SHIP VIBRATION PREDICTION METHODS AND EVALUATION OF INFLUENCE OF HULL STIFFNESS VARIATION ON VIBRATORY RESPONSE.
Research is conducted to obtain a greater understanding of induced hull vibrations and, more specifically, to define the role of hull stiffness in such phenomena. Available methods for the prediction of vibratory response to propeller, slam and wave excitations are evaluated. The work scope is limited essentially to the vertical vibration of the main hull. Parametric analyses are presented which include the calculations of the propeller, slam- and wave-induced vibrations of three ships with their hull stiffness varying from 40 percent below to 40 percent above the as-built stiffness. The three ships are a 249,300 DWT tank ship, the Great Lakes ore carrier "STR. EDWARD L. RYERSON" and the 544 ft. general cargo ship "S. S. MICHIGAN." Design trends are developed with respect to characteristics that influence ship stiffness and vibratory response. Propeller-induced main hull vibrations for all three ships do not appear to be effected by variations in hull stiffness. Slam-induced vibrations seem to increase and decrease as stiffness increases and decreases. The tank ship and the Great Lakes ore carrier appear to be prone to wave-induced vibration, and increased hull stiffness has a beneficial effect on limiting the response. Further research is required which would lead to engineering methods for the estimation of propeller excitation forces and slam loads which can be used to predict vibration during the design stages. Literature on wave-induced vibration is limited and the subject deserves significant research effort. Particular attention should be paid to the effects of forebody and afterbody shapes and damping.
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Rosenblatt (M) and Son, Incorporated350 Broadway
New York, NY USA 10013
- Kline, R G
- Daidola, J C
- Publication Date: 1974-6
- Features: References;
- Pagination: 191 p.
- TRT Terms: Hulls; Measurement; Vibration
- Identifier Terms: Ship Structure Committee
- Old TRIS Terms: Hull stiffness; Hull vibration; Vibration measurement; Wave excited vibration
- Subject Areas: Design; Marine Transportation; Materials;
- Accession Number: 00095188
- Record Type: Publication
- Source Agency: Ship Structure Committee
- ISBN: Task 20221 SR-214
- Report/Paper Numbers: SSC-249 Final Rpt.
- Contract Numbers: N00027-73-C-5206
- Files: TRIS
- Created Date: May 29 1975 12:00AM