Hydroelasticity refers to resonant vibratory response of the flexible ship. Especially, whipping phenomenon is the high frequency vibrations of the ships caused by slamming impact. It is necessary to identify how much the vertical bending moment (VBM) was increased due to whipping phenomenon for reliable structural design of ships. This paper is related to hydro-elastic effect on structural design considering the hydroelastic response based on the segmented model test. To derive the whipping effect to cover hydroelastic response, Equivalent Design Sea state (EDS) approach and Equivalent Design Wave (EDW) approach were applied. Also a direct calculation approach is applied with hydro-structure interaction tools (WISH-FLEX/SNU) to compare the result of model test with analysis. Segmented model test was conducted with VLOC at Hyundai Maritime Research Institute (HMRI) towing tank. Whipping effect was evaluated with measured VBM results based on EDS and EDW approach. In EDS approach, several statistical post processing methods were used to evaluate the probable maximum values. Each result of statistical process was compared. Test results of EDS and EDW approach were compared. And the calculation was conducted with hydro-structure interaction tools under same conditions as segmented model test. Finally, comparisons between the result of model test and analysis were made. These results of hydroelastic effect are applied to structural design.
Recently, the size and speed of ships are increasing for economic reasons. With this trend, the frequency of occurrence of a hydroelastic response increased and the structural safety of ships is threatened. To improve the understanding on a hydroelasticity, considerable research efforts(such as full scale measurement, model test, numerical analysis) have been devoting.
Hydroelasticity refers to resonant vibratory response of the flexible ship such as springing phenomenon and whipping phenomenon. The springing is the steady state resonant vibration and the whipping is the transient high frequency vibration excited by slamming impact. Especially, whipping phenomenon is the cause for increasing the Vertical Bending Moment(VBM) which is related with an ultimate strength. The ultimate strength assessment is important in structural design of ships and is conducted before the ship is built for reliable structural design of ships. For ultimate strength assessment, the rule VBM suggested by classification societies is used as design VBM. But this design VBM doesn't include the whipping effect and if the whipping effect is considered, the design VBM which is used for the ultimate strength assessment will increase.
