Structural Safety Assessment Based on 3D Nonlinear Wave Loads

摘要

The ship motions and wave loads based on 3D linear potential theory are very useful to evaluate structural safety of Tanker or Bulk Carrier of which hull shape over mean water line does not vary significantly but keep almost same shape. However, this linear theory is not valid for container ships which have very large bow and stern flare angle in order to carry more containers. The effect of geometrical nonlinearity due to large flare angle gets more and more important for current very large or ultra large container ships because the depth and draft keeps almost same due to limited depth of harbors, while the breadth gets larger and larger. Therefore, 3D Nonlinear Ship motion and Wave Loads are essential to calculate nonlinear dynamic loads for structural safety evaluation of container ships. In this paper, the theoretical background of 3D Nonlinear ship motion and wave loads is introduced and the verification of the code is carried out through model test. Also, the structural evaluation results for 6,500 TEU Container Carrier are shown based on both of 3D linear theory and nonlinear theory and the effect of 3D Nonlinear effect on ship structure are summarized especially in the view of hull girder strength.