Fig. 1 Cross-sectional view of the left half of a box-shaped model.
Fig. 2 (a) Deck widths of the model and (b) vertical bending stiffness EI at each square station.
Fig. 4 Pictures (a, b) and schematic cross-sectional view (c) of the hydro-structural container ship model. (a) side view, (b) inside the hull. The location of the attached strain gauges are indicated in (c).
Fig. 5 Results of the three-point bending test and torsion test. (a) Correlation between vertical bending strains ∊v and vertical bending moments, (b) correlation between deflection δz and vertical bending moment, and (c) correlation between torsional strain ∊T and torsional moment. BT: beam theory, FE: FE analysis.
Fig. 6 FE analysis for a vertical bending test of a urethane plate with an FBG strain gauge. (a) Schematics of the cantilevered plate, and (b) FE analysis. Location of the FBG gauge is indicated by a red ellipse. The colors indicate the magnitude of normal stress; red: large, blue: small.
Fig. 7 Time series obtained from the decay tests. (a) Vertical bending moment and (b) torsional moment.
Fig. 8 Vertical bending and torsional moments measured in the towing experiment in the regular wave. (a) Time series of the vertical bending moment, (b) frequency spectrum of the vertical bending moment, (c) time series of the torsional moment, and (d) frequency spectrum of the torsional moment.
Fig. 9 Wave elevation, ship motions, and vertical acceleration at FP measured in the towing experiment in the freak wave.
Fig. 10 Vertical bending and torsional moments measured in the towing experiment in the freak wave. (a) Time series of the vertical bending moment, (b) frequency spectrum of the vertical bending moment, (c) time series of the torsional moment, and (d) frequency spectrum of the torsional moment. The lowest natural frequencies are indicated by arrows.
Fig. 3 Vibration-mode analysis with FE models. (a) 1st torsional mode, (b) 1st vertical bending mode.
Table 1 Principal dimensions and quantities related to the midship section. α is the model scale.
Table 2 Designed values related to stiffness at the midship section.
Table 3 Comparison of the wet natural frequencies. Unit: Hz
Supported by : KAKENHI
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