Simultaneous Thermal–Electrical Cloak and Camouflage Via Level-Set-Based Topology Optimization

Abstract

Cloaks are devices designed to conceal objects from detection. With the advancement of metamaterials, there is an increasing interest in developing multifunctional cloaks to cater to various application scenarios. This article proposes a level-set-based shape and topology optimization scheme to design simultaneous thermal and electrical cloaking devices. Unlike classical methods such as coordinate transformation and scattering cancelation, which are vulnerable to high material anisotropy, the proposed method employs only naturally occurring bulk materials, greatly facilitating physical realization. The bifunctional cloak is achieved by reproducing the reference temperature and electrical potential fields within the evaluation domain through the optimal layout of two thermally and electrically conductive materials. Using a similar formulation, we extend the proposed method to design a thermal–electrical camouflage device that can conceal a sensor while allowing it to remain functional. This study presents a method to simultaneously achieve sensing and camouflaging in multiphysical fields using topology optimization. Previous research has generally addressed these functionalities separately; in contrast, we integrate them into a unified framework. To demonstrate the method’s potential, we provide examples of bifunctional cloaks and camouflage devices. The dependency of the optimization results on the initial designs is also briefly investigated. Despite exhibiting a notable reliance on the initial guesses, as with any gradient-based method, the objective functions based on the least-square error are sufficiently small, demonstrating the effectiveness of the cloak. This study holds promise for inspiring further exploration of metadevices with multiple functionalities.