Monday  |  Pine/Spruce  |  05:10 PM–05:30 PM

#17555, High-Speed Ordnance Penetration into Stratified Sandy Soils

The majority of subscale ballistic penetration tests in granular media involve uniform materials, while natural soil deposits are frequently stratified. We present results of vertical projectile penetration tests in stratified sandy soils. We launch 14.3mm diameter cylindrical rod projectiles at velocities of approximately 200m/s vertically into stratified sand targets. Noses are either blunt or 60°cone. Sample preparation techniques are used to produce uniform and two-layered stratified soil targets with either loose or dense bulk packing densities equal to 1.58 g/cm3 and 1.82 g/cm3, respectively. Stratified targets comprise 10 cm and 20 cm deep loose sand overlaying dense sand, as well as 5 cm and 10 cm deep dense sand overlaying loose sand. A photon Doppler velocimeter (PDV) is used to resolve velocity as a function of time. The results of these experiments reveal gradual transitions in penetration behavior as the projectile approaches, encounters, and traverses the interface between the upper and lower soil layers. We define a sensing distance, which is the distance above the layer interface where the projectile is affected by the lower layer, to describe the transition from one layer to the next. The sensing distance is larger when projectiles travel from dense soil into loose soil. We demonstrate that this behavior in stratified soils can be captured within the Poncelet framework, by adding the sensing distance. The resulting formulation captures the projectile response in two-layered soil targets with reasonable accuracy.

Joseph Dinotte   Manhattan College
Mehdi Omidvar   Manhattan College
Stephan Bless   New York University
Magued Iskander   New York University