Paper title: Experimental Study of the Interaction of Corrosion Damage and Out-Of-Circularity in the Collapse of Submarine Pressure Hulls
J R MacKay and M J Smith, Defence R&D Canada Atlantic, Canada
F van Keulen and T N Bosman, Delft University of Technology, The Netherlands
The effect of corrosion damage on overall collapse strength of submarine pressure hulls was studied experimentally. Ring-stiffened cylinders were machined from aluminium tubing and loaded to collapse under external pressure. In selected specimens, some of the outer shell material was machined away in large single patches, representing general corrosion. Other specimens had many smaller patches, representing corrosion pitting from the outside of the hull, followed by grinding. Large-amplitude out-of-circularity (OOC) was introduced by mechanically deforming selected cylinders. Clusters of artificial corrosion pits were found to have approximately the same effect on collapse pressure as equal-depth general corrosion covering the same region of plating. General corrosion was found to be most severe when it was “in-phase” with OOC, since, during pressure loading, high compressive stresses resulting from corrosion were compounded by compressive bending stresses associated with OOC, and furthermore, the corrosion tended to increase the geometric imperfection itself. On the other hand, out-of-phase corrosion reduced the effect of OOC, while at the same time the thinning-associated compressive stresses were counteracted by local tensile bending stresses associated with OOC, so that strength reductions were correspondingly smaller. Overall collapse pressures for corroded specimens were reduced by, on average, 0.85% for each 1% of shell thinning. That result is based on a linear approximation of the nonlinear relationship between thinning and collapse pressure. The linear trend-line, which was used to account for the experimental scatter, is based on specimens with 13 to 27% shell thinning, and with a variety of corrosion areas and OOC amplitudes.
Transactions RINA, Vol 154, Part A3, International Journal Maritime Engineering, Jul-Sep 2012
DOI No: 10.3940/rina.ijme.2012.a3.229tn
Search and Order IJME papers
All International Journal of Maritime Engineering (IJME) papers are listed in the RINA Publications Database. You can search the database by author name and paper title. Publications may be ordered and paid for online. Other publications are also listed, some of which may be downloaded free of charge. Follow the link to Search Publications & Order.