Topology optimization method for materials zoning of a concrete face rockfill dam

For finding a reasonable layout of the fill materials in the dam body of a concrete face rockfill dam (CFRD), a new algorithm is proposed based on continuum topology optimization. In the present approach, the materials in dam are classified into several materials with different moduli and each material has a material number (an integer) according to the value of modulus. Material with higher modulus has a bigger material number. The finite element method (FEM) is adopted to find the deformation of structure. In design domain, the material number of a finite element is considered as a design variable in optimization. Hence, zoning optimization of fill materials in a CFRD is a typical multiple material layout optimization with discrete design variables. To improve the efficiency of optimization process, a criterion is used for update of material numbers. It says that the stiffer materials are layout in the areas with higher strain energy density (SED). According to the criterion, materials for those elements with low SEDs are replaced with softer materials. The optimization is completed if all the volumes of materials reach their critical values. Two numerical examples are considered to show the feasibility and efficiency of the method. In particular, the material zoning of a CFRD is studied. The deflection of face slab of dam is less than the value reported. The result implies the present material layout is a stiffer design.   Key words: Layout optimization, concrete face rockfill dam (CFRD), multiple materials, strain energy density (SED), finite element.