Bandgap design of three-phase phononic crystal by topological optimization

Material topologies in phononic crystals take the key role in wave controlling. A genetic algorithm with a plane wave expansion method was adopted to optimize the three-phase phononic crystal for a larger relative band gap in both out-of-plane and in-plane wave modes. Fourier displacement property was used to calculate the structure function in the plane wave expansion. The mutation and crossover rates were calculated based on the adaptive GA method. Results indicate that the volume fraction and the symmetry are two key factors for the design of topological configurations. The relations between the key factors and the different topologies are correlated. (C) 2019 Elsevier B.V. All rights reserved.