Structural Optimization of Grid Shells: Design Parameters and Combined Strategies

The optimization of structures is a tricky process that involves strategies and mathematical algorithms in which the design parameters—introduced in terms of variables, constraint conditions, optimization functions, penalty conditions, and so forth—play very important roles. Their selection and introduction in the optimization process could influence the characteristics and the level of optimization of the derived solutions. This paper describes the roles of design parameters used in different optimization strategies. Moreover, an efficient optimization approach, which combines form-finding (FF), sizing-optimization (SO), and topologic-optimization (TO) strategies in a multilevel process for which design variables and constraint conditions are opportunely selected, is proposed. Numerical analyses referring to some canopy case studies derived from the current literature are also presented in the paper. The comparisons among optimization approaches, featuring FF, SO, and TO optimization strategies performed singularly or in combination throughout a simple sequence of phases, emphasize the effectiveness of the proposed approach for obtaining light structural solutions for grid shells.