A generic design motif for metamaterials with controllable nonlinearity & guided deformation

Abstract

Structure design motifs take an essential role in creating materials or metamaterials with superior mechanics or special functions. However, a fundamental question naturally arising and remaining unknown is related to how to effectively design an engineered material structure with “adjustable and predictable” nonlinear mechanic properties conveniently. Here we propose a very simple but versatile design motif, named as bq-structure, which can provide superior flexibility in achieving various nonlinear properties, including 200 % larger and designable ranges of quasi-zero stiffness, negative stiffness, and multi-stable stiffness, etc, that original material or traditional beam-based design motifs cannot provide. The proposed design motif has sufficient reliability in nonlinear manipulation with a “guided & controllable” manner instead of “trail-and-error attempts” existing in most existing ones. A prototyped vibration isolation unit can achieve a resonant frequency less than 1 Hz easily which cannot be done with many other methods of similar size and payload. Given the large elastic deforming capacity and ductility in structural scale, the superb nonlinearity regime is generally designable with various structure parameters, uniquely providing a superior optimization tool with this novel design motif considering various real application requirements for advanced materials design, energy storage or conversion, mechanical vibration mitigation, and robotic systems etc.