Metamaterials can be used to alter the electromagnetic properties of a material. Often, however, it is desirable that the material also serve as a load-bearing or structural element, such as the hull of a ship or the wing of an airplane. An important research thrust at CMIP is the integration of metamaterial elements into layered and sandwich composites-such as glass or carbon fiber structures-to develop multifunctional composites with tailored and possibly reconfigurable electromagnetic properties. The design of materials with tailored structural, dynamic and electromagnetic properties represents a step further in the development of materials that meet the strict requirements imposed by aerospace and aeronautical engineering fields.
All issues associated with multifunctional composites are of interest at CMIP, from the potential applications of such structures to their detailed fabrication and characterization. Related topics-not necessarily restricted only to composites with electromagnetic functionality-currently under investigation are the integration of self-healing and sensing functionalities in hybrid composite metamaterials. An example of a self-healing composite is a carbon fiber reinforced healable composite, in which the matrix is capable of mending internal fractures. For sensing, integrated micro-sensors, potentially connected into networks via wireless links, may actively monitor the status of internal damage in real-time while the structure is in service conditions. The integration of periodically positioned modular micro-circuitry elements, transducers and actuation elements, networked together to achieve monitoring and actuation needs, must be fully compatible with the surrounding host composite.
Because embedded elements tend to act as stress concentrators within a composite, the structural performance characteristics of the metamaterial/composite hybrid are susceptible to degradation. A key challenge, then, is to find strategies to implement the desired metamaterial properties without obviating the structural properties of the composite. Fabrication techniques aiming at miniaturizing electronic components to be integrated into advanced composite materials represent one aspect of this research area.
The correlation of the structural and dynamic performance of the composite under varying load and environmental conditions with the associated changes in the electromagnetic properties can eventually lead towards materials with optimized electro-mechanical characteristics.
In short, CMIP is dedicated to transferring the unique properties and capabilities of metamaterials to structural composites with both passive as well as reconfigurable electromagnetic properties.