Hydrodynamic interaction effects between VLFS and submerged plate are presented in this paper. A composite grid method has been employed to compute the interaction effects of hydrodynamic forces on VLFS with or without submerged plate.The fully nonlinear free surface flow problem, which involves the overturning and breaking waves, is solved using the finite difference method. In order to investigate the interaction effect, the fore part of VLFS has forced to heave sinusoidally with the submerged plate or not. Furthermore, the reflective wave by VLFS, which acts on the submerged plate heaving near a free surface, is considered to estimate the hydrodynamic forces. The added mass and damping forces are shown to be influenced strongly by the interation effects and are presented as a function of oscillation periods. Namely, the added mass on the whole are increased due to the interference effects between VLFS and submerged plate regardless of oscillation periods. On the other hand, the damping forces become larger at short oscillation periods because of impinging wave which came from the reflection by the other structure. The influence of added mass and damping forces means that the response amplitude of VLFS is decreasing. These results reaffirm that the effect of submerged plate on hydroelastic deflection is significant at short oscillation periods. The results obtained by the present numerical simulation are compared with those obtained by the experiments, and it shows a good agrrement.
アルミニウム合金材 JIS A5083P-O材を供試して，軸力圧縮予歪材の引張強度特性を把握した。さらに，JIS A5083P-H321材の帯板試験片による，座屈崩壊後の繰り返し大変形曲げ亀裂発生強度を把握した。得られた知見は以下のとおりである。（1）公称歪で約-50％（真歪で約-65％）までの軸力圧縮歪を与えたA5083P-O材の引張強度特性，すなわち降伏応力（0.2％耐力），引張強さおよび伸びなどを把握した。（2）A5083P-H321材に対しての，座屈崩壊後の，500_-_600cycles以下の繰り返し大変形曲げに対する亀裂発生寿命が評価可能になった。すなわち，初回曲げ圧縮後の試験片長さ方向の公称歪から推定した歪範囲と，長さ0.5ｍｍの微小亀裂発生繰り返し回数との関係式が得られた。