Topological defects in complex mechanical metamaterials

While topological defects play a crucial role in condensed matter, they are not widely explored in mechanical metamaterials. We introduce a systematic strategy to design frustrated metamaterials with local or topological defects. We uncover their distinct mechanical signatures, and show how defects can be harnessed to engineer a desired response. Our work presents a new avenue to systematically introduce frustration and defects with a topological signature in mechanical metamaterials.