The Equivalent Value of the Linearized Method for the Ship Motion in Irregular Sea Waves

불규칙(不規則) 해양파(海洋波)에 대(對)한 선체운동(船體運動)의 등가선형화(等價線型化) 방법(方法)에 관(關)하여

The characters of linear response of ship among irregular waves were researched. But nonlinear characters of ship motion in irregular waves have not been considered. Then the author showed a method to linearize nonlinearity of damping coefficient of ship by making statistically equivalent linear theory and get equivalent gain K from the condition that the difference of variance between linear response and approximate response is minimum and show that the results of correlogram and spectrum, obtained from this method, for model 700 GT Ferry boat agree with the actual response. The author pays a particular attention not to the nonlinear element but to nonlinear system itself.