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|Title:||Penetration of projectiles into frozen ground|
Livingston, Clifton W.
Waldron, Howard L.
|Publisher:||Cold Regions Research and Engineering Laboratory (U.S.)|
Engineer Research and Development Center (U.S.)
|Series/Report no.:||Technical report (Cold Regions Research and Engineering Laboratory (U.S.)) ; 93.|
Summary: During 1960 and the first half of 1961, Barodynamics, Inc., designed, manufactured, and field tested 105 bombs specially designed to penetrate deeply frozen ground. The bombs were divided in three series: 2.50 in. diam. (approx 30 lb. each), 2.75 in. diam. (approx 40 lb. each), and 3.25 in. diam. (approx 66 lb. each). These bombs (29 of each series) were made geometrically similar to eliminate shape as a variable. In addition, 3 bombs of each diameter were made shorter and 3 longer in order to check the effect - of different geometry. Bomb design called for certain manufacturing innovations, mainly cementing together bomb parts with an epoxy adhesive, and use of a plastic tail fin. Because of the need for high penetrating ability at striking velocities of 800ft/sec or less, the design was extreme in two respects: slenderness of the bomb body, and sharpness of the nose. Because it was desired that the bombs impact the earth with as nearly 0 degree angle of yaw as possible, a relatively large and light fin and a large righting moment arm were incorporated into the design. The 30 live bombs were filled with Composition C explosive. The 75 inert bombs were filled with a sand-perlite concrete of the same cured density as the explosive. During three field tests, bombs were dropped from helicopters into unfrozen, shallowly frozen, and deeply frozen ground at striking velocities ranging from 252 to 800 ft/sec; penetrations up to 25 ft were achieved. Data concerning design, manufacture, and field tests, and their results are presented. For a given bomb penetrating a given material, penetration of the nose in feet is shown to be a straight-line function of striking velocity in feet per second. This is in accordance with the Livingston penetration equation, the basis of design.
|Rights:||Approved for public release; distribution is unlimited.|
|Appears in Collections:||Technical Report|
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|CRREL-Technical-Report-93.pdf||20.98 MB||Adobe PDF|