Micro-Scale Auxetic Hierarchical Mechanical Metamaterials for Shape Morphing

Shape morphing and the possibility of having control over mechanical properties via designed deformations have attracted a lot of attention in the materials community and led to a variety of applications with an emphasis on the space industry. However, current materials normally do not allow to have a full control over the deformation pattern and often fail to replicate such behavior at low scales which is essential in flexible electronics. Thus, in this paper, novel 2D and 3D microscopic hierarchical mechanical metamaterials using mutually-competing substructures within the system that are capable of exhibiting a broad range of the highly unusual auxetic behavior are proposed. Using experiments (3D microprinted polymers) supported by computer simulations, it is shown that such ability can be controlled through geometric design parameters. Finally it is demonstrated that the considered structure can form a composite capable of shape morphing allowing it to deform to a predefined shape.

Automated summary

In this paper, a novel hierarchical mechanical metamaterial is proposed that can exhibit a wide range of unusual auxetic behavior. The ability to control this behavior through geometric design parameters is demonstrated using experiments and computer simulations. The proposed structure is capable of shape morphing, making it suitable for various applications, including flexible electronics.