidane

2016

J. dynamic behavior mater.

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The dynamic multi-scale deformation mechanism of polymer bonded energetic material is investigated. Samples made of polymer bonded sugar (a known simulate for polymer bonded explosives) with 85 % sugar crystals and 15 % polymer binder are used. The samples are dynamically compressed using a split Hopkinson pressure bar. Using a high magnification, meso-scale 2D digital image correlation experimental setup, the local deformation is measured in situ at sub-grain scale. The macroscale deformation mechanism is also investigated with the help of 3D digital image correlation. From the mesoscale experiment, it is observed that the local strain distribution in the specimen is highly heterogeneous with large strain localization occurring at the polymer rich areas between the crystal boundaries. Deformations of the majority of the crystals are minimal, and usually realign themselves to accommodate large deformation of the binder by rigid rotation and sliding. Due to this, delamination of the polymer binder from crystals and binder cracking are the main local failure modes. It is also observed that the presence of small crushed crystals from material processing are the favorable sites for this opening mode failure.

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Section: Mesoscale Deformation Behaviorsupporting

confidence: 71%

Local Deformation and Failure Mechanisms of Polymer Bonded Energetic Materials Subjected to High Strain Rate Loading

Ravindran

Tessema

Kidane

2016

J. dynamic behavior mater.

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“…(4.1) in Ref. 46. For a grain volume fraction of 0.95, such as that used in PBX9501, the average stress is predicted to be $457 MPa, which is within 3.3% of the value obtained from experiments.…”

Section: Large Samples Without Wave Reflectionsmentioning

confidence: 52%

“…In Ref. 46, the authors quantified the evolution of fracture energy. An analysis of the spatial distribution of fracture energy showed that the maximum fracture dissipation occurs near the impact face and gradually decreases to zero at the front of the stress wave.…”

Section: Large Samples Without Wave Reflectionsmentioning

confidence: 99%

Ignition criterion for heterogeneous energetic materials based on hotspot size-temperature threshold

Barua

Kim

Horie

et al. 2013

Journal of Applied Physics

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A criterion for the ignition of granular explosives (GXs) and polymer-bonded explosives (PBXs) under shock and non-shock loading is developed. The formulation is based on integration of a quantification of the distributions of the sizes and locations of hotspots in loading events using a cohesive finite element method (CFEM) developed recently and the characterization by Tarver et al. [C. M. Tarver et al., "Critical conditions for impact-and shock-induced hot spots in solid explosives," J. Phys. Chem. 100, 5794-5799 (1996)] of the critical size-temperature threshold of hotspots required for chemical ignition of solid explosives. The criterion, along with the CFEM capability to quantify the thermal-mechanical behavior of GXs and PBXs, allows the critical impact velocity for ignition, time to ignition, and critical input energy at ignition to be determined as functions of material composition, microstructure, and loading conditions. The applicability of the relation between the critical input energy (E) and impact velocity of James [H. R. James, "An extension to the critical energy criterion used to predict shock initiation thresholds," Propellants, Explos., Pyrotech. 21, 8-13 (1996)] for shock loading is examined, leading to a modified interpretation, which is sensitive to microstructure and loading condition. As an application, numerical studies are undertaken to evaluate the ignition threshold of granular high melting point eXplosive, octahydro-1,3,5,7-tetranitro-1,2,3,5-tetrazocine (HMX) and HMX/Estane PBX under loading with impact velocities up to 350 ms À1 and strain rates up to 10 5 s À1. Results show that, for the GX, the time to criticality (t c) is strongly influenced by initial porosity, but is insensitive to grain size. Analyses also lead to a quantification of the differences between the responses of the GXs and PBXs in terms of critical impact velocity for ignition, time to ignition, and critical input energy at ignition. Since the framework permits explicit tracking of the influences of microstructure, loading, and mechanical constraints, the calculations also show the effects of stress wave reflection and confinement condition on the ignition behaviors of GXs and PBXs.

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“…Reaugh et al [10] developed a high explosive response to the mechanical stimulus model (HERMES) by simultaneously considering the yield strength, the equation of state, particle fractures, and so on, and also built up the relationship between cracks and ignition. However, because these models could not describe the microstructural effect of PBXs, Barua and Zhou [11] and Barua et al [12][13] developed a Lagrangian framework based on the cohesive finite-element method to analyze the crack evolution of the interface between the explosive crystal and polymer and further the ignition induced by the shock wave generated from the high-velocity impact, in view of the PBX microstructure. Although these works revealed that the hot-spot formation was initiated by microcracks, how the stochasticity of the microcracks affected hot-spot formation was not quantified in detail.…”

Section: Introductionmentioning

confidence: 99%

Non‐Shock Ignition Probability of Octahydro‐1,3,5,7‐Tetranitro‐Tetrazocine‐Based Polymer Bonded Explosives Based on Microcrack Stochastic Distribution

Chen

Zhang

et al. 2019

Propellants Explo Pyrotec

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We investigate stochastic microcracks of a heterogeneous microstructure as the primary mechanism determining the non‐shock ignition probability of octahydro‐1,3,5,7‐tetranitro‐1,2,3,5‐tetrazocine‐based polymer‐bonded explosives. To quantify the ignition probability, we modify the viscoelastic cracking constitutive model by considering randomly distributed microcracks and combine this model with the hot‐spot model and the Monte Carlo method. This method is validated by using a standard Steven test simulation, and we quantify how the microcrack stochasticity affects the ignition probability. The high‐temperature region clearly changes compared with the case of single microcrack size. The discrepancy in the mechanical response of each element due to the heterogeneous microcracks causes a shear deformation, which increases the temperature. The difference between a uniform distribution and a normal distribution in microcrack size is also discussed. For a given impact velocity, the ignition probability for the normal microcrack size distribution exceeds that for the uniform microcrack size distribution. Although the two distributions have the same mean and variance, the real range in microcrack size corresponding to the normal distribution exceeds that for the uniform distribution. The results show that the sample radius does not significantly affect the ignition probability, whereas the opposite is true for the sample thickness. The ignition‐probability curve is obtained in these cases. For sample dimensions of φ70 mm×13 mm, φ98 mm×13 mm, φ140 mm×13 mm, and φ98 mm×26 mm, the impact velocity thresholds corresponding to ignition probabilities in the range 0 %–99 % are 41.0–43.7, 41.0–44.3, 40.0–44.6, and 62.0–67.2 m/s, respectively, which is consistent with experimental results.

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Microstructural level response of HMX–Estane polymer-bonded explosive under effects of transient stress waves

Cited by 43 publications

References 22 publications

Local Deformation and Failure Mechanisms of Polymer Bonded Energetic Materials Subjected to High Strain Rate Loading

Local Deformation and Failure Mechanisms of Polymer Bonded Energetic Materials Subjected to High Strain Rate Loading

Ignition criterion for heterogeneous energetic materials based on hotspot size-temperature threshold

Non‐Shock Ignition Probability of Octahydro‐1,3,5,7‐Tetranitro‐Tetrazocine‐Based Polymer Bonded Explosives Based on Microcrack Stochastic Distribution

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