TNT explosives

Figure 4.18. Peak side-on overpressure due to a surface TNT explosion according to Marshall (1976). (TNT in kilograms.)...

TNT explosions have a very high shock pressure close to the blast source. Because a shock wave is a non-isentropic process, energy is dissipated as the wave travels from the source, thus causing rapid decay of overpressures present at close range. 

The impulse at close range from a pressure vessel burst is greater than a TNT explosion with the same overpressure. Therefore, it is conservative to use... 

Calculate the total burning time of tlie octane pool in Illustrative Exatiiple 3. Calculate tlie peak overpressure of a 50-pound TNT explosion at a distance 200 feet from the ignition point, if tlie peak oi erpressure at 1000 feel is 0.10 psi when 150 pounds of TNT is detonated. 

Impact Sensitivity, PicArsn app with 2kg wt, 17" vs 14" for TNT Explosion temp. About 315°... 

Potential Changes Associated with Large Scale TNT Explosions , Rept No DRES-TN-203, DREstbmt, Suffield (Can) (1969) R) J.A. Scanlan, "TOW , MTR-No 86, 1-30, Contract DAAH01-70-C-0097, Hughes Aircraft Co, Culver City (1969) S) R.L. Jameson et al, Mortar Shell Vulnerability , Rept No BRL-MR-2029 (1970) T) G.A. Schroeder, Experimental... 

Figure A.3. Positive phase shock wave parameters for a hemispherical TNT explosion on the surface at sea level (Ref. 7).

A proportion of finely divided aluminium is often added to TNT explosives in order to increase the power. As aluminium has also a sensitising effect, it is particularly useful in waterproofed compositions. Another power producing additive which is sometimes employed in large diameter charges where its slow reaction is of less disadvantage is calcium silicide. Care must be taken with this material, however, to ensure that it does not lead to sensitiveness to friction and impact. 

Figure 6-23 Correlation between scaled distance and explosion peak side-on overpressure for a TNT explosion occurring on a flat surface. Source G. F. Kinney and K. J. Graham, Explosive Shocks in Air (Berlin Springer-Verlag, 1985).

The data in Figure 6-23 are valid only for TNT explosions occurring on a flat surface. For explosions occurring in the open air, well above the ground, the resulting overpressures from Figure 6-23 are multiplied by 0.5. Most explosions occurring in chemical plants are considered... 

The most destructive incidents in the petroleum and related industries are usually initiated by an explosive blast that can damage and destroy unprotected facilities. These blasts have been commonly equated with the force of a TNT explosion and are quite literally a "bomb". The protection of hydrocarbon and chemical industries is in rather a unique discipline by itself, which requires specialized techniques of mitigation and protection in a systems based approach. The first step in this approach is to understand the characteristics of hydrocarbon releases, fires and explosions. 

All mathematical models require some assumed data on the source of release for a material. These assumptions form the input data which is then easily placed into a mathematical equation. The assumed data is usually the size or rate of mass released, wind direction, etc. They cannot possibly take into account all the variables that might exist at the time of the incident. Unfortunately most of the mathematical equations are also still based on empirical studies, laboratory results or in some cases TNT explosion equivalents. Therefore they still need considerable verification with tests simulations before they can be fully accepted as valid. 

In the free field, the blast wave from an explosion travels at or above the acoustic speed for the propagating medium. TM 5-1300 provides plots of shock front velocity vs. scaled distance for high energy TNT explosives. There are no similar plots available for pressure wave propagation. However, for design purposes it can be conservatively assumed that a pressure wave travels at the same velocity as a shock wave. In the low pressure range, and for normal atmospheric conditions, the... 

Results of Paterson s work show that the receptor (PETN) is considerably overprimed by the NG based expl, and slightly under-primed by the TNT based expl. The. reflected wave is in each case a rarefaction, very weak with the TNT explosive. The condition for no reflected wave is that the primer C-J point lie on the receptor RH curve. The condition for a stable wave in the receptor is that the receptor CJ point lie on the primer RH curve while the condition for exactly balanced priming is that the two CJ points coincide. The last condition is satisfied at every section in a single expl cartridge Fig 2 shows also, for comparison, the transmitted RH curve for nonreactive waves. The properties of such waves transmitted by the same two primers are summarized by Paterson in the table, but this part is omitted bv Dunkle and by us... 

The values a=0.25 and j8 = 0.30, which were chosen originally in 1943 to give agreement with experimental data, then available, proved later to be inadequate. It was found by Cowan Fickett that the value /S = 0.30, used by Kistiakowsky Wilson, proved to be too high to match the observed slopes of D-po curves for RDX/TNT explosives. 

Shoeiyaku. Pentaerythritol Tetranitrate (PETN), C(CH2ON02)4 mw 316.14, N 17.72% wh crysts, d 1.77, mp 141° Brisance by Plate Dent Test 129% TNT Explosion Temperature 225° (decomp in 5 secs) Impact Sensitivity BurMines-App, 2-kg Wt 17cm (vs 100+ for TNT) Power by Ballistic Mortar Test 145% TNT Rate of Detonation 8300m/sec (Ref 8, p 276). Pressed PETN was used in Army 7.7 12.7-mm Fuzeless Projectiles and 20-mm MG Projs. Also in Boosters. Its mixt with TNT is called Pentoriru (qv). PETN with 8.5% wax was used for loading 20-mm Shells. Its mixtures with RDX were used in 7.7 12.7-mm Projectiles. PETN was also used in Incendiary Mixtures (Ref 1, p 27 Ref 5, p 372)... 

Brisance by Sand Test — 0.4g crushed 36.6S sand vs 48.0 by TNT Explosion Temperature — 345°... 

Wexes in Cast TNT Explosives Composition B (see Vol 3, C477—C484 Refs 92 106)... 

Explosive and Other Properties(Refs 6,8,9,11,13, 14,15,19,20,22,24, 33) Brisance by Sand Test, 110% of TNT by Lead Plate Cutting Test, about equal to PA by Lead Block Compression Test, 111% TNT and by Copper Cylinder Compression Test 114% TNT Explosion temperature, 2CP Heat of Combustion, at 17°, 3096cal/g(Ref... 

Its expl and other props, given in R.efs 2,3,4 5), are as follows Ballistic Mortar Value (Power) 127%TNT Explosion Temperature ignites ca 340°, but does not expl even at 360° (same as for TNT) Friction Sensitivity- si less sensitive than RDX Heat of Combustion, Qc 769.8 kcal/mole Heat of Explosion, Qe 272.6 kcal/mole Heat of Formation, 27.8 kcal/mol Hygroscopicity- increase in wt at 100% RH 0.09% vs 0.03% for TNT not hygroscopic at 90% RH Impact Sensitivity, detd by BurMinesApp No 5- si less sensitive than PETN 75° International Heat Test loss of wt in 48 hrs 0.1% vs 0.2% for TNT Power- see Ballistic Mortar Value and Trauzl Value Stability. Thermal at 100°- no expln in 300+ mins(same as for TNT) Stability, Thermal at 2 35°- methyl violet turned salmon pink in 30 mins vs 300+ mins for TNT Temperature of Explosion 3885°K Trauzl Test Value 135% TNT ... 

Connor J. Wisotski, The Early Optical Spectrum and Airshock from a 500-Ton TNT Explosion , NOLTR-67-94 (1967), (AD 662 404)... 

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