An Analytical Design Approach for Outstand Steel Plates in Compression

Current design approaches to determine the capacity of plates in local buckling are based on empirical equations, in particular the widely used Winter equation. In contrast, this research presents a novel analytical approach, focusing on outstand steel plates. The derivation of the method is rooted in the Föppl‐von Karman equations, which are first simplified by making a number of basic mechanical assumptions about the post‐buckling stress field. An approximate solution to the emerging differential equation is obtained, which assumes a polynomial displacement profile in the transverse direction of the plate. This solution agrees eminently well with the results of finite element simulations, both for the case of a geometrically perfect plate and a plate containing an initial imperfection. By combining the obtained post‐buckling stress profile with a failure criterion based on von Karman's effective width concept, a closed‐form strength equation for compressed outstand plates is derived, which is seen to be a sole function of the plate slenderness and a dimensionless imperfection factor. This equation agrees closely with the available experimental data.