We study the propagation of in-plane elastic waves in a soft thin strip, a specific geometrical and mechanical hybrid framework which we expect to exhibit a Dirac-like cone. We separate the low frequencies guided modes (typically 100 Hz for a 1-cm-wide strip) and obtain experimentally the full dispersion diagram. Dirac cones are evidenced together with other remarkable wave phenomena such as negative wave velocity or pseudo-zero group velocity (ZGV). Our measurements are convincingly supported by a model (and numerical simulation) for both Neumann and Dirichlet boundary conditions. Finally, we perform one-way chiral selection by carefully setting the source position and polarization. Therefore, we show that soft materials support atypical wave-based phenomena, which is all of the more interesting as they make most of the biological tissues.

我们研究了平面内弹性波在软薄带中的传播，该薄带是一种特定的几何和机械混合框架，我们希望它表现出狄拉克样的圆锥。我们分离出低频引导模式（对于1 cm宽的带通常为100 Hz），并通过实验获得完整的色散图。狄拉克锥与其他显着的波现象（例如负波速度或伪零群速度（ZGV））一起被证明。模型（和数值模拟）为Neumann和Dirichlet边界条件提供了令人信服的支持。最后，我们通过仔细设置光源位置和极化来执行单向手性选择。因此，我们表明软材料支持基于非典型波的现象，当它们构成大多数生物组织时，这将变得更加有趣。