Nonlinear elastic waves in architected soft solids

Abstract

In this presentation, we analyze different regimes of elastic wave propagation in a family of architected soft solids, the rotating square structures, known to exhibit negative Poisson ratio. We show that it is possible, via a discrete model of finite size masses coupled by soft and highly deformable elastic ligaments, to describe the nonlinear wave propagation of displacement and rotation modes in a two-dimensional configuration. In turn, the geometrical characteristics and local elastic parameters of the architected structures can be put in correspondence with the dispersive and nonlinear wave properties, thus allowing for the dispersion and nonlinearity management. By exploring several designs and the influence of geometry, we show that the parameters of the governing nonlinear wave equations can be controlled, and even the type of governing equation and their dominant nonlinearity can be modified. In particular, we report that for several studied configurations, vector elastic solitons are predicted and experimentally observed. These results could be useful for the design of nonlinear elastic metamaterials, aiming at controlling high amplitude vibrations and elastic waves, or achieving amplitude dependent operations on waves.