CHAOTIC ROLL MOTION AND CAPSIZE OF SHIPS UNDER PERIODIC EXCITATION WITH RANDOM NOISE

A stochastic analysis procedure is developed to examine the properties of chaotic roll motion and the capsize of ships subjected to periodic excitation with a random noise disturbance. To take into account the presence of randomness in the excitation and the response, a generalized Melnikov method is developed to provide an upper bound on the domain of the potential chaotic roll motion. The associated Fokker-Planck equation governing the evolution of the probability density function (PDF) of the roll motion is derived and numerically solved by the path integral solution procedure to obtain joint probability density functions (JPDFs) in state space. A chaotic response can be found in two regions (near the homcolinic and heteroclinic orbits). The global behaviour of the roll motion can be depicted by the JPDF. It is found that the presence of noise enlarges the boundary of the chaotic domains and bridges coexisting attracting basins in the local regimes. The attracting domain of capsize is of the greatest strength. The probability of capsize is considered in this paper as an extreme excursion problem with the time-averaged PDF as an invariant measure. With this measure, the heteroclinic region is identified as an 'unsafe' regime. Numerical results indicate that, under the presence of noise, all roll motion trajectories of a ship that visit the regime near the heteroclinic orbit will eventually lead to capsize.

• Supplemental Notes:
  • Applied Ocean Res, v 17 n 3, June 1995, p 185 [20 p, 30 ref, 15 fig]
• Authors:
  • Lin, H
  • Yim, Solomon C
• Publication Date: 1995

Language

• English

Subject/Index Terms

• TRT Terms: Capsizing; Noise; Rolling; Stochastic processes
• Subject Areas: Data and Information Technology; Environment; Marine Transportation;

Filing Info

• Accession Number: 00728009
• Record Type: Publication
• Source Agency: British Maritime Technology
• Files: TRIS
• Created Date: Nov 4 1996 12:00AM