Bistable Auxetic Mechanical Metamaterials
A. Rafsanjani and D. Pasini, Bistable Auxetic Mechanical Metamaterials Inspired by Ancient Geometric Motifs. Extreme Mechanics Letters 9, 291-296 (2016).
architected materials
Snapping Mechanical Metamaterials under Tension
We present a monolithic mechanical metamaterial comprising a periodic arrangement of snapping units with tunable tensile behavior. Under tension, the metamaterial undergoes a large extension caused by sequential snap-through instabilities, and exhibits a pattern switch from an undeformed wavy-shape to a diamond configuration.
Design of planar isotropic negative Poisson’s ratio structures
Most of the auxetic materials that have been characterized experimentally or studied analytically are anisotropic and this limits their possible applications, as they need to be carefully oriented during operation. Here, through a combined numerical and experimental approach, we demonstrate that 2D auxetic materials with isotropic response can be easily realized by perforating a sheet with elongated cuts arranged to form a periodic pattern with either six-fold or three-fold symmetry.
Multistable Architected Materials for Trapping Elastic Strain Energy
3D printing and numerical analysis are combined to design a new class of architected materials that contain bistable beam elements and exhibit controlled trapping of elastic energy. The proposed energy-absorbing structures are reusable. Moreover, the mechanism of energy absorption stems solely from the structural geometry of the printed beam elements, and is therefore both materials- and loading-rate independent.
http://onlinelibrary.wiley.com/doi/10.1002/adma.201501708/full