Impact wave dispersion characteristics in Bouligand-type structures

A Bouligand structure is a special class of natural phononic crystals, which enables changes in configuration to achieve effective control of wave propagation. Here, we report an analytical modeling approach to study the impact energy filtering and the regulatory configuration mechanism in such structures. First, we demonstrate that by adjusting the helicity of structures and material properties of the Bouigand-type periodic structure, the size of bandgaps can be controlled and even implemented dispersion-free states. We then establish impact wave propagation models based on the propagator matrix method, which can be analytically evaluated for gradient-layered structures. Finally, we show that Bouligand-type materials with naturally occurring pitch gradient can effectively filter the impact energy generated by stomatopods. This is of interest for future design of vibration isolation devices, stealth aircraft skin, and offshore platform support and can provide important insight into structure-property relationships of the Bouligand-type structures.