Mechanical Metamaterials Design and Numerical Modeling versus Experimental Characterization in Statics and Dynamics

Since the Industrial Revolution, the scientist’s principal challenge has been to find materials with the best possible characteristics. However, it is well known that the requirements are often not easy to accomplish. Especially in this age, the possibility of fine-tuning devices and structures to obtain the best performance most efficiently has become crucial. In this perspective, metamaterials are appealing solutions to accomplish this complex task. The definition itself expresses their whole potential: a metamaterial is a structure whose response does not depend only on the constitutive material but mainly on the geometric configuration. The metamaterials concept paves the way for several engineering applications that would benefit from employing such structures. The principal topic of this thesis is metamaterials, with a particular focus on their dynamic behavior. The developing path starts with analyzing the static response of folded metamaterials. This preliminary step is fundamental for preparing the ground to analyze dynamic phenomena. The following part of the thesis deals with the modal response of folded materials, entering for the first time into a problem that involves dynamical aspects. The last part of this thesis is the study of non-reciprocal wave propagation through a nonlinear chain metamaterial. The non-reciprocity phenomena are sought for their interesting mathematical modeling in the scientific community. Furthermore, the non-reciprocity might also impact engineering applications as a strategy to harvest energy or direct mechanical energy in a specific direction. The multidisciplinary analyses pursued in this thesis are both numerical and experimental, with a particular dedication to the latter, which is the main thread of this work.