Local buckling of composite fiber-reinforced plastic wide-flange sections

An explicit elastic stability analysis for local buckling of fiber-reinforced plastic (FRP) structural shapes is presented. Flange of pultruded FRP wide-flange sections is modeled as a discrete panel with elastic restraint at one unloaded edge and free at the other unloaded edge [restrained-free (RF) condition] and subjected to uniform distributed axial in-plane force along simply supported loaded edges. By considering a linear combination of simply supported-free and clamped-free boundary displacement fields as an interpolation function of the RF buckling, a variational formulation of the Ritz method is used to establish an eigenvalue problem, and a flange critical local buckling coefficient is determined. An explicit solution is obtained for local compressive buckling strength of orthotropic panels with the RF condition and is expressed in term of the coefficient of elastic restraint based on the flexibility of flange-web connection. The explicit predictions are in good agreements with experimental data. exact transcendental solutions, and finite-element analyses for local buckling of FRP wide-flange columns. The formulation developed in this paper is the first attempt in the literature for explicit buckling analysis of orthotropic plates with RF condition and can facilitate the local buckling analysis and design of open FRP structural profiles (e.g., I and channel shapes).