Theoretical shape optimization of cold-formed thin-walled channel beams with drop flanges in pure bending

The paper is devoted to cold-formed thin-walled channel beams with open or closed profile of drop flanges. Geometric properties of two C-sections are described with consideration of warping functions and warping inertia moments. Optimization criterion and the dimensionless objective function as a quality measure are defined. Constraints of feasible solutions are strength, global and local buckling conditions and also geometric condition. Analytical solutions of the problems of global and local buckling for thin-walled beams are presented. Results of numerical investigation of optimization problem are compared and presented in tables and figures.