Experimental investigations of the response of a portable container to blast, fragmentation, and thermal effects of energetic materials detonation

2021 ◽  
pp. 204141962110411
Author(s):  
Khurshid Ahmed ◽  
Abdul Qadeer Malik
Keyword(s):  
Blast Wave ◽  
Energetic Materials ◽  
Thermal Effects ◽  
Structural Damage ◽  
Energetic Material ◽  
Woven Fabric ◽  
Experimental Investigations ◽  
Filling Material ◽  
Arbitrary Lagrangian Eulerian ◽  
Blast Fragmentation

The detonation of an energetic material (EM) is manifested in the form of blast wave, fragmentation of casing material, and thermal effects. These effects are very destructive and cause injuries-being fatal-and structural damage as well. The attenuation of these effects is a prime focus. C4 explosive weighing 104 g was tested as surface burst. Peak overpressures of 1362 kPa and fireball radius of 0.65 m were measured. A multi-layer container comprised steel liner, Kevlar woven fabric, and laminated glass fiber reinforced polymer (GFRP) was developed and investigated to counter the combined blast, fragmentation, and thermal effects of EM detonation. Commercially available shaving foam was characterized and used as filling material inside the container. The foam bubbles have shown a good stability with time. The shaving foam quenched the fireball and afterburning reactions owing to rapid heat and momentum transfer mechanism. The containment system provided more than 80% overpressure reduction with respect to an equivalent open-air detonation and also restricted any escape to lateral directions. Coupled Euler-ALE (Arbitrary Lagrangian-Eulerian) approach was employed to numerically simulate the blast wave parameters. A good agreement is obtained between the simulation and experimental results.

Introduction of the acylamino group to bridged bis(nitroamino-1,2,4-triazole): a strategy for tuning the sensitivity of energetic materials

2021 ◽  
Vol 45 (38) ◽  
pp. 18059-18064
Author(s):  
Dongxu Chen ◽  
Jiangshan Zhao ◽  
Hongwei Yang ◽  
Hao Gu ◽  
Guangbin Cheng
Keyword(s):  
Energetic Materials ◽  
Energetic Material

Introduction of the acylamino group into energetic material compounds will contribute to balancing the sensitivity and the energy.

Structural interrogation using phase space topology of the wind-induced responses

2017 ◽  
Vol 24 (14) ◽  
pp. 3148-3172
Author(s):  
Riya C George ◽  
Sudib K Mishra
Keyword(s):  
Phase Space ◽  
Structural Damage ◽  
Model Building ◽  
Chaotic Signal ◽  
Experimental Investigations ◽  
Damage Scenarios ◽  
Space Topology ◽  
Frame Building ◽  
Low Dimensional ◽  
Phase Space Topology

The applicability of the phase space interrogation (PSI) methodology for structural health monitoring (SHM) is limited on account of the fact that the structure needs to be excited by a low dimensional chaotic signal. The present study demonstrates that the phase space interrogation can still be applied to structures subjected to ambient/moderate wind excitations. Key to this extension is the relative low dimensionality of the wind-induced structural responses, amenable to phase space embedding by virtue of Takens’ embedding theorem. The so-formed pseudo-attractor is shown to sufficiently reflect the changes in system dynamics induced by structural damage(s). A widely employed damage feature, namely, the changes in phase space topology (CPST) is subsequently employed to the reconstructed attractor to link it with the presence, severity, as well as localization of damage(s). The CPST is established as a legitimate damage-sensitive feature by studying its variability with alternative damage scenarios in a multistoried frame building subjected to wind excitations. The performance of the methodology is demonstrated under different degrees of noise contamination in the measured responses as well as varying intensity of wind speed. The statistical robustness of the procedure is also assessed. The numerical findings are supported by the evidence from a limited number of experimental investigations carried out on a model building with inflicted damage scenarios. The wind loadings for the tests are simulated using a wind tunnel testing facility. Finally, a simple analysis is presented that establish the viability of the phase space analysis analytically.

Achieving tunable chemical reactivity through photo-initiation of energetic materials at metal oxide surfaces

2020 ◽  
Vol 22 (43) ◽  
pp. 25284-25296
Author(s):  
Maija M. Kuklja ◽  
Roman Tsyshevsky ◽  
Anton S. Zverev ◽  
Anatoly Mitrofanov ◽  
Natalya Ilyakova ◽  
...  
Keyword(s):  
Metal Oxide ◽  
Chemical Reactions ◽  
Energetic Materials ◽  
Chemical Reactivity ◽  
Energetic Material ◽  
Oxide Surfaces ◽  
Oxide Interfaces ◽  
Metal Oxide Surfaces

Photo-stimulated chemical reactions in energetic materials can be highly controlled by selectively designing energetic material – metal oxide interfaces with tailored properties.

