The Susan Projectile

Fig 1 The Susan projectile. Scaled drawing the high explosive head is 4" long by 2 in diameter (0.102m x 0.051m)... 

Scaled drawing of the SUSAN projectile. The high explosive head is 4 in. long and 2 in. in diameter (102 m x0.051 m). 

Initiation by Projectile Impact is a complicated process which depends on a combination of shock initiation, impact initiation and hot fragment initiation effects. For fast projectile impact, shock initiation effects are predominant. With slow projectiles the initiation resembles Impact Initiation. Further complications are introduced if the impacting projectiles are hot a special case where the explosive is part of the projectile is the so-called Susan Test—see Barrier Tests Their Comparison with Shooting Tests in Vo 4, pp D145-147 and Detonation (and Explosion) Experimental Procedures in Vol 4, pp 333-335... 

The object of the Susan Test is to compare the relative sensitivity of propints and expls under conditions of impact. It is performed by impacting a confined specimen at high velocities onto a steel plate. The driver is a 3-inch gun which imparts velocities ranging from 30 to 40m/s to the projectile. The results in terms of the kinetic energy of the projectile required for initiation are only of empirical value for reasons stated above (Ref 18, pp 2—20)... 

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... 

TNT shows no undesirable properties by the Susan test (Fig 2). Minor ignitions are seen down to about 235ft/sec (72m/s) impact velocity but only after extensive splitting of the projectile nosecap and abrupt halt of the projectile at the... 

Only a few tests fit the last two categories the only test that fits the last description is the Susan test [12], in which one pound of explosive in a special Projectile is driven against a hard target at selected velocities. It is really a form of impact test and is used only with secondary explosives. 

Fig 23 shows the deformation obtd soon after impact. The end of the AI nose cap has opened up, but the longitudinal section of the cap has not yet split open. Fig 24 shows the deformation late in the impact. The Al cap has completely failed by longitudinal splitting, and the steel rim of the projectile body is in near contact with the target plate. This is called the "pinch stage and the most violent reactions from a Susan type impact... 

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