Vibration Mitigation Using Seismic Metamaterials on Layered Soil

This paper investigates how the soil profile affects the vibration mitigation performance of seismic metamaterials in a wide frequency band (1 – 80 Hz). A 3D coupled finite element - boundary element (FE-BE) model with an efficient substructuring method is developed to analyze the vibration reduction performance of seismic metamaterials on top of a layered soil. Resonators are modeled as single degree of freedom systems on top of square concrete surface foundations. The response of uniform and graded metasurfaces on a homogeneous and layered halfspace due to harmonic point load are compared. The narrow band gap obtained for a uniform metasurface on a homogeneous halfspace is widened over a broader range of frequencies (40 – 70 Hz) using inverse metawedges. For layered soil conditions, vibration mitigation in a wide frequency band still emerges using metawedges. Their efficiency, however, is reduced.