Research Overview

  • Origami Metamaterials for Tunable Thermal Expansion
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The overarching goal of the research group is to contribute to the fundamental understanding of the non-linear response of materials and structures. While engineering applications often use stiff and almost rigid materials, materials capable of undergoing large deformations like elastomers and gels are ubiquitous in  daily life and nature. An exciting field of engineering is emerging that uses these compliant materials to design a new class of active devices, such as actuators, adaptive optical systems  and self-regulating fluidics.

Structures made of elastomers and gels may significantly change their architecture in response to diverse stimuli. When excessive deformation is applied, they may eventually become unstable. Beyond the instability threshold, rapid and dramatic changes of the structural geometry occur and careful design of the initial architecture may lead to the formation of new periodic patterns.

We exploit the non-linear behavior of highly deformable structures to create a new class of adaptive materials that use large deformations and dramatic geometric rearrangements induced by instabilities to rapidly tune their functionalities. Topological changes associated with instabilities are intentionally pursued as an effective approach for tuning the macroscopic response of the structure. Possible and exciting applications include the design of novel materials with adaptive wave propagation characteristics, reversible encapsulation systems, active materials for on-demand drug delivery, robots that can squeeze themselves through small openings and into tight places and materials with unusual properties such as negative Poisson's ratio.

To design structures and devices made by highly deformable materials, the theories that describe their response must be implemented within software. In these materials mechanics, chemistry and electrostatic work together to generate large deformations and both the phenomena and the engineering applications have motivated the development of theories of diverse soft active materials.  We implemented such theories into a widely available commercial Finite Element package (Abaqus) and successfully investigated the non-linear response of structures responsive to diverse stimuli.

To gain deeper insight into the non-linear behavior of materials and structures, we use an approach based on a powerful combination of computational analyses and experiments. Numerical analyses permit a deep understanding of the experimental results; on the other hand experiments stimulate the development of analyses able to capture the behavior observed during the tests. We focus both on the development of computational tools and proof-of-concepts experiments at the centimeter scale. Moreover, since the design of a new class of active structures requires a wide range of expertise, we are collaborating with a number of groups both inside and outside SEAS.