Effect of viscoplasticity on ignition sensitivity of an HMX based PBX

Hardin, D. Barrett; Zhou, Min

doi:10.1063/1.4971611

Cited by 6 publications

(8 citation statements)

References 9 publications

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“…The parameters of the material model for HMX are calibrated to match the experimental wave profile obtained by Dick et al (2004). The verification of the calibrated parameters is described in literature (Hudson et al 2012, Hardin 2015. Since the magnitudes of parameters used to describe the elastic-viscoplastic constitutive equations are calibrated and verified with experimental results on real HMX, the constitutive model takes into account the overall effect of voids and defects on the mechanical response of HMX.…”

Section: Methodsmentioning

confidence: 99%

“…In order to resolve the issue of one bulk element penetrating into another after the adjoining cohesive elements fail, a multi-step contact algorithm is used. Detailed descriptions of the multi-step contact algorithm which includes calculations of penetration depth and surface traction are given by Hardin (2015). We apply penalty forces to the contacting surfaces to strongly discourage or prevent interpenetration.…”

Section: Methodsmentioning

confidence: 99%

“…In the paper, we computationally analyze the response of MMXs to dynamic loading in an effort that can be considered as computational design and exploration of a class of materials that are not yet in existence. Hardin (2015) first performed a systematic numerical study on the hotspot dynamics of HEMs with Al alloys as matrix in place of Estane in a PBX. They named the new system of HEM as aluminum-bonded explosives.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Computational study of ignition behavior and hotspot dynamics of a potential class of aluminized explosives

Roy

Kim

Miller

et al. 2018

Modelling Simul. Mater. Sci. Eng.

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The ignition behavior and hotspot dynamics of a potential class of aluminized energetic materials are studied computationally. The materials consist of HMX (octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine) grains embedded in an aluminum matrix and, henceforth referred to as metal-matrix explosives (MMXs). For the analysis, two different MMXs, the soft MMX with a matrix of 1100 Al alloy and the hard MMX with a matrix of 7075 T651 Al alloy are considered. The thermo-mechanical response of the MMXs are computationally analyzed by subjecting them to monotonic impact loading using a Lagrangian cohesive finite element framework, with their ignition behavior analyzed through characterization of hotspots. For comparison, a polymerbonded explosive (PBX) consisting of HMX and Estane is also analyzed under the same conditions. The results show that the MMXs have significantly lower propensity for ignition and higher structural integrity than the PBX over the loading velocity range of 200-500 m s −1 .

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Computational study of ignition behavior and hotspot dynamics of a potential class of aluminized explosives

Roy

Kim

Miller

et al. 2018

Modelling Simul. Mater. Sci. Eng.

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“…Most models tend to focus only on the viscoelasticity of the binder, assuming the granular phase is either rigid or elastic. Hardin and Zhou [35] examined this assumption by means of a theoretical study that treated HMX crystals in a PBX as either elastic or viscoplastic. Their results suggest that if the crystals are elastic, they would have a lower impact ignition threshold.…”

Section: Sensitivity Of Energeticsmentioning

confidence: 99%

Vibration-Induced Heating of Energetic Materials: A Review

Perry

Walley

2021

J. dynamic behavior mater.

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The transport of energetic materials—whether by truck over rough terrain, or attached to the undercarriage of a high-performance jet aircraft—carries a certain level of inherent risk as the repeatedly applied stresses from vibration may lead to heating, mechanical degradation, and potentially even the triggering of an ignition event. Increasing knowledge of the underlying physics which control ignition is allowing us to better understand, and thus reduce, the risk of a catastrophic event occurring. The Apollo and Space Shuttle programmes provided motivation for research into the topic in the 1960s and 1970s, and some recent studies have focussed on the grain-scale physics of ignition. However, much of the useful insight has arisen from work with other primary applications in mind. Therefore, this review aims to bring together literature from several fields, with the intention of better understanding vibration-induced heating (VIH) phenomena in energetic materials. Sensitivity, VIH in viscoelastic polymers and inert composites, and a technique known as vibrothermography which uses VIH to detect cracks, are all considered where relevant read-across can be found. Often being viscoelastic materials and composites with complex rheology, energetic materials subjected to vibrational loading tend to warm up, with potential for even greater temperature rises due to anisotropy-driven localised heating mechanisms. Binders soften as temperature rises, and the chance of damage increases, which may lead to runaway heating and thermal failure (if mechanical failure does not occur first).

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“…A second approach to friction uses cohesive elements [23][24][25][26]. A tensile separation law between the elements allows on the one hand the appearance and propagation of cracks, and on the other hand the grain-matrix decohesion and friction between the two phases.…”

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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Effect of viscoplasticity on ignition sensitivity of an HMX based PBX

Cited by 6 publications

References 9 publications

Computational study of ignition behavior and hotspot dynamics of a potential class of aluminized explosives

Computational study of ignition behavior and hotspot dynamics of a potential class of aluminized explosives

Vibration-Induced Heating of Energetic Materials: A Review

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

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