ABSTRACT
The design of cold formed-tubular steel-members can be considered as a multi-dimensional nonlinear optimization problem with only a few design variables, namely the coordinates of the crosssection, but with a large set of constraints, arising from fabrication, structural limitations and stress/strain and combined stability requirements.
The general formulation of this problem is introduced and typical solutions are presented. For thin-walled cross sections with more than one cell, the number of longitudinal wedls contributes substantially to the total cost and has to be considered in an optimal layout of the structure. Laser-welding allows new types of cross sections in a great variaty of structural and mechanical applications. As an example, the optimal layout of a board for scaffolding systems is presented. The thin-walled steel board has a cross section of three cells and is cold rolled and partly laser-welded. The shape of the cross section and the cost of fabrication are optimized. The underlying principles can be generalized for a wide range of applications are introduced in this paper. Analytical results and fabrication problems are presented.
