Mesoscale analysis of volumetric and surface dissipation in granular explosive induced by uniaxial deformation waves

Panchadhara, Rohan; Gonthier, Keith A.

doi:10.1007/s00193-010-0287-6

Cited by 43 publications

(21 citation statements)

References 34 publications

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“…One reason for this discrepancy is that these simulations ignore damage in the microstructures and heat generation owing to frictional dissipation at crack surfaces and sliding interfaces. Panchadhara & Gonthier (2011) studied the compaction of granular explosives under uniaxial compression, using a Lagrangian finite and discrete element technique. Contact and friction across neighbouring grains are considered.…”

Section: Introductionmentioning

confidence: 99%

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

2012

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The effect of transient stress waves on the microstructure of HMX-Estane, a polymerbonded explosive (PBX), is studied. Calculations carried out concern microstructures with HMX grain sizes on the order of 200 mm and grain volume fractions in the range of 0.50-0.82. The microstructural samples analysed have an aspect ratio of 5 : 1 (15 × 3 mm), allowing the transient wave propagation process resulting from normal impact to be resolved. Boundary loading is effected by the imposition of impact face velocities of 50-200 m s −1 . Different levels of grain-binder interface strength are considered. The analysis uses a recently developed cohesive finite element framework that accounts for coupled thermal-mechanical processes involving deformation, heat generation and conduction, failure in the forms of microcracks in both bulk constituents and along grain/matrix interfaces, and frictional heating along crack faces. Results show that the overall wave speed through the microstructures depends on both the grain volume fraction and interface bonding strength between the constituents and that the distance traversed by the stress wave before the initiation of frictional dissipation is independent of the grain volume fraction but increases with impact velocity. Energy dissipated per unit volume owing to fracture is highest near the impact surface and deceases to zero at the stress wavefront. On the other hand, the peak temperature rises are noted to occur approximately 2-3 mm from the impact surface. Scaling laws are developed for the maximum dissipation rate and the highest temperature rise as functions of impact velocity, grain volume fraction and grain-binder interfacial bonding strength.

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Section: Introductionmentioning

confidence: 99%

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

2012

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“…Additional details about the constitutive theory can be found in Ref. 3 Computations are performed using a combined finite and discrete element method that is well-suited for problems involving heterogeneity. This combined method uses the finite-element method (FEM), coupled with a radial return stress update algorithm, to numerically integrate the time-dependent, 2-D conservation principles and viscoplastic flow rule governing deformation of individual particles, and uses the discreteelement method (DEM) to account for interactions between particles.…”

Section: Computational Techniquementioning

confidence: 99%

Meso-Scale Computation of Uniaxial Waves in Granular Explosives-Analysis of Deformation Induced Ignition

Gilbert

Gonthier

2012

50th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition

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Deformation induced ignition of heterogeneous solid explosives is believed to originate at hot-spots within the material which are local regions of elevated temperature resulting from dissipative mechanisms such as plastic deformation and inter-particle friction. Inert mesoscale modeling of these materials can principally account for hot-spot formation enabling the characterization of hot-spot size and temperature distributions which are important for ignition but are difficult to experimentally resolve. By combining inert heating predictions for uniaxial waves with thermal explosion data and analysis, ignition time distributions and local fractions of ignited mass can be estimated as a function of wave strength for a given initial meso-structure (i.e., particle size and shape distribution, porosity, etc.). This information may then be used with a stochastic theory to establish the early time (or local) ignition kinetics of the material as a function of wave strength. The stochastic theory is an extension of the theory first developed by Terao 5 to estimate the ignition probability of reactive gas mixtures based on measured thermal explosion time data. This study represents a preliminary step in establishing a general framework for characterizing early time shock ignition of energetic solids and its dependence on meso-structure based on inert meso-scale computations.

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“…Here, it is noted that although the underlying granular microstructure also depends on particle morphology, the only variable available in the multiphase model used to describe this microstructure is φ i . Efforts to include mesoscale physics within the continuum macroscale description have been attempted [5], but require additional submodeling such as mesoscale simulations [1,2,4,6,32], which is beyond the scope of this work. The gas internal energy is characterized by its thermal equation of state e g = e g (ρ g , P g ), while the solid equation of state includes a volume fraction contribution due to compaction, i.e., e i = e i (ρ i , P i , φ i ).…”

Section: Introductionmentioning

confidence: 99%

A multi-phase theory for the detonation of granular explosives containing an arbitrary number of solid components

Crochet

Gonthier

2015

International Journal of Multiphase Flow

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Mesoscale analysis of volumetric and surface dissipation in granular explosive induced by uniaxial deformation waves

Cited by 43 publications

References 34 publications

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

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

Meso-Scale Computation of Uniaxial Waves in Granular Explosives-Analysis of Deformation Induced Ignition

A multi-phase theory for the detonation of granular explosives containing an arbitrary number of solid components

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