Multiple degree of freedom global analysis of transient ship rolling motion Conference Paper uri icon

abstract

  • Ship rolling motion is strongly coupled to sway and yaw and less strongly coupled to heave, pitch and possibly even surge motion. Ship capsizing is a very large amplitude global phenomenon (Falzarano, et al., 1992). In order to accurately predict the onset of ship capsizing, one must understand the multiple degree of freedom global system behavior; such an understanding will allow an accurate assessment of the limits of applicability of approximate lower degree of freedom physical models in replicating the more accurate system behavior. To date, most global dynamical systems analysis have been limited to single degree of freedom modelling (Wiggins, 1990). Few analytical studies have involved more than two degrees of freedom and many of these have dealt with solely the steady-state behavior. Most higher degree of freedom studies have involved solely simulation; however simulation studies are limited to a finite number of initial conditions and the possibility of encountering critical behavior is extremely low. In lieu of simulating ad infinitum, in this work, we choose to directly study the critical global system behavior. This direct approach involves determining the boundary of the safe basin of attraction or the set of initial conditions leading to bounded motion (Falzarano, 1990). The advantage of this approach versus the simulation approach is that prediction based upon dynamic systems analysis can be made. A minimum number of cases can then be simulated in order to verify and refine predictions based upon approximate dynamical system models. Due to the critical nature of the roll motion, and the importance of the sway-roll coupling relative to the sway-yaw or roll-yaw coupling, in this work we study solely the roll coupled to the sway motion and neglect the yaw motion.

published proceedings

  • American Society of Mechanical Engineers, Dynamic Systems and Control Division (Publication) DSC

author list (cited authors)

  • Falzarano, J., & Zhang, F.

complete list of authors

  • Falzarano, J||Zhang, F

publication date

  • December 1993