Initial stage of ignition process in powder explosive with a closed end

Khrapovskii, V. E.

doi:10.1007/bf00755867

Cited by 6 publications

(4 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The stages of the mechanism bear similarities to other mechanisms that have been proposed for tetryl, 11 picric acid, [14][15][16] and some propellants, 12,13 but the combination that has been found in PETN in this study is new. The stages in the mechanism are a conductive burn which rapidly becomes a convective burn.…”

Section: Discussionsupporting

confidence: 81%

See 1 more Smart Citation

A new mechanism for deflagration-to-detonation in porous granular explosives

Gifford¹,

Luebcke²,

Field³

1999

Journal of Applied Physics

View full text Add to dashboard Cite

show abstract

Section: Discussionsupporting

confidence: 81%

“…[14][15][16] This mechanism has been shown to occur in these materials when they are in a high porosity charge composed of small particles. Described as a type II transition the principle feature of this process is a double wave structure in which the leading convective wave is followed by a high velocity post- convective wave.…”

Section: Introductionmentioning

confidence: 97%

A new mechanism for deflagration-to-detonation in porous granular explosives

Gifford¹,

Luebcke²,

Field³

1999

Journal of Applied Physics

View full text Add to dashboard Cite

show abstract

“…However, if the density and particle size of some high explosive powders are below certain critical values, an alternative mechanism comes into play where a burning channel forms along the entire length of the column. 126,[139][140][141][142][143][144][145][146][147][148] Rapid reaction then begins at a random location in this channel and proceeds in both directions. 126 Note that both these sets of experiments were conducted on relatively novel ultrafine powders of PETN.…”

Section: Ddt and Sdt Studiesmentioning

confidence: 99%

Crystal sensitivities of energetic materials

Walley¹,

Field²,

Greenaway³

2006

Materials Science and Technology

116

View full text Add to dashboard Cite

Organic and inorganic explosives were first developed and put into service in the 19th century, before there was much understanding of how the energy release mechanisms differed from those of the long established gunpowder. Theoretical advances in the understanding of shock waves combined with improvements in photographic and electronic techniques led to the hypothesis that a detonation is a shock wave maintained by the rapid release of chemical energy. Studies of accidental ignitions/initiations showed that explosive events can occur even when the energy input is much less than that required to heat the bulk explosive to the deflagration temperature. Hence, the highly fruitful idea of the localised hot spot was conceived. Apart from electrical stimuli, the main hot spot mechanisms are currently accepted as being adiabatic asymmetric collapse of gas spaces (producing gas heating, jetting, viscoplastic work) and the rubbing together of surfaces as in friction or adiabatic shear. Initiation mechanisms are also connected with the anisotropy of plasticity and fracture in explosive crystals. Decomposition of molecules can take place as they are forced past each other in a deforming crystal. There is, however, still much to discover about reaction pathways. Novel optical and electron microscopy techniques have given a great deal of new and precise information about displacements and failure mechanisms when explosive crystals are bonded together using polymers. The deflagration-detonation transition (DDT) has been extensively studied in model one-and two-dimensional systems.

show abstract

“…Two types of deflagration-to-detonation transition (DDT) have been identified in columns of explosive materials composed of small crystals [61][62][63]. Which one occurs has been found to depend upon the density of packing (porosity).…”

Section: Deflagration-to-detonation Transition (Ddt)mentioning

confidence: 99%

The Shock Initiation and High Strain Rate Mechanical Characterization of Ultrafine Energetic Powders and Compositions

et al. 2003

View full text Add to dashboard Cite

This paper reviews the techniques that have been developed at the Cavendish Laboratory for the study of the mechanical and ignition properties of energetic materials. HIGH-SPEED PHOTOGRAPHYA number of techniques have been developed and applied in our laboratory for the investigation of the properties of energetic materials. One method we have used in a wide range of such studies has been high-speed photography e.g. refs [1][2][3][4][5][6][7][8][9][10][11]. The advantage is that it is possible to see directly what is going on in, for example, hot spot initiation of energetic materials.In recent years, it has increasingly been desired to model the impact response of structures containing energetic materials using numerical methods. If meaningful numerical results are going to be obtained for, say, munitions or rockets, it is of vital importance that constitutive relations be constructed which describe the mechanical response of unreacted energetic materials over the temperature and strain rate ranges of interest. With this in mind, we have developed a range of techniques for obtaining the mechanical properties of energetic materials over a wide range of strain rates and temperatures. Examples of publications where such data have been published include refs [4, 7, 12-20].One problem with conventional mechanical testing methods is that they only allow the measurement of the global response of a specimen. Energetic materials usually consist of a viscoelastic binder heavily loaded with explosive crystals. In order to develop realistic and physically-based constitutive models for such unusual composites, it is vital to determine how these materials deform on the mesoscale. To this end, we have developed a range of optical and microscopy techniques. These have been used for both quasistatic [14, 15,18,[21][22][23] and dynamic studies [19,20,[24][25][26]. HOPKINSON BARSThe split Hopkinson pressure bar (SHPB) is one of the most widely used machines for obtaining the stress-strain properties of materials at high rates of deformation (10 3 -10 4 s -1 ) [27,28]. Our initial work in this area was to develop a miniaturised direct impact system (DIHB) allowing strain rates between 10 4 and 10 5 s -1 to be accessed [29,30]. A larger DIHB was later developed to obtain the high rate mechanical properties of polymer-bonded explosives (PBXs) and polymers [7, 31]. In recent years, we have constructed a suite of conventional SHPBs of various mechanical impedances so as to be able to measure the high rate properties of materials

show abstract

Initial stage of ignition process in powder explosive with a closed end

Cited by 6 publications

References 0 publications

A new mechanism for deflagration-to-detonation in porous granular explosives

A new mechanism for deflagration-to-detonation in porous granular explosives

Crystal sensitivities of energetic materials

The Shock Initiation and High Strain Rate Mechanical Characterization of Ultrafine Energetic Powders and Compositions

Contact Info

Product

Resources

About