Fully coupled seakeeping, slamming, and whipping calculations

This paper presents a methodology to solve the seakeeping, slamming, and whipping problems coupled within a single calculation. The coupled problem is solved within a partly non-linear time domain seakeeping program. The elastic modes used in this hydroelastic problem can be calculated using a beam model or full three-dimensional (3D) finite element model of the ship structure. The slamming loading is calculated by a two-dimensional (2D) method. The main focus of this paper is the creation of an accurate and consistent coupling between the 3D seakeeping program and the 2D slamming calculation. Differences in timescale and integration methods make this coupling complex. A large container ship is used to illustrate the application of the presented methodology. The contribution of the non-linearities and the whipping response to the expected maximum bending moment and fatigue damage of this ship for a full-wave scatter diagram is calculated. The results show that the slamming-induced whipping response has a significant contribution to both the ultimate bending moment and the fatigue loading of the ship.