Broadband wave attenuation and topological transport in novel periodic pile barriers: Fid-Bau Portal

Broadband wave attenuation and topological transport in novel periodic pile barriers

Ni, Anchen / Shi, Zhifei

Highlights • The concept of topological insulator is introduced to develop new kinds of wave barriers. • Both attenuation zones and edge states are realized in the novel periodic pile barriers. • The attenuation zone and topological transport are studied based on the complex dispersion. • The numerical simulations are conducted both in frequency domain and time domain. • This novel wave barrier is with vibration mitigation and wave-guiding simultaneously.

Abstract Topological insulator (TI) has received enormous attention in recent years due to its intriguing dynamic characterizes of topologically protected wave transport and defect immunity. Besides, the elastic waves can propagate along the pre-designed interface but body, which may dramatically promote practical applications of novel devices. This work introduces the concept of TI into the design of periodic pile barriers, which is expected to realize vibration mitigation and waveguiding simultaneously. By tuning the difference of pile radius, the inversion symmetry is broken and the attenuation zone (AZ) emerges. Then, the topological phase transitions happen when pile positions are interchanged in a unit cell and the opposite valley Chern numbers (Cv) are obtained meanwhile. Based on the complex dispersion ( $k (ω)$ method) analysis of supercell, the existence of topological edge states between two types of unit cells with distinct topological phases is confirmed at first. Second, some key parameters affecting the design of periodic pile barriers is discussed comprehensively, especially the influence of soil damping on attenuation zones and edge states. Compared to the traditional real dispersion ( $ω (k)$ method), the complex dispersion can describe the propagation property and attenuation property synchronously, providing useful guidances for this novel multifunctional periodic pile barriers. Subsequently, broadband wave attenuation and topological wave transport of novel periodic pile barriers are further validated by the analysis in both frequency domain and time domain, showing high vibration reduction and transmission efficiency. This new kind of wave barriers may have great potential for both vibration mitigation and elastic wave energy harvesting.