Evaluation of Hull Vibratory (Springing) Response of Great Lakes Ore Carrier M/V STEWART J. CORT
DAVID W TAYLOR NAVAL SHIP RESEARCH AND DEVELOPMENT CENTER BETHESDA MD STRUCTURES DEPT
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The hull vibration springing of the Great Lakes ore carrier STEWART J. CORT was evaluated on the basis of accelerometer and strain gage data collected during a regular round trip voyage between Burns Harbor, Indiana, and Taconite Harbor, Minnesota, in August 1972. Springing was recorded when, in the loaded condition, CORT encountered 4- to 6-ft seas, 60 deg to the bow in Lake Superior. The maximum first mode deflection profile and midship bending stress were determined from a direct analysis of this springing record. A spectrum analysis of the same record produced flexural frequencies of vibration for the first three vertical modes and what appeared to be the first horizontal mode, rms deflection profiles for the first three vertical modes, and the first mode rms midship bending stress. An important finding of the investigation was that the springing deflections of the CORT involved larger contributions than expected from the second flexural mode of vibration.
- Marine Engineering