Buckling Behavior of Axially Compressed Welded Flat Panel Stiffened Plates Utilizing High-Strength Steel

The beneficial strength properties of high-strength steel (HSS) enable a reduction in the cross-sectional dimensions of flat panel stiffened plates. However, this leads to increased challenges related to buckling under axial compression. This research examined the buckling behavior of welded flat panel stiffened plates under axial compression made from HSS through a combination of experimental tests and numerical simulations. The primary parameters studied included steel strength, the width-to-thickness ratio of the plates, slenderness ratio, residual stress, and initial geometric imperfections. The main failure modes were analyzed. Residual stresses were found to reduce the ultimate bearing capacity of members with moderate slenderness ratios and relatively small width-to-thickness ratios by as much as 8%, compared with the case without residual stresses. The impact of initial geometric imperfections becomes more pronounced as the member slenderness ratio increases, but decreases with increasing plate width-to-thickness ratio. The utilization of steel strength decreases with increased steel strength, plate width-to-thickness ratios, and member slenderness ratios. Furthermore, the calculation methods for ultimate bearing capacities prescribed by current design standards are deemed unsafe under certain conditions, overestimating capacities by as much as 41% and 32%. Consequently, a direct strength method (DSM)-based approach is proposed, which provides reliable assessments for flat panel stiffened plates constructed from steel with a yield strength of 420–960 MPa.