Modified non-dominated sorting genetic algorithm-II for the optimal design of soil-concrete periodic plane wave barriers

This paper uses the Bloch-Floquet theory based on the modified non-dominated sorting genetic algorithm-II (NSGA-II) to investigate the optimal design of wave barriers to attenuate plane waves. The primary aim is to find the optimal design of the plane wave barriers with a wide bandgap at a low-frequency range having low construction cost. Consequently, a modification of NSGA-II has been developed and adopted to obtain the optimal arrangement of concrete within different 8 x 8, 10 x 10, and 12 x 12 grid sizes in the wave barrier unit cell by considering three objective functions as (1) maximize bandgap width (BW), (2) minimize average bandgap frequency (ABF), and (3) minimize filling ratio (FR). The Pareto fronts represent a wide range of objective functions in the problem space, making the proposed method effective for designing plane wave barriers. The performance of the optimal barriers is examined with the three-dimensional finite element (FE) simulation of the finite lattice in the frequency domain. The finite lattice results confirm the obtained bandgaps for the optimal unit cells and verify their efficacy in attenuating plane S-waves. Furthermore, the effects of the number of barriers and the barrier length are studied as two effective parameters affecting plane S-wave attenuation.

Automated summary

This paper investigates the optimal design of wave barriers using the modified non-dominated sorting genetic algorithm-II (NSGA-II) and the Bloch-Floquet theory. The aim is to find the optimal design of plane wave barriers with a wide bandgap at a low-frequency range and low construction cost. The study develops a modified NSGA-II algorithm to determine the optimal arrangement of concrete in wave barrier unit cells. The performance of the optimal barriers is examined through finite element simulation and their efficacy in attenuating plane S-waves is verified.