THE INTERPRETATION OF SMALL SCALE STRENGTH DATA FOR ICE

The task of either predicting the destructive force of an ice sheet or its bearing capacity is complicated by two main problems. The first is that due to the great thickness attained by natural ice sheets, huge forces are required to perform full scale tests to failure. Peyton cites the possibility of a 7 million kg. force exerted by a one meter thick ice sheet on a typical offshore structure. Experimenting at such force levels requires a great deal of effort and expense. The second problem is that the strength of an ice sheet depends on many parameters, e.g., the thickness, temperature, rate of loading, and salinity. Hence, the results of one full scale strength test on an ice sheet constitute one point on a four dimensional strength envelope. To circumvent these two problems, many investigators have sought to study the strength of ice via small scale strength tests. In particular, these tests have been performed on cylinders, small beams, rings, and discs, whose typical dimensions range from 1 to 20 cm. Unfortunately, many of these small scale results have failed to agree amongst themselves. The view expressed in this paper is that there is an inadequacy associated with the interpretation of these tests, and that this inadequacy lies in the failure to consider the effect of plastic creep and grain size. This paper is concerned with the inclusion of these two factors in the analysis of small sample results and with the investigation of their effect generated for simulated test situations. This paper presents these results, emphasizing the nature of the stress distributions that are developed, and the type of stress distribution that results in failure. The influence of plastic creep and grain size on the results of small scale strength tests on ice is also determined. This influence is used to explain and correlate the existing small scale strength data, and the various parameter dependencies. A failure criterion for individual ice crystals was developed. Finally, the increased understanding of the small scale test provides a basis for a discussion of the application of these test results to full scale ice sheets.

• Supplemental Notes:
  • Abstract of paper delivered at the First International Conference on "Port and Ocean Engineering under Arctic Conditions" held at Trondheim, Norway, August 23-30, 1971
• Corporate Authors:

  POAC Conference

  ,    
• Authors:
  • Maser, K R
• Publication Date: 1971-8-23

Subject/Index Terms

• TRT Terms: Force; Ice; Mechanical properties; Strength of materials
• Old TRIS Terms: Ice forces on structures; Ice models; Ice strength
• Subject Areas: Marine Transportation; Materials;

Filing Info

• Accession Number: 00025688
• Record Type: Publication
• Source Agency: Arctic Institute of North America
• Files: TRIS
• Created Date: Mar 28 1972 12:00AM