Artificially engineered lattice structrures, also known as metamaterials, are progresively moving from the theoretical realm to practical applications, due to theorerical findings and, especially, the possibility of 3D printing them. Largely developed for electromagnetic devices, new ideas are emerging for mechanical uses, almost invariably related to linear elastic and wave propagation phenomena. As a result, there already exist physical devices (and patents) that exploit the taylored structure to steer waves, provide acousting impedance, etc. It is widely recognised, however, that a great potential lies on the design of metamaterials whose nonlinear response is harnessed. The mathematical complexity of the corresponding mathematical models has greatly hindered new developments in this area and promised opportunities remain largely unexplored.

In view of these circumstances, the project investigates lattice designs that result in metamaterials capable of absorbing mechanical energy in their nonlinear regime, while having the ability to recover their original shape upon heating. The innovative idea behind these materials consists in realising that structural lattices can be designed whose mechanical response replicates the micro-mechanisms that give rise to the shape memory effect in conventional materials. The project identifies the key geometric and energetic requirements for the meso-structure and suggests a possible prototype based on nonlinear beams that satisfies all of them.

A full understanding of this complex behavior will be explored in the project, using numerical methods for nonlinear structures developed in the group and stability analyses of the thermomechanical response. The results will fully characterise the macroscopic response of such metamaterials, clasify the parameter space and energy landscape, and finally determine the technological viability of the designs.