Research On Simulation Of Ship Maneuvering-tossing Coupling Motion With Six Degrees Of Freedom In Waves

When a navigating ship is maneuvered in the sea, tossing motion always exists with maneuvering motion, but scientists research on maneuvering motion and tossing motion separately all the while, and the result can not well show actual motion state of ship navigating in the sea. The paper researches on simulation technology of ship coupling motion between maneuvering and tossing, in order to simulate and reflect the actual motion of ship navigating in sea.On the basis of ship dynamics theory, under the thought of ship maneuvering motion separate modeling, considered hydrodynamic nonlinear and coupling effect of rolling, pitching, heaving and yawing, simplified hydrodynamic expression, built the mathematical model for ship maneuvering and tossing coupling motion with 6 degrees of freedom in waves.Based on the Froude-Krylov hypothesis, ship is regard as a box, a math model of 6 degrees of freedom main interference force and excursion force in regular waves were present, which were extend to irregular wave force.Interference wave force, excursion wave force, propeller thrust and rudder force were regarded as a part of external forces to add to the ship motion model respectively, an real-time simulation system for a ship coupling motion between maneuvering and tossing with 6 degrees of freedom as rudder operated in waves was developed. After calculating in different rudder angles, wave heights and wave encounter angles, some example ship's turning track, rolling, pitching, heaving motion, and wave force time history curves were gained. The result matches foreign country designing data, which validates that the 6 degrees of freedom motion and wave force mathematical models is rational, the simulation system software is credible, which have engineering practice value.