Projectile testing

Mortar Projectile Test (7) Bomb Drop Test (7) Fragmentation Test (7-8) Fragment Velocity Test (8) Blast Effect (8) Shaped Charge Effectiveness (8) Hydrolysis by 240 Hour Test (9) Sensitivity to Initiation by Electrostatic Discharge (9 10)... 

Impact Safe Distance (Projectile) Test 208 is briefly described in Vol 4, p D1094-L... 

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-... 

While projectile testing is common, the tests and equipment are not standardized. In general, resin suppliers to do not provide any test data for projectile testing. Instead, projectile testing is usually done with customized equipment with a specific intent, such as evaluating the impact resistance of automobile fascia when impacted by road debris, or of aircraft windshields when subjected to bird strikes. 

The advantage of projectile testing is that the test can be developed to mimic the actual end-use conditions and materials can be evaluated in that context The disadvantage is that the equipment, and the actual tests, are not standardized, and it may not be possible to correlate the results of these tests with other types of toughness tests (Figure 5.14). 

The shrouds and exhaust chutes were made from tough materials like polycarbonate, ABS, occasionally even polypropylene. The key was projectile testing, specifically small objects weighing grams or ounces that were projected at fairly high speed. The performance requirements might vary, minor deformation allowed, no structural failure allowed, etc. While projectile testing can be a slow and tedious process, it can provide valuable information on performance in real-world applications. 

While some might think that the purpose of this demonstration was to prove the toughness of thermoplastics from GE Plastics, I prefer to think of it a subtle reminder of importance of projectile testing when evaluating the use of thermoplastics in an application subject to high velocity impacts. 

A unifonn monoenergetic beam of test or projectile particles A with nnmber density and velocity is incident on a single field or target particle B of velocity Vg. The direction of the relative velocity m = v -Vg is along the Z-axis of a Cartesian TTZ frame of reference. The incident current (or intensity) is then = A v, which is tire number of test particles crossing unit area nonnal to the beam in unit time. The differential cross section for scattering of the test particles into unit solid angle dO = d(cos vji) d( ) abont the direction ( )) of the final relative motion is... 

An electron or atomic beam of (projectile or test) particles A with density N, of particles per cm travels with speed V and energy E tln-ongh an infinitesimal thickness dv of (target or fielc0 gas particles B at rest with... 

Windows in airplanes, trains, and schools commonly use polycarbonate. Exotic appHcations include military use, for example in high speed aircraft canopies, where tests have shown polycarbonate to withstand impact with fowl at Mach 2. Polycarbonate is also used for security appHcations as laminates with glass or other materials. Polycarbonate offers unsurpassed projectile-stopping capabiHty, as the material softens upon impact with a bullet, absorbing the projectile s energy. 

Figure 9.20 shows the setup for a symmetric plate impact test. The projectile here has a facing plate of ceramic and is backed with a low-density foam, for support of the ceramic during launch. The facing plate of the target is also made of ceramic. The lithium fluoride slab, which backs the target sample, serves as a window for the laser velocity interferometer (VISAR) that measures the time-resolved particle velocity at the sample/window interface. 

Test data are available for two experiments at different impact velocities in this configuration. In one of the tests the projectile impact velocity was 1.54 km/s, while in the second the impact velocity was 2.10 km/s. This test was simulated with the WONDY [60] one-dimensional Lagrangian wave code, and Fig. 9.21 compares calculated and measured particle velocity histories at the sample/window interface for the two tests [61]. Other test parameters are listed at the top of each plot in the figure. 

The measurement of mechanical properties is a major part of the domain of characterisation. The tensile test is the key procedure, and this in turn is linked with the various tests to measure fracture toughness... crudely speaking, the capacity to withstand the weakening effects of defects. Elaborate test procedures have been developed to examine resistance to high-speed impact of projectiles, a property of civil (birdstrike on aircraft) as well as military importance. Another kind of lest is needed to measure the elastic moduli in different directions of an anisotropic crystal this is, for instance, vital for the proper exploitation of quartz crystal slices in quartz watches. 

P.B. Tweed J.D. Hopper, Study of Loading of MOX-2B Into 20mm Shell and Acceptance Tests of Cartridges Containing Projectiles Filled with this Explosive , PATR 1935 (11 May 1953)... 

In testing penetration of armor, etc, by various projectiles, they can be fired against armor plate of varying thickness and compn until the maximum depth of penetration is detd ... 

Projectile Sensitivity. Andreev Belyaev (Ref 32, p 473) showed that PA packed in wooden crates detonates if impacted by a 4g projectile moving at greater than 40Qm/sec. In the rifle bullet sensitivity test 0% explosions, 60% partials and 40% combustions were observed for PA (Ref 48)... 

C. Anderson R. Rindner, Separation Distances Tests of 155mm (Ml07) Projectiles , PATR4425 (1973) 16) R. Bassa G. Laszlo,... 

Inch Separation Propagation Tests for Cartridge, 81mm, HE, M374A2E1 and Projectile 81mm, HE, M374 , PATR 4773 (1975) 32) D.J. 

The ballistic mortar method is described briefly in Vol 1, p VII. Basically this test consists of firing a standard weight of expl (usually lOg) in a suspended mortar closed with a tightly fitting steel projectile. The angle of recoil of the mortar is measured and compared to the recoil produced by the same weight of a standard... 

Projectile, 155MM, Test, M692 Loading, Assembling and Packing... 

Projectile, 20MM, High Pressure Test, M54A1 MIL-P-46636C 26 Sep 73 MU... 

A relatively new class of fluorocarbon composite nronlrits with relatively high specific impulse and a high density impulse have been tested as booster rockets for 5-inch projectiles. 

Bir et al." have analyzed the effect of blunt ballistic impact of a baton-type, less-lethal projectile on the thoracic region using human cadavers. She determined human-response corridors and developed biomechanical surrogates, which can be used for testing different new projectiles for their blunt ballistic impact. The human-response force corridor for blunt thoracic impact by a thermoplastic polyurethane-based baton round with 37 mm diameter, weighing 30 g, and traveling... 

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