Wave propagation characteristics of quasi-3D graphene origami-enabled auxetic metamaterial plates

This study presents an investigation into the elastic wave propagation of graphene origami (GO)-enabled auxetic metamaterial plates, using a quasi-three-dimensional (3D) model for the first time. It introduces an eight-parameter quasi-3D theory for the governing equations of motion of the metamaterial plates, including axial, transverse, rotational, and stretching motions through variational algebra. Material properties such as Poisson's ratio, mass density, and Young's modulus are changed along the z-axis and estimated using genetic programming-assisted micromechanics models from the literature. Initial numerical validation is performed by comparison with a simplified model. The study further explores the effects of GO content and its thickness-direction pattern, and GO folding degree on the wave frequency, phase velocity, and the group velocity. The findings indicate that, in general, the GO-enabled metamaterial plate exhibits a higher wave frequency compared to conventional metallic structures.