Recent studies have revealed that plates stiffened by closed-section ribs can be designed to have greater strength. Thus, this study is about the increasing effect on local plate buckling strength of isotropic plates when longitudinally stiffened with closed-section ribs, which is mainly due to the rotational restraint of the closed-section ribs. The effects on buckling strengths of the stiffened plates are examined by numerical analyses. Three-dimensional finite element models were obtained using a general structural analysis program ABAQUS and a series of eigenvalue analyses were conducted. Through this study, the increasing effect on the local buckling strength due to the rotational stiffness is numerically verified. From the parametric studies, there is an obvious tendency that the local buckling strength of the stiffened plate would converge to the buckling strength of plate with fixed boundary condition. The findings of this study would contribute in improving the optimum design of longitudinally stiffened isotropic plates.

This study is about the basic design technology to radically increase the structural stability of structural shell or tube, which are utilized in a variety of large structures like aircrafts, plant, bridges and buildings. Recent studies have revealed that the plates stiffened by closed-sections ribs can be designed to have greater strength as well as the reduction of used number of stiffeners. Then, the analytical models were selected based on the huge steel tube design and the finite element modeling has been conducted using the ABAQUS. Through this study, the elastic buckling strengths are compared with the flat plate buckling stress and the improved effect in the local buckling strength due to the closed-section ribs are numerically verified.