A new collaborative study between IMDEA Materials Institute, China’s Northwestern Polytechnical University, the Chinese Academy of Sciences, Peking University, and the Southern University of Science and Technology, has achieved a significant breakthrough in the field of mechanical metamaterials.

Recently published in Nature Communications, the work presents an irregular growth strategy that uses disordered architected materials to achieve static mechanical cloaking and camouflage.

From order to disorder: a new take on architectured materials

Architected materials, whose properties are defined by geometry rather than composition, are revolutionising fields ranging from mechanics and acoustics to robotics and electromagnetism.

Through controlling a material’s architecture: features like its topology, geometry, scale and hierarchy, material distribution and density etc., researchers can develop new materials with tailored properties.

Traditionally, these materials are designed with highly periodic structures that simplify fabrication and modelling. However, nature tells a different story: biological materials such as bone, wood, or insect wings often display irregular internal structures, yet exhibit remarkable mechanical performance.

Inspired by this natural irregularity, the team behind the recent publication explored how disorder itself could become a design principle.

Using a pioneering stochastic growth rule, they developed the new irregular growth strategy that allows the creation of materials capable of mechanical stealth, making internal voids behave as if they were solid, or even mimic the mechanical response of completely different shapes.

Cloaking and camouflage from complexity

When most people hear the word cloaking, they might think of Harry Potter’s invisibility cloak, something that hides an object from sight.

For materials scientists, however, cloaking means something quite different. Instead of making an object invisible to the eye, mechanical cloaking effectively “hides” an internal defect or cavity from stress anddeformation. Through architectured design, the material is engineered so that, under load, it behaves as if the defect didn’t exist.

Camouflage, on the other hand, allows one structure to imitate the mechanical response of another.

Achieving these effects has long been a challenge in mechanics, as traditional transformation-based approaches that work in optics or electromagnetism cannot be directly applied to static deformation fields.

The irregular framework developed in this study overcomes these limitations.

By assembling a small number of building blocks with variable stiffness according to probabilistic growth rules, the researchers engineered mechanical cloaks capable of functioning under diverse boundary conditions and complex void shapes.

The resulting structures exhibit robust performance, maintaining their camouflage capabilities even under non-uniform loading or when embedded in irregular surroundings. Notably, the same methodology can produce mutual camouflage between two distinct void shapes, an achievement unprecedented in static mechanics.

From Simulation to Real Materials

The team validated their design experimentally using 3D-printed prototypes, demonstrating strong agreement between simulation and physical measurements.

The researchers also extended their framework into three-dimensional applications, envisioning potential use cases ranging from protective systems and vibration control to tunnel reinforcement, robotics, and haptic feedback technologies.

In soft robotics, camouflage could enable components to conceal their structural signatures, or biomedical devices, where materials could be designed to replicate the tactile response of human tissue.

Additionally, in virtual and augmented reality, such architectures could form the basis of interfaces capable of producing realistic touch sensations through mechanical mimicry.