Planar Soft Functional Periodic Structures Exploiting Instabilities and Large Deformation

Abstract

Soft materials can significantly change their shape and volume when subjected to various stimuli. Materials with deliberately designed periodic microstructure have long been proved to be characterized by properties that may exceed those of the corresponding bulk material. Though traditionally avoided as modes of failure, mechanical instabilities have recently been exploited to design systems with novel and tunable functionalities. Interestingly, the studies I conducted during my PhD show that the combination of soft materials, periodic structures, mechanical instabilities and large deformation give us the opportunity to design materials and structures with enhanced functionality. In this thesis, I present a systematic study on the response of planar sof୴ functional materials which use their large deformation and geometric rearrangements to dramatically change their properties. In particular, I used a combination of experiments and numerical simulations to investigate the effect of important parameters, such as pore shape, hole arrangement and loading conditions. With the fundamental understanding I gained, I developed a novel class of planar soft periodic materials with enhanced material functionalities such as tunable phononic band-gap, spontaneous symmetry breaking, chirality amplification and energy trapping. Remarkably, since the continuous 2D soft and porous structures I studied take advantage of reversible and scale-independent mechanisms, the proposed designs can be applied over a wide range of length scales. The studies presented here show that by mastering the interplay between the microstructure of soft periodic structures and their large deformation behavior, novel materials with enhanced func