Predictions of the Collapse Strength of Three HY-100 Steel Spherical Hulls Fabricated for the Oceanographic Research Vehicle Alvin

摘要

Out-of-roundness measurements were taken on three spherical pressure hulls which have been fabricated for ALVIN, a two-man oceanographic vehicle designed for an operating depth of 6000 ft. The results of these measurements indicated that over a critical arc length, the maximum ratio of local radius to nominal radius was 1.05. The collapse strength of the three hulls was evaluated by means of a recently developed analysis which utilizes local geometry as determined by out-of-roundness measurements. Based on critical local geometry and available stress-strain curves, the analysis indicated that the collapse depths of the hulls ranged from approximately 15,000 to 16,000 ft. A high degree of confidence is placed in the results, and the importance of accurately measuring the shape of spherical shells is emphasized. (Author)