Solidification Heat Transfer and Base Separation Analysis in the Casting of an Energetic Material in a Projectile

2005 ◽  
Author(s):  
Dawei Sun ◽  
S. Ravi Annapragada ◽  
Suresh V. Garimella ◽  
Sanjeev Sing
Keyword(s):  
Heat Transfer ◽  
Finite Element ◽  
Numerical Model ◽  
Residual Stresses ◽  
Energetic Materials ◽  
Energetic Material ◽  
Complex Geometries ◽  
Experimental Measurements ◽  
Linear Temperature ◽  
High Prandtl Number

This paper investigates the problem of base separation in the casting of energetic materials in a projectile. Special challenges that arise in casting high Prandtl number energetic materials in projectiles of complex geometries are addressed. A comprehensive numerical model is developed by integrating finite volume and finite element methods to analyze the thermal and flow fields as well as the residual stresses. The predictions, which are confirmed by experimental measurements, suggest that sustenance of a linear temperature profile along the projectile axis can eliminate base separation, and also reduce residual stresses in the final casting.

scholarly journals Numerical Investigation of Sloshing in Rectangular Tank with Permeable Baffle

2020 ◽  
Vol 8 (9) ◽  
pp. 671
Author(s):  
Liting Yu ◽  
Mi-An Xue ◽  
Aimeng Zhu
Keyword(s):  
Permeability Coefficient ◽  
Structural Damage ◽  
Maximum Flow ◽  
Arbitrary Lagrangian Eulerian ◽  
The Finite Element Method ◽  
Resonant Frequencies ◽  
Cargo Transport ◽  
Violent Sloshing ◽  
Theoretical Results ◽  
Flow Velocities

Violent sloshing induced by excitation with large amplitudes or resonant frequencies may result in structural damage of the liquid-tank or even the overturning of the liquid cargo transport system. Therefore, impermeable and permeable vertical baffles were investigated numerically to suppress sloshing. The numerical simulations were based on the finite element method and arbitrary Lagrangian–Eulerian (ALE) method. The numerical model was verified by the available experimental data, numerical results and linear theoretical results. Based on the study of the effects of impermeable baffle height, amplitude and frequency of excitation on sloshing, the effects of baffle permeability on sloshing were investigated. Importantly, a critical permeability coefficient that was most effective to suppress sloshing was found. In addition, the maximum flow velocities in the tank with a baffle of small permeability coefficient were smaller than those in the tank with an impermeable baffle. While, the maximum flow velocities under a baffle of large permeability coefficient were larger than those in the tank with an impermeable baffle. Vortices were observed in the whole region of the baffle, tank bottom, tank walls and the free surface in the tank with a permeable baffle.

scholarly journals Nanostructured Energetic Materials with Sol-gel Methods

2003 ◽  
Vol 800 ◽  
Author(s):  
Alexander E. Gash ◽  
Joe H. Satcher ◽  
Randall L. Simpson ◽  
Brady J. Clapsaddle
Keyword(s):  
Thermal Properties ◽  
Energetic Materials ◽  
Energetic Material ◽  
Sol Gel ◽  
Small Scale ◽  
Fine Grained ◽  
Electron Microscopies ◽  
Burn Rate ◽  
Scanning Electron

AbstractThe utilization of sol-gel chemical methodology to prepare nanostructured energetic materials as well as the concepts of nanoenergetics is described. The preparation and characterization of two totally different compositions is detailed. In one example, nanostructured aerogel and xerogel composites of sol-gel iron (III) oxide and ultra fine grained aluminum (UFG Al) are prepared, characterized, and compared to a conventional micron-sized Fe2O3/Al thermite. The exquisite degree of mixing and intimate nanostructuring of this material is illustrated using transmission and scanning electron microscopies (TEM and SEM). The nanocomposite material has markedly different energy release (burn rate) and thermal properties compared to the conventional composite, results of which will be discussed. Small-scale safety characterization was performed on the nanostructured thermite. The second nanostructured energetic material consists of a nanostructured hydrocarbon resin fuel network with fine ammonium perchlorate (NH4ClO4) oxidizer present.

Kinetic Compensation Effect of Kinetic Parameters of Thermal Explosion Test

2012 ◽  
Vol 184-185 ◽  
pp. 1408-1417
Author(s):  
Ying Hui Shao ◽  
Zi Ru Liu ◽  
Xiao Ning Ren ◽  
Shu Yun Heng ◽  
Pu Yue ◽  
...  
Keyword(s):  
Kinetic Parameters ◽  
Thermal Explosion ◽  
Energetic Materials ◽  
Compensation Effect ◽  
Energetic Material ◽  
Regression Equation ◽  
Kinetic Temperature ◽  
Single Compound ◽  
Main Component ◽  
Explosion Test

The kinetic parameters of thermal explosion tests with five-second delay for 273 energetic materials were analyzed. The compensation effect exists between the two thermal explosion kinetic parameters of these energetic materials, e.g. lnA and Eb. The kinetic parameters of these energetic materials can be expressed by a single linear regression equation for the single compound or mixture under all conditions. The slopes of the regression equation for various systems are in the range from 0.1952 to 0.2413 (mol•kJ-1). The regression equation for single compound or mixture with one type of energetic material as main component has better linearity. Therefore, their “iso-kinetic temperature” Tik is close to their thermal explosion temperature Tb and the “iso-kinetic delay period”τik is also close to the 5 seconds.

