Evaluating the influence of geometric distortions to the buckling capacity of stiffened panels

摘要

This study presents an effort to clarify the effects of initial geometric distortions to the buckling capacity of stiffened panels through numerical experimentation. Four types of imperfections have been considered, that is local (plate, web and stiffener) and global distortion types (column-like). These discrete types were considered as the factors that tend to affect the buckling capacity of the adopted finite element model. Statistical techniques of Design Of Experiments have been applied. A One Factor At a Time analysis along with a full factorial analysis have been performed for screening purposes, and the significant main and interaction effects have been evaluated. The Response Surface Method was finally employed so as to verify and narrow down the number of significant factors. From the four distortion types examined and for the particular involved collapse modes in the evaluated geometries, it was concluded that when the stiffened panel involves global distortion such that maximum global bending stress develops at the plate, then only local plate and web distortions are significant, while stiffener and global distortion may be neglected from the analysis. On the other hand, when global distortion maximizes the global bending stress at the stiffener top, then local web and this particular global distortion type have to be included.