STRENGTH STUDIES OF SEA ICE - EFFECT OF LOAD RATE ON RING TENSILE STRENGTH.
Technical rept. Aug 66-Apr 67,
NAVAL CIVIL ENGINEERING LAB PORT HUENEME CALIF
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A quick, accurate method of estimating the load-carrying capacity of sea ice subjected to rapidly applied loads such as those imposed by moving aircraft and surface vehicles is needed to promote the safe and efficient use of sea ice by these forms of transportation. Tensile strength is one of the critical parameters in determining load-carrying capacity under these conditions which produce an elastic response in the sea ice. An approximate measurement of this strength can be determined by the ring-tensile-strength test of small specimens however, temperature, salinity, crystallography, and load rate affect the results of this test. Ring tensile strength is a function of loading crosshead speed and decreases as much as 91 from crosshead speeds 2.54 to 25.4 cm 1 to 10 inchesmin. A minimum crosshead speed of 50.8 cm 20 inchesmin is required to achieve true elastic failure and is approximately 30 times greater than the load rate of 0.5 kgsq. cmsec 7.11 psisec commonly used for sea-ice strength tests. Apparatus used in the past have not tested specimens at a high enough load rate to assure elastic failure. In addition to low load rates used in the past, processing sea-ice specimens has also been too slow to minimize detrimental brine drainage and temperature changes to non-in-situ conditions. Properly designed test apparatus is required to rapidly collect and process sea-ice specimens and to test them at a crosshead speed of at least 50.8 cmmin. Author
- Snow, Ice and Permafrost