Molecular Composition, Structure, and Sensitivity of Explosives

1992 ◽  
Vol 296 ◽  
Author(s):  
Carlyle B. Storm ◽  
James R. Travis
Keyword(s):  
Molecular Structure ◽  
Hot Spots ◽  
Energetic Materials ◽  
Physical State ◽  
Hot Spot ◽  
Energetic Material ◽  
Specific Situation ◽  
Reaction Products ◽  
Ambient Conditions ◽  
Delayed Reaction

AbstractHigh explosives, blasting agents, propellants, and pyrotechnics are all metastable relative to reaction products and are termed energetic materials. They are thermodynamically unstable but the kinetics of decomposition at ambient conditions are sufficiently slow that they can be handled safely under controlled conditions. The ease with which an energetic material can be caused to undergo a violent reaction or detonation is called its sensitivity. Sensitivity tests for energetic materials are aimed at defining the response of the material to a specific situation, usually prompt shock initiation or a delayed reaction in an accident. The observed response is always due to a combination of the physical state and the molecular structure of the material. Modeling of any initiation process must consider both factors. The physical state of the material determines how and where the energy is deposited in the material. The molecular structure in the solid state determines the mechanism of decomposition of the material and the rate of energy release. Slower inherent reaction chemistry leads to longer reaction zones in detonation and inherently safer materials. Slower chemistry also requires hot spots involved in initiation to be hotter and to survive for longer periods of time. High thermal conductivity also leads to quenching of small hot spots and makes a material more difficult to initiate. Early endothermic decomposition chemistry also delays initiation by delaying heat release to support hot spot growth. The growth to violent reaction or detonation also depends on the nature of the early reaction products. If chemical intermediates are produced that drive further accelerating autocatalytic decomposition the initiation will grow rapidly to a violent reaction.

Energetic materials: α-NTO crystallizes as a four-component triclinic twin

2005 ◽  
Vol 61 (5) ◽  
pp. 577-584 ◽  
Author(s):  
Nadezhda Bolotina ◽  
Kristin Kirschbaum ◽  
A. Alan Pinkerton
Keyword(s):  
Energetic Materials ◽  
Crystal Packing ◽  
Energetic Material ◽  
Data Sets ◽  
Flat Chain ◽  
Planar Molecules ◽  
Triclinic Unit Cell ◽  
Symmetry Space ◽  
Symmetry Space Group ◽  
Additional Hydrogen

The prevalent polymorph of the energetic material 5-nitro-2,4-dihydro-1,2,4,-triazol-3-one, α-NTO, crystallizes as a four-component twin with triclinic symmetry (space group P\bar 1). All crystals under investigation were fourlings, i.e. they contained each of the four possible twin components. Complete data sets were collected for two crystals, one with a predominant amount of one individual component (55%) and one with approximately equal volumes of each component. In both cases the fourling components are related by the twofold axes inherent in the holohedral symmetry of a pseudo-orthorhombic superlattice with a o = a t , b o = b t and c o = a t + b t + 2c t . The triclinic unit cell contains four crystallographically independent planar molecules in the asymmetric unit, each of which forms a hydrogen-bonded flat chain parallel to a t . Pairs of chains are combined into planar ribbons by additional hydrogen bonds. Thus, two independent ribbons extend parallel to a t , creating a dihedral angle of ∼ 70°. The origin of the twinning is derived from consideration of the crystal packing and the hydrogen-bonding scheme.

The thermochemistry and reaction pathways of energetic material decomposition and combustion

1992 ◽  
Vol 339 (1654) ◽  
pp. 365-376 ◽  
Keyword(s):  
Condensed Phase ◽  
Energetic Materials ◽  
Energetic Material ◽  
Theoretical Method ◽  
Chemical Processes ◽  
Reaction Pathways ◽  
Quantum Chemical Methods ◽  
Solvation Energies ◽  
Moller Plesset ◽  
Ignition And Combustion

The chemical processes involved in the decomposition and combustion of energetic materials have been investigated theoretically using quantum chemical methods to determine the thermochemistry and reaction pathways. The Bond-Additivity-Corrected Moller-Plesset fourth-order perturbation theory method (BAC-MP4) has been used to determine heats of formation and free energies of reaction intermediates of decomposition and combustion. In addition, the BAC-MP4 method has been used to determine reaction pathways involving these intermediates. A theoretical method for calculating solvation energies has been developed to treat the non-idealities of high pressure and the condensed phase. The resulting chemical processes involving decomposition, ignition and combustion are presented for nitramines and nitromethane. Differences in decomposition mechanisms for the condensed phase and gas phase are discussed. In addition, we discuss the effects that amines can have on the initial stages of condensed-phase nitromethane decomposition. Bond dissociation energies for nitro-triazoles are compared with those of other nitro compounds.

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