Phenomenology of rapid projectile penetration into granular soils

Abstract Eighty subscale penetration tests were performed to investigate penetration phenomenology in granular media, with impact velocities in the range of 70–300 m/s. The parameter space consisted of (1) four natural and synthetic granular materials, including Ottawa sand, crushed fused quartz, aragonite, and crushed coral, (2) loose and dense packings, (3) dry and wet targets, and (4) four different projectiles, including spheres and long rods with conical, hemispherical and blunt nose shapes. Two techniques were employed to obtain penetration time histories, including photonic Doppler velocimetry for high velocity impact tests, and high speed imaging for low velocity impact tests. Penetration time histories were differentiated to obtain velocity and acceleration time histories. Analysis of the time histories revealed that the role of nose shape, packing density, and saturation is material dependent. Silica sands and calcareous sands showed contrasting behavior across the parameter space considered. These observations point to the significance of particle crushing in rapid penetration into granular media.

[1]  M. Iskander,et al.  Stress-strain behavior of sand at high strain rates , 2012 .

[2]  Magued Iskander,et al.  Terminal depth of penetration of spherical projectiles in transparent granular media , 2014 .

[3]  Stephan Bless,et al.  SAND PENETRATION BY HIGH‐SPEED PROJECTILES , 2009 .

[4]  R. Behringer,et al.  Collisional model for granular impact dynamics. , 2013, Physical review. E, Statistical, nonlinear, and soft matter physics.

[5]  Stephan Bless,et al.  Design and Performance of a Laboratory Pneumatic Gun for Soil Ballistic Applications , 2016, Experimental Techniques.

[6]  Magued Iskander,et al.  Photonic doppler velocimetry for study of rapid penetration into sand , 2014 .

[7]  A. Bragov,et al.  Quasi-steady motion of a solid in a loose soil with developed cavitation , 2013 .

[8]  N S Rad,et al.  FACTORS AFFECTING SAND SPECIMEN PREPARATION BY RAINING , 1987 .

[9]  Newton on objects moving in a fluid—the penetration length , 2008 .

[10]  David Z. Yankelevsky,et al.  Nose shape effect on high velocity soil penetration , 1980 .

[11]  Adam Collins,et al.  The effect of rod nose shape on the internal flow fields during the ballistic penetration of sand , 2011 .

[12]  Magued Iskander,et al.  A transparent aqueous-saturated sand surrogate for use in physical modeling , 2014 .

[13]  Magued Iskander,et al.  Design and Performance of a Laboratory Pneumatic Gun for Soil Ballistic Applications: Laboratory Pneumatic Gun for Soil Ballistics , 2014 .

[14]  Magued Iskander,et al.  Response of granular media to rapid penetration , 2014 .

[15]  W. Cooper,et al.  Grain fracture in rapid particulate media deformation and a particulate media research roadmap from the PMEE workshops , 2010 .