| This study develops a systematic optimization design framework for the fiber reinforced polymer rectangular or square web core bridge deck systems. The proposed scheme includes two simplified analysis methods to study the bending behavior of sandwich structures and an optimization design procedure to perform optimal search of the structural geometrical parameters, sandwich configuration parameters, and material architecture simultaneously. The simplified methods consist of two stages. First, based on the classical laminated theory, an analytical homogenization method is proposed to smear a sandwich structure to a transformed plate. Second, a ritz-based discretization solution and a semi-analytical spline finite strip approach are developed to study the equivalent orthotropic plate behavior. The numerical studies show that excellent convergence rate and computational accuracy are achieved for these simplified analysis methods. The optimization design procedure is a genetic algorithm-based method devised to perform global optimal search for the mixed continuous and discrete design parameters. A novel data structure—mixed-floating-integer-array—is proposed for the representation in a one-gene-one-variable format. Consequently, specific genetic operators are tailored to accommodate the non-standard data structure and to perform evolutionary search in parallel. Based on a devised penalty function approach, a problem-independent scheme which does not require any penalty parameter is developed to handle design constraints. Several genetic global searching and local fine tuning schemes are investigated in the design procedure to remove the inherent difficulties often encountered when performing local searches for numerical applications. Several examples are demonstrated in this study, which clearly show the robustness and stability of the proposed optimization procedure. The resulting design procedures provide an effective optimal design framework for the preliminary design stage for sandwich FRP deck systems before performing detailed finite element analysis. |
