Longitudinal and shear waves propagation in a periodic foundation with negative Poisson's ratio

The introduction of negative Poisson's ratio materials in engineering has opened new possibilities in materials science, acoustics, and civil engineering. Isotropic elastic foam with a negative Poisson's ratio of -0.7 has been produced which expands laterally when stretched, in contrast to ordinary materials. In this work, a new arrangement of seismic isolation foundation containing a unit cell of concrete - anti rubber and concrete/steel layers is proposed. The novelty lies in application of anti-rubber material as one of the three different layers periodically placed to form a periodic foundation. The auxetic material inclusion in this new arrangement broaden the no pass band of the periodic foundation compared to the earlier investigations. To demonstrate the effectiveness of this metamaterial foundation, an axially loaded column placed under three different foundations are numerically investigated. It is observed that the response of the metamaterial foundation with auxetic inclusion attenuated the elastics waves greatly compared to the foundations with rubber and traditional foundations. The results of the study could be used in developing new foundation materials for vibration attenuation for seismic waves which may cause destruction to engineering structures.