USE OF THE SCRATCH GAGE IN DETERMINING LONG TERM BENDING MOMENT TRENDS

The installation of scratch gages on the S.S. SEA-LAND McLEAN has provided a means of continually recording the total excursion of longitudinal stress from maximum tension to maximum compression in consecutive four hour intervals. A conventional system of strain gages on the McLEAN monitors and records continuous response of the vessel to longitudinal stresses induced from vertical and horizontal bending from both low frequency wave encounters and high frequency loads. The data obtained from both sources is statistically evaluated using the Weibull distribution for both short term and long term analyses. Theoretical predictions of extreme values for short periods of time (4 hours) based on root mean square stresses computed from strain gage records are made using the Rayleigh distribution. Long term predictions representing 47 days of continuous operation are made using the exponential distribution and the extreme values generated in the short term analysis. Both means of prediction are shown to agree closely with the scratch gage records, thereby establishing the scratch gage as a simple and accurate means of monitoring extreme bending stresses.

  • Corporate Authors:

    Massachusetts Institute of Technology

    Department of Ocean Engineering, 77 Massachusetts Avenue
    Cambridge, MA  United States  02139
  • Authors:
    • Spencer, J S
  • Publication Date: 1974-9

Subject/Index Terms

Filing Info

  • Accession Number: 00080025
  • Record Type: Publication
  • Source Agency: Massachusetts Institute of Technology
  • Report/Paper Numbers: MS Degree
  • Files: TRIS
  • Created Date: Jan 16 1975 12:00AM