STATISTICAL ANALYSIS OF NONLINEAR RESPONSE OF MOORED VESSEL IN RANDOM SEAS - NON-NORMALITY OF SPRINGING RESPONSE OF TLP
This paper presents a statistical analyses for the second-order responses of a tension-leg platform (TLP). Second-order responses of moored vessels in random seas include two kinds of elements: difference-frequency response and sum-frequency response. Difference-frequency response leads to slow drift oscillation, sum- frequency response is generally eliminated for an analysis of slack mooring. In the heaving-motion of a TLP, the sum-frequency is large because of its high natural frequency and this leads to springing response. The non-normality of two kinds of responses are investigated and compared for surging, heaving and pitching modes. The main results are: 1) sum-frequency response of exciting force is a little larger than the difference frequency response, both of them have a large non-normality; 2) sum-frequency response of heaving and pitching motions are much larger than difference, and surging shows the opposite results, these three large responses behave similarly to normal distribution; 3) Gamma-distribution approximation and DVI method can be applied to sum-frequency response; and 4) non-normality increases and standard deviation becomes small as damping increases.
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Supplemental Notes:
- J Soc Naval Arch Japan, v 178, Dec 1995, p 237 [7 p, 9 ref, 2 tab, 9 fig]
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Authors:
- Takase, S
- Kato, S
- Teng, B
- Publication Date: 1995
Language
- Japanese
Subject/Index Terms
- TRT Terms: Moored structures; Statistical analysis; Tension
- Old TRIS Terms: Random seas; Springing; Tension leg platforms
- Subject Areas: Bridges and other structures; Data and Information Technology; Marine Transportation;
Filing Info
- Accession Number: 00728031
- Record Type: Publication
- Source Agency: British Maritime Technology
- Files: TRIS
- Created Date: Nov 4 1996 12:00AM