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.

  • Supplemental Notes:
    • J Soc Naval Arch Japan, v 178, Dec 1995, p 237 [7 p, 9 ref, 2 tab, 9 fig]
  • Authors:
    • Takase, S
    • Kato, S
    • Teng, B
  • Publication Date: 1995

Language

  • Japanese

Subject/Index Terms

Filing Info

  • Accession Number: 00728031
  • Record Type: Publication
  • Source Agency: British Maritime Technology
  • Files: TRIS
  • Created Date: Nov 4 1996 12:00AM