ESTIMATION OF THE SPECTRUM OF NON-LINEAR SHIP ROLLING: THE FUNCTIONAL SERIES APPROACH

The objective of the present work was to investigate the applicability of the functional series model to nonlinear ship rolling, under the assumption that the usual single-degree-of-freedom rolling equation holds. Particular emphasis was given to the development of means of estimating the spectrum of nonlinear roll. In applying the functional series to roll it was found necessary to approximate the usual quadratic damping representation by a cubic. Given this, the application was reasonably straightforward. Expressions were developed for the spectrum of roll in the form of a series carried through to terms of fifth degree. A trial evaluation of the spectrum of a previously simulated case of nonlinear rolling was made under the assumption that terms of fifth degree were negligible. The results appeared reasonable for moderate rolling at least. It appears that the functional series approach, while not the only approach to nonlinear rolling, might be developed into a practical alternative. (Author)

• Corporate Authors:

  Stevens Institute of Technology

  Davidson Laboratory, Castle Point Station
  Hoboken, NJ  United States  07030
• Authors:
  • Dalzell, J F
• Publication Date: 1976-5

Media Info

• Pagination: 56 p.

Subject/Index Terms

• TRT Terms: Damping (Engineering); Damping (Physics); Degrees of freedom; Hulls; Hydrodynamics; Mathematical prediction; Military vessels; Nonlinear programming; Nonlinear systems; Ocean currents; Ocean waves; Oscillation; Rolling; Ship motion; Simulation
• Uncontrolled Terms: Ship hulls
• Old TRIS Terms: Roll; Roll damping; Roll simulation; Sea states
• Subject Areas: Data and Information Technology; Hydraulics and Hydrology; Marine Transportation; Vehicles and Equipment;

Filing Info

• Accession Number: 00145708
• Record Type: Publication
• Source Agency: National Technical Information Service
• Report/Paper Numbers: SIT-DL-76-1894 Final Rpt.
• Contract Numbers: N00014-75-C-0278
• Files: TRIS
• Created Date: Jan 16 1977 12:00AM