Stability Analysis Of Ship Structures Under In-plane Loading

Stiffened plate and grillage have been widely and commonly appllied in ship structures. The buckling strength of ship structure has been paid more and more attention little by little, with the trend of the development of the ship, high-rate and lightness. The stability of ship structure, as one of the most important research objects in the design of ship structure, has been highly concerned by mechanic researchers. The compressive buckling strength of stiffened plate and grillage has become more and more interesting and attractive for designers, because of its status that is one of the main parts of ship structures, upper deck and bottom structure, and its effects which is relevant to the gross longitudinall strength of ship structure. Therefore, the research and discussion to the stability of stiffened plate and grillage are valuable for correctedly mastering the safety, economy and enough strength space of ship structures.After summarizing the results of former researchers, some analyses are separately performed for all impossible buckling modes of stiffened plate and grillage structure. First of all, the thesis emphasizedly analysized the local buckling strength of stiffened panel with elastically restrained boundary and systemedly discussed the local unstability of stiffened panel subjected to uniaxial and biaxial compression, with the boundary conditions, including four-sides simply supported, a set of sides simply supported and another one set clamped, elastically restrained and four-sides clamped. Secondly, the thesis mainly discussed the tripping buckling strength of the Flat bar and Tee bar, considering the stiffener-plate interaction, and comparing with other tripping formulas. Thirdly, the thesis introduces the minimum lateral rigidity and the minimum longitudinall rigidity of the stiffened plate, which are used to separately judge whether the grillage and the stiffened plate are stable, and specially introduces the calculation of the slender stiffened plate and flat bar plate. Finally, on the basis of the energy theory, the thesis derived discrete beam formula and orthotropic plate formula, which can calculate the buckling strength of the grillage with the symmetry and unsymmetry boundary conditions. During thediscussion to the local buckling of the panel and stiffener and the overall buckling of the stiffened plate and grillage, we drawed out valuable conclusions, which can be used well in design and calculation, by comparing with the experienced formulas, the test data and FEM results, using FORTRAN program.