Parametric optimization of an aperiodic metastructure based on genetic algorithm

The paper presents an integrated analytical, numerical and experimental study on a kind of one-dimensional finite aperiodic metastructure, with mass-in-mass unit cells optimized for the broadband wave attenuation via genetic algorithm. The study begins with the analytic wave solution of the aperiodic structure and numerically validates the correctness of the wave solution in both frequency domain and time domain. Then, the paper outlines the optimization scheme in order to connect multiple separated narrow bandgaps into a wider continuous one, including the objective function of the wave attenuation, the design variables of inner masses and their constraints. The numerical studies show the successful broadband wave attenuation with a low vibration transmissibility in one direction and two opposite directions, respectively, based on the genetic algorithm method. The maximal attenuation bandwidth of the optimized aperiodic structure increases about 90% compared with the conventional repetitive local resonance, without any mass increase. Finally, the paper gives experimental studies of a 3D-printed lattice structure with an adjustable inner mass in each cell. The measured vibrations of the fabricated structure experimentally validate the optimized aperiodic structure with the broadband wave attenuation, as well as the effectiveness of proposed optimization method.