Vessel behavior in extreme situations in waves - integration in the new generation on-board intelligent system

The issues of modeling vessel behavior in general and in particular, in critical situations in waves, have been the subject of discussions at international conferences on the safety of navigation for many years. It is in the study of particular cases, confirmed by practice, that critical situations of a bifurcation nature appear (which the designers of ships, especially of large displacement, do not even suspect). The paper considers modeling of stability in waves on the data of tests of self-propelled radiocontrolled models in natural waves, carried out in the San Francisco Bay. Three typical rollover cases have been identified: complete loss of stability, resonance modes, and broaching. Of practical interest in interpreting the behavior of a vessel are the features of roll and overturning with a complete loss of stability and a given level of unsteady external disturbances. The analysis of the mathematical model of interaction has made it possible to establish some general patterns of change in the process of dynamic inclination and capsizing of the vessel with a complete loss of stability, as well as the characteristics of evolutionary dynamics when building a model of interaction. Characteristics of the features of the presented extreme situations are given together with the criterial basis for their normalization. It has been found that pitching under conditions of parametric resonance occurs in a mode close to the main resonance. Therefore, the pitching amplitude under intense external disturbances can also reach significant values exceeding the permissible trim angles. As a result of the analysis, the requirements for the safety of the vessel in the "broaching" mode have been formulated. These requirements are determined by the physical laws of the ship's roll and capsizing, established on the basis of experimental studies. The analysis of the dynamics of the vessel in the "broaching" mode revealed a catastrophic situation arising in the case of a ship leaving the "capture" mode and falling into a "potential hole", into a state of complete loss of stability.

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