Elastic Detonation Wave

Detonation Wave, Elastic. An elastic wave is one which temporarily disturbs the medium thru which it traverses ie, after passage of the wave, the medium returns to its original state. Properties of elastic waves and of plastic waves were determined by Minshall (Ref 39) using pin contactors and crystals. Nawa (Ref 85) carried out theoretical and exptl studies on the transition of the energy generated by expls and the wave shapes of the generated elastic waves. The amplitude of an elastic wave was theoretically detd and experimentally correlated with sp energy and/or brisance of expls (See also Ref 92a) 

Detonation Wave, End Effect in. See under Detonation Wave Shape and Density Properties and in Ref 52, pp 91 98 (See p D727) 

Detonation Wave, Energy Exchange in. See Ref 80, listed on p D728 

Detonation Waves Experimental Procedures for Determination of their Properties. See Refs 3, 32, 35, 44, 57, 67, 68, 6 9,75, 94, 

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EL-389A, EL-389B, EL-389C 5 El9 Elastic detonation wave 4 D684... 

The transmission of such a stress will depend on the elastic nature of the material, and the optimum condition for transmission of the breaking wave is achieved in perfectly elastic materials, such as individual crystals. The soft, plastic or fluid materials which tend to damp out elastic waves have a similar tendency with detonation wave... 

Investigation at the Chemical Physics Institute of the Academy of Sciences has shown for large chge diameters of condensed expls, pressures of the order of 3.1C)5kg/cm2 arise in the detonation wave) 223 [Calcn of pressure from Van der Vaals equation of state p=RT/(v-b)] 224 (Assumption of Landau Stanyukovich that in the explosion products of Landau 8t Stanyukovich for a density in excess of 1 g/cm2 the main part of pressure is of elastic origin and depends only on the density of expln products, but not on the temp) 217 (Effect of pressure on thermal dissociation is discussed. In the case of condensed expls the pressure indirectly affects the molecular separation and alters the rate of chemical reaction. Experiments of Yu.N. Riabinin have shown that the reaction rate was diminished at a high pressure, up to 5.10 kg/cm2)... 

Detonation Wave, Plastic. These waves are complicated by the fact that there is no longer a linear relation between stress and strain. A plastic wave does not maintain its form as it progresses but rather the front of increasing stress tends to become longer and longer, at least in normal cases. The reflection at a discontinuity resembles generally the reflection of an elastic wave. Reflection of stress wave at a fixed end in an elastic member gives rise to stresses strains that ass exactly double those in the incident wave... 

CA 49, 10625 (1955) (Structure of detonation wave front of gases was studied by method of shock tube) (See its abstract under Detonation Wave Structure) 38a) R.E. Duff E. Houston, 2nd ONRSympDeton (1955), p 225 (See under Detonation Wave Structure Measurements in Condensed Explosives) 39) S. Minshall, JApplPhys 26, 463- 69 (1955) (Properties of elastic and plastic waves determined by pin contactors and crystals) 40) C.G. Dunkle, "Introduction to Theory of Detonation of Explosives, Syllabus of 21 Nov 1955 and Lecture Delivered at Picatinny Arsenal on 13 Dec, 1955 (Structure of the deton wave)... 

Munson, "The Influence of Mechanical Properties on Wave Propagation in Elastic-Plastic Materials, Ibid, pp 295-304 93) F. David et al, "Oblique Impact of a Layer of Explosive by a Metal Plate , Ibid, pp 381-85 (Formation of oblique deton wave and of over-detonation wave by such impact)... 

For technical purposes, underwater gas mixture detonations were triggered in a half-closed vessel (explosive chamber) or a spherical charge confined in a thin elastic shell. A simple configuration explosive chamber is a vertical half-closed duct (tube) with its open end submerged in a liquid. The depth of immersion can be varied. The pressure wave amplitude, which is generated by the reflection of a detonation wave from the explosive mixture-water boundary, grows in proportion to the gas mixture density [44]. 

Detonation is the progressive breaking of the valence bond by a stress, known as breaking stress, which is transmitted thru the material as an elastic wave similar to... 

The sensitivity of expls is a characteristic of great importance and can be correlated with the rate of deton. Perfect crysts and other nearly perfect elastic materials are the most sensitive, while liquids or colloids (plastic, fluid or hard) resist initiation and also have tendency to damp out-the wave of deton. The sensitivities of endothermic and exothermic compds are different and this causes them... 

Fairbanks A.G. Gaydon, Nature 175, 253-54(1955) (Comparison of the spectra produced by shock waves, flames and detonations) 31) W.A. Allen et al, JAppl-Phys 26, 125-26(1955)(Shock waves in air produced by elastic waves in a plate)... 

The disturbance in seawater travels rapidly outward, creating a growing spherical cavity. The traveling gas-liquid interface is known as the detonation front. Seawater is not an ideal elastic solid but has a bulk modulus that is a fxmction of pressure. The seawater as it is compressed becomes stiffen Therefore, the velocity of the outward traveling shock wave is a function of the peak pressure of the new wave. As the wave travels outward, the peak pressure decreases as a negative power of radial distance from the source. The value of the negative power decreases from typically -3 to -1.3 with distance from the source (Kramer et al., 1968 Dobrin, 1976). When the initial positive pressure pulse reaches a free water surface, it is reflected as a pulse of opposite polarity. 

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