CHAOTIC MOTION OF A NONLINEARLY MOORED STRUCTURE

This paper describes an experimental study of wave induced chaotic motions of a floating structure with nonlinear moorings. The structure is modeled as a rectangular box, and the moorings are represented by a nonlinear restoring force-displacement relationship corresponding to an idealized geometric nonlinearity associated with a slack mooring or a mooring with gaps. The results are presented in the form to time series, phase portraits, spectra, Poincare maps, and Lyapunov exponents. The influence of various governing parameters on the response is examined. Periodic, sub-harmonic and chaotic responses are observed for both monochromatic and bichromatic waves. In general, sub-harmonic and chaotic responses were obtained for bichromatic excitation to a greater extent than for monochromatic excitation. Transient chaotic motions have also been observed. Poincare maps of the response exhibit a distinct fractal structure under certain conditions, indicating the presence of chaotic motions. Finally, Lyapunov exponents, which provide a quantitative indication of chaotic motions, have also been computed for each time series, and are used to confirm the presence of a chaotic response.

  • Supplemental Notes:
    • ISOPE 94, 4th Intl Offshore & Polar Engng Conf; 10-15 April 1994; Osaka, Japan. Sponsored by ISOPE, USA et al. Procs. Pubs by ISOPE, ISBN 1-880653-13-3. Vol III, p 338 [8 p, 11 ref, 2 tab, 14 fig]
  • Authors:
    • Isaacson, M
    • Phadke, A
  • Publication Date: 1994

Language

  • English

Subject/Index Terms

Filing Info

  • Accession Number: 00716080
  • Record Type: Publication
  • Source Agency: British Maritime Technology
  • Files: TRIS
  • Created Date: Feb 28 1996 12:00AM