Arbitrary-shape transformation multiphysics cloak by topology optimization

Transformation theory has enabled the booming development of metamaterials which have offered powerful capability to control different physical fields, and the remaining challenges lie in the robust design of extremely anisotropic material parameters. Such challenges surge for multiphysics metamaterials is more difficult though not impossible. Previous studies on multiphysics metamaterials have neither established a general framework nor tackled the limited shape adaptivity beyond the scattering cancellation technique. Here, those challenges are successfully addressed by the transformation multiphysics cloak (TMC), through which a general design framework is established under the discretion-and-assembly strategy with topology optimization. As proof-of-concept, we design an arbitrary-shape TMC to achieve the simultaneous cloaking of heat and electric current transiently and steadily, which is validated by both numerical simulations and experimental measurements. The proposed method may trigger unprecedented development of multiphysics metamaterials in other physical fields with integration of more functionalities, shape adaptivity, and application scenarios.