Shaping of open cross section of the thin-walled beam with flat web and multiplate flange

The subject of the analysis is a thin-walled prismatic beam with flat web and multiplate flange. The beam is loaded at both ends and submitted to pure bending. Open cross section of the beam is described by five dimensionless parameters controlling its shape. Basic values of cross section area resulting from classical theory of beam bending, warping function and warping moment of inertia resulting from general theory of warping torsion have been determined. The parametric shaping of the cross section is reduced into the problem of maximization of bending moment for fixed cross section area. Constraints of the solution result from geometrical, strength, and stability conditions. Numerical analysis has been performed.