A gradient radial seismic metamaterial designed using the PSO algorithm

This study proposes a gradient radial seismic metamaterial that integrates typical engineering core geometries with particle swarm optimization (PSO) algorithm and placement optimization to realize low-frequency, broadband surface-wave attenuation in compact footprints. Under an equal-area constraint and a band-diagram objective focused on the first two bands, the T-shaped unit emerges as the most effective core, and a front-rear graded assembly superposes Bragg-scale gaps to span 5-35 Hz, aligning with the dominant frequencies of destructive surface waves. Cylindrical-coordinate finite-element dispersion analysis, 3D frequency-domain response spectra, and time-domain excitation with the 1984 Bishop record collectively verify marked reductions in stress, displacement, and peak acceleration within the target frequency, confirming engineering feasibility. The approach addresses scalability and material-use constraints while lowering onset frequency and widening the primary band gap, offering a practical pathway for building-level seismic shielding.