PENETRATION STUDIES OF ICE WITH APPLICATION TO ARCTIC AND SUBARCTIC WARFARE

• Main Author: Ross, Bernard
• Other Authors: STANFORD RESEARCH INST MENLO PARK CA NAVAL WARFARE RESEARCH CENTER
• Format: Text
• Language: English
• Published: 1965
• Subjects: Physical and Dynamic Oceanography; Snow; Ice and Permafrost; Undersea and Antisubmarine Warfare; *ICE; PROJECTILES; IMPACT TESTS; TOUGHNESS; ICE ISLANDS; ARCTIC REGIONS; OCEANOGRAPHY; FREE FALL MODELS; WARFARE; PENETRATION; Arctic; Ice; permafrost; Sea ice; Subarctic
• Online Access: http://www.dtic.mil/docs/citations/AD0630122; http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=AD0630122

Impact tests were made on floating ice slabs with particular attention devoted to the mechanism of penetration. The range of values investigated for the basic parameters was: impact velocity, 8 ft/sec - 21 ft/ sec; projectile mass, 4.56 lb - 5.22 lb and penetrator diameter, 5/16 in. - 1-1/ 4 in. The perforation of ice slabs made from seawater, and at approximately +17 deg F (warm sea ice) is accompanied by the ejection of a shear plug from the test slab, whereas fresh water ice slabs under similar loading conditions fracture into segments along well defined radial cleavage planes. The experiments indicate that a blunt end penetrator profile is significantly more effective in the perforation of warm sea ice than a corresponding penetrator with conical profile. In addition, the order of magnitude of the impact velocity and temperature of the ice slab are important factors that can govern the mechanism of penetration. A simple mathematical model for shear plug ejection, based upon the laws of conservation of linear momentum and mechanical energy, provides correlation between a potential energy quantity containing projectile mass and release height, and a geometric quantity containing penetrator diameter and sea ice thickness. Using these quantities, curves are presented which indicate a threshold-of-perforation boundary for the warm sea ice. Finally, recommendations are made for guiding future investigations in this problem area.