Experimental Investigations into Unprecedented Electro-momentum Coupling

The discovery of the Willis coupling, described as the non-local coupling of momentum and strain, exhibited by architected metamaterials has led to the theorization of further non-local coupling phenomenon, one of which is electro-momentum coupling. Electro-momentum coupling has the potential to realize electric field sensing or elastic wave generation through the bulk metamaterial structure. Electro-momentum coupling entails the coupling of the momentum of the metamaterial to its electrical properties. This coupling is facilitated through the integration of piezoelectric materials into the metamaterial, allowing for the phenomenological bridging of strains to electrical potential. This metamaterial structure must essentially combine the piezoelectric effect along with Willis coupling in order to realize the electro-momentum coupling. This type of coupling at the macroscale is unprecedented and empirically unobserved as of now. In this research, we aim to experimentally confirm the theoretical observations of recent works proposing the functionality of unidimensional stacked metamaterial structures.<br/>Primarily, this work involves the precise fabrication of metamaterials using an advanced custom designed multimaterial 3D-printing method capable of printing piezoelectric materials. This method allows for the precise tailoring of the material distribution in the metamaterial structure as required by theoretical calculations. The metamaterial consists of barium titanate (BaTiO₃), lead zirconate titanate (PVT4), and polyvinylidene fluoride (PVDF) all of which are tightly integrated into the metamaterial structure in periodic unit cells. Current experimental efforts involve the testing of a unidimensional sample and empirically observing electro-momentum coupling. These experiments involve the application of a dynamic load onto the metamaterial and measuring its transient displacement field while simultaneously measuring the unidirectional electric field distribution. Through this work, we aim to provide the first empirical observations of this coupling phenomenon.