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’’Can you shape the feel of a thing ?’’ : Tunable mechanical meta-materials
We probe the mechanical response of 2d elastic media, structured by a crystalline pattern of holes of two different sizes. While compressed under uniaxial loading, the holes pattern transforms, the overall material undergoes an auxetic mechanical response. Hole size and aspect ratio play a crucial role on this mechanical response, and eventually lead to a negative stiffness. Further biaxial loading leads to a wealth of new phenomena, including mechanically switchable hysteresis and memory effects. Using extensible beams as a model building block, we identify some key parameters that describe the various instabilities that can occur.
