A method for selecting macro-scale structures with axially loaded members

This paper presents a method to support the selection of lightweight large-scale structures. The method enables the ranking of alternative structural forms, whose axially loaded members can resist to either instability failure or material yield. Unlike previous approaches for concept design, this work models buckling failure to assess the interaction between the choice of a structural form and the choice of the cross-section shapes of its constituents. Shape transformers and scaling factors are introduced to characterize the structural efficiency of alternative cross-sectional shapes. Such parameters are dimensionless and enable to measure the shape efficiency without specifying the details of the cross-section geometry. The approach eases optimization at the concept design stage and it permits to assess how the selection of the member cross-sections impacts the lightweight potential of the structural topology. The model is used to construct charts for optimizing and selecting alternative forms. The method is applied in an industrial setting in order to compare three different structural concepts for a particular design application. The case study identified the potential performance of three structural forms and gave insight into the selection of the parameters that most influence structural performance.