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We study experimentally the acoustic response of a load-bearing, phononic crystal composed of alternating steel disks and polytetrafluoroethylene o-rings under precompression. The crystal allows for axial, rocking, and shear-polarized wavemodes when excite ...
The physical mechanism of elastic wave propagation through granular solids is investigated. Based on the symmetry of a one dimensional chain of spheres, spherical surface waves are considered to be responsible for the energy transport. A simple mathematica ...
Internal degrees of freedom and periodic structure are critical requirements in the design of acoustic/elastic metamaterials since they can give rise to extraordinary properties like negative effective mass and stiffness. However, they are challenging to r ...
Wave propagation in granular solids is found to have at least two regimes: a low-frequency ballistic signal and a high-frequency diffusive tail. The latter is attributed to granules clapping or elastic waves within the granules themselves. The low frequenc ...
This contribution is a summary of four lectures delivered by the first author at the CIME Summer school in June 2011 at Cetraro (Italy). Preparation of those lectures was greatly aided by the other authors of these lecture notes. Our goal is to present som ...
Auxetic materials expand when stretched, and shrink when compressed. This is the result of a negative Poisson's ratio ν. Isotropic configurations with ν≈−1 have been designed and are expected to provide increased shear stiffness G. This assumes that Young' ...
Low-frequency waves generated by an impact on an isostatic granular medium with vanishing confinement pressure are theorized to depend on rigid-particle collisions. According to this model, an impact generates a solitary wave spanning several particle diam ...
This paper describes a numerical and experimental investigation on the flexural wave propagation properties of a novel class of negative Poisson's ratio honeycombs with tetrachiral topology. Tetrachiral honeycombs are structures defined by cylinders connec ...
Acoustic lenses are employed in a variety of applications, from biomedical imaging and surgery to defense systems and damage detection in materials. Focused acoustic signals, for example, enable ultrasonic transducers to image the interior of the human bod ...
The chiral lattice is a unique structural network not symmetric to its mirror image, and with a negative Poisson’s ratio. Previous investigations have considered this structural network for the design of superior structural components with sandwich constru ...