Ringing and double frequency response of a tri-pod
The dynamic behavior of a tri-pod steel jacket installed in 65 m water depth in the North Sea has been investigated. The analysis method is a time-domain simulation of the platform exposed to irregular sea. Similar to monotower platforms the so-called ringing phenomenon caused by higher order harmonics in the wave loading is detected. Further, the analysis discovered another dynamic feature, double frequency response, caused by the interaction between the spatial distribution of the waveload and the shape of first vibrational mode. The dynamic response showed that the top of the platform vibrates notably more in first mode than found by a quasi static analysis with incorporation of standard dynamic amplification factors, however, the resulting extreme stress level and accumulated fatigue damage is found quite similar and the consequences to human comfort small. The basis for this finding is the fact that first mode only contributes very little to the stress level in critical points.
- OSTI ID:
- 449696
- Report Number(s):
- CONF-9606279-; ISBN 0-7918-1490-4; TRN: IM9714%%253
- Resource Relation:
- Conference: 14. international conference on offshore mechanics arctic engineering (OMAE), Florence (Italy), 16-20 Jun 1996; Other Information: PBD: 1996; Related Information: Is Part Of Proceedings of the 15. international conference on offshore mechanics and arctic engineering -- OMAE 1996. Volume 1, Part A: Offshore technology; Chakrabarti, S.K. [ed.] [Chicago Bridge and Iron Technical Services Co., Plainfield, IL (United States)]; Pontes, M.T. [ed.] [Inst. Nacional de Engenharia e Tecnologia Industrial, Lisbon (Portugal)]; Maeda, Hisaaki [ed.] [Univ. of Tokyo (Japan)]; Falzarano, J. [ed.] [Univ. of New Orleans, LA (United States)]; Schofield, P. [ed.] [W.S. Atkins, Surrey (United Kingdom)]; Morrison, D. [ed.] [Shell E and P Technology Co., Houston, TX (United States)]; PB: 530 p.
- Country of Publication:
- United States
- Language:
- English
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