The change in volume of a pressure vessel subjected to hydrostatic load is usually not a vital design parameter but may be a useful means to evaluate structural behavior. To investigate this possibility, internal and external tests were conducted on a variety of vessels ranging from gas storage cylinders to small submarines. When subordinated by strain gauge data and dimension checks, the volume change versus pressure data seems to provide a fundamental measure of structural behavior. Plotted in a curve analogous to a stress-strain curve for laboratory material tests, the data provide a signature which uniquely defines the behavior of a pressure vessel and affords new insights into that behavior. The bends observed in these test curves reveal the transitions from elastic to plastic behavior, phenomena previously difficult to detect and measure in fabricated structures. The changes in slope are used in establishing limits of elastic usefulness and in providing feedbacks to design about critical stresses and locations. Differences in structural stiffness between two vessels or the same vessel at two points in time can be measured by comparing data from two pressure tests. It is suggested that the change in slope at the bend marking the transition from elastic to plastic behavior not only measures the stress concentration but the amount of material being plastically deformed. Continuing work in this project seeks to explore the problems of fracture, fatigue and mechanics of material microstructure using the volumetric technique for pressure vessel evaluation.

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    Marine Technology Society

    5565 Sterrett Place, Suite 108
    Columbia, MD  United States  21044
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  • Publication Date: 1971-9

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  • Accession Number: 00028766
  • Record Type: Publication
  • Source Agency: United States Merchant Marine Academy
  • Files: TRIS
  • Created Date: Mar 28 1973 12:00AM