Local buckling curves for the design of FRP profiles

Local buckling in FRP profiles is analyzed. Some experimental results in compression and bending, where local buckling of the flanges in compression occurred, are described and the critical stresses are summarized. A numerical model by the finite element method (FEM) is introduced and validated by comparison of the numerical results with the experimental ones. This finite element model is applied for a wide parametric analysis in order to individuate a buckling curve for the local buckling of the flange. An analytical expression of the buckling curve is developed, taking into consideration the orthotropy of the material, in which the restraint action of the web on the flange is explicitly introduced as a function of the geometrical and mechanical data of the section sub-components. The reliability of the proposed curve as a design tool is confirmed by comparison with the experimental results.