UC San Diego

The overarching goal of this thesis relies in the exploration of design criteria, such as optimal material layout and geometry, to (1) create and (2) enhance the performance of innovative actuators and sensors, respectively. First, we present a bio-inspired multifunctional active skin, which is a two-dimensional architected material that exhibits local and/or global programmable, rapid, and reversible, out-of-plane surface texture morphing when actuated by in-plane tension. Here, by introducing geometrical imperfection or notches at judiciously chosen locations in a preconceived, auxetic geometry, we can effectively control the directionality of out-of-plane deformations for applications such as camouflage, surface morphing, and soft robotic grippers.

Second, an innovative “sensing mesh” capable of resolving both spatial strain magnitudes and directionalities for distributed strain field monitoring is introduced. The sensing mesh leverages the same concept of patterning to impart unique sensing capabilities in piezoresistive nanocomposites. In particular, the use of a grid-like layout with high aspect ratio struts resolves the strain sensing directionality limitations observed in previously reported sensing skins while also enhancing the sensitivity of the piezoresistive graphene-based thin films once coupled with an electrical impedance tomography conductivity mapping technique.

Finally, the design considerations explored in this thesis contribute to the development of an inverse design methodology of architected materials in which functionality parameters are first indicated and, then, optimal topologies for maximum effectiveness are indicated.