面内圧縮荷重を受ける連続防撓パネルの座屈・塑性崩壊挙動に関する研究

抄録

This paper describes the buckling/plastic collapse behaviour of continuous stiffened plates under thrust obtained by elastoplastic large deflection analysis using the finite element method. Flat-bar and angle-bar stiffeners are considered, and the influence of cross-sectional geometries of stiffeners, the aspect ratio and welding imperfections of stiffened plates on the buckling/plastic collapse behaviour is investigated. It has been found that: (1) The number of local buckling waves in longitudinal direction tends to be increased by the flexural-torsional rigidity of stiffeners, comparing with the simply supported plates. (2) The change in local deflection mode due to a secondary buckling is likely to take place when a local initial deflection is given in a single sinusoidal form which is different from the local buckling mode. In real ship platings, however, such a change in deflection mode does not frequently occur, since the actual initial deflection due to fillet welding is of complex form and must have the deflection component of a local buckling mode. (3) The influence of the mode of local initial deflection on the ultimate strength and post-ultimate strength behaviour of stiffened plates is small. (4) For the larger aspect ratio of the plate between stiffeners, the smaller ultimate strength is attained because of the increase of a span length and the resulting reduction of a column buckling strength. For the same reason, the load-carrying capacity after the ultimate strength decreases more rapidly. (5) The residual stress due to fillet welding significantly decreases the ultimate strength of stiffened plates. The secondary buckling more likely takes place in the presence of welding residual stress.