Multi-objective optimization of two-dimensional porous phononic crystals

In this paper, we show that it is possible to design two-dimensional (2D) porous phononic crystals (PnCs) with a simultaneously maximal bandgap width (BGW) and the minimal mass through multi-objective optimization (MOOP) by using the non-dominated sorting-based genetic algorithm II. Compared with the single-objective optimization, the optimized structures from the MOOP can achieve a balance between the relative BGW and mass of PnCs. For the combined out-of-plane and in-plane wave modes, we present an optimized design with the relatively big BGW, which breaks the record value of 2D porous PnCs.