A Simplified Approach to the Analysis of the Ultimate Compressive Strength of Welded Stiffened Plates

In this paper, a method to calculate the ultimate compressive strength of welded one-sided stiffened plates simply supported along all edges is proposed. At first initial imperfections such as distortions and residual stresses due to welding are predicted by using simplified methods. Then, the collapse modes of the stiffened plate are assumed and collapse loads for each mode are calculated. Among these loads, the lowest value is selected as the ultimate strength of the plate. Collapse modes are assumed as follows ; (1) Overall buckling of the stiffened plateOverall collapse due to stiffener bending (2) Local buckling of the plate partLocal collapse of the plate partOverall collapse due to stiffener yielding (3) Local buckling of the plate partOverall collapse due to stiffener berthing (4) Local buckling of the plate partLocal collapse of the plate partOverall collapse due to stiffener tripping. The elastic large deflection analysis based on the Rayleigh-Ritz method is carried out, and plastic analysis assuming hinge lines is also carried out. Collapse load is defined as the cross point of the two analysis curves. This method enables the utimate strength to be calculated with small computing time and a good accuracy. Using the present method, characteristics of the stiffener including torsional rigidity, bending and tripping can also be clarified.