Projectile impact sensitivity

Explosives Sensitivity Data. Card-gap and projectile sensitivity, data are presented by Watson (Ref 1) for a wide variety of expl compns tested at the USBurMines laboratories in more or less standard test geometries. The results of both tests are in good agreement in that they provide the same sensitivity ordering fbr different subclasses of expls. Least sensitive were homogeneous liquids that did not exhibit a tendency, to undergo low-velocity detonation, AN-FO (Ammonium Nitrate-Fuel Oil), and most cast military expls. Of intermediate sensitivity were pressed and powdered military expls, cast Pentolite, permissible and nonpetmissible water-based expls, and one commercial two-component expl. The most sensitive were permissible and nonpermissible Dynamites and expls susceptible to low-velocity detonations Refs I) R.W. Watson, 1 Card-Gap and Projectile Impact Sensitivity Measurements, A Compilation , USBurMines Information Circular 1C 8605(1973)... 

The projectile impact sensitivity is the reaction of an explosive charge if hit by infantry projectiles. Impact safety is given if the charge does not fully explode at impact. The projectile impact sensitivity does not only depend on the type of explosive itself, but also on the nature of its confinement (metallic, plastic, thin-walled, or thick-walled). A single bullet impact by an ordinary or a hard steel cored projectile, or a machine gun burst, will create different reactions. 

The methods for the experimental determination of the fragment (or projectile) impact sensitivity of an explosive differ in details such as... 

We have thus far avoided distinguishing between impact sensitivity, projectile (or bullet) sensitivity and shock sensitivity which also involve impact loading of the test explosive. Shock sensitivity, as the name implies, is the response of an explosive to an externally generated shock. Measurements of shock sensitivity are very reproducible, although many existing measure-... 

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)... 

IIVX, 18, 45, 97, 117-118, 166, 215. See also Sub-VX,S- (2-dimethylaminomethyl)-o-ethyl methylphosphonothiolate, o-ethyl S- [2- (dimethylamino)methyl] -methylphosphonothioate Impact-sensitive material, 3, 23, 30, 45 6, 72, 116-117, 122, 136, 164 Improvised ANFO, 17-18 Improvised explosive, 19, 72, 164 Improvised explosive device, 183 Improvised explosive mixture, 17-18, 20, 22 Improvised military propellant, 27, 118, 140, 164 Improvised projectile propellant, 51, 71, 80, 152, 164... 

R,W.Lawrence J.E.Meyers, "Sensitiveness of High Explosives to Rifle Bui lets Experiment Station, Hercules Power Co, Wilmington, Del (1944) published as seen 1 in OSRD 3156(1944) 6)D.I.Hedrick, The Sensitivity to Projectile Impact of Explosives in Various Containers ,... 

Refs 1) Anon, Sensitivity of Explosives to Projectile Impact , OSRD 3156 (1944), Appendix A 2) D.P. MacDougall et al, Physical Testing of Explosives , OSRD 5745 (1945)... 

The Susan Sensitivity Test (Ref 7) is a projectile impact test with the projectile shown in Fig 1. The wt of expl in the projectile head is about 1 lb (0.45 kg). The target is armor-plate steel. The results of the tests are expressed in... 

Also propellant charges for rockets and guns have also been developed by compounding solid explosives such as nitramines (e.g. -> Cy-clonite) with plastics. Plastic explosives and plastic propellants are of interest, if low thermal and impact sensitivity is needed (- LOVA -> Armor Plate Impact Test -> Friction Sensitivity -> Heat Sensitivity - Impact Sensitivity -> Projectile Impact Sensitifity - Susan Test). 

High-velocity fragments, bullets, or projectiles impacting the explosive charges can cause their detonation. The determination of the sensitivity level of a given explcKive to such mechanical stimuli is of considerable practical interest. 

Moulard, Kury, and Delcos studied two special monomodal RDX polyurethane cast PBX formulations of 70 wt% RDX (either 6 micrometers or 134 micrometers medium particle size) and 30 wt% polyurethane. The shock initiation properties of these formulations were measured in thin plate impact, projectile impact, and wedge tests. The formulations containing the fine RDX were significantly less sensitive than those with coarse RDX at the same density of 1.44 g/cc, at least up to 100 kbar shock pressure. From these studies it was concluded that at the same density, the most shock-sensitive explosives are those with particle sizes between the coarse particles and the very fine particles. 

TNT is one of the least sensitive of military explosives only ammonium picrate, nitroguanidine, and ammonium nitrate are less sensitive. Impact tests yield high values relative to other military explosives, but impact sensitivity increases sharply with increasing temperature, as shown in table 8-56. Diminishing sensitivity has been reported down to- 196°C. Gap and projectile test results indicate cast TNT is less sensitive than the pressed materiel. Test results from the mod-... 

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