Shape Grammar of steel cold-formed sections based on manufacturing rules

This paper formalizes the domain of all and only manufacturable open cold-formed steel (CFS) profiles aimed at improving their strength capability in the development of new products. A Genetic Algorithm is applied over this domain to get a set of best solutions from structural and constructive viewpoints. A basic review is carried out with regard to (i) Shape Grammar, (ii) Finite Strip Method-based elastic buckling analysis, (iii) Direct Strength Method-based structural strength computation and (iv) modified procedure of the Non-dominated Sorting Genetic Algorithm. CFS-manufacturing is defined as a language and its general grammar is presented. This grammar-based model responds to requisites of descriptive power, simplicity of implementation, and customization to specific needs. The CFS grammar has been implemented using scripting languages available in pre-existing CAD and CAE applications. Implementation includes generation, visualization, analysis and improvement capabilities. Results show that innovative shapes with improved strength could be generated from the finite set of allowable manufacturing grammar rules encoded by the grammar.