Biohydrodynamic Metamaterials
Abstract
The vision for this proposal is to validate a projected order-of-magnitude increase in the efficiency of dissipation of ocean energy relative to the amount of energy dissipated per mass and volume of reef used, compared to both natural and existing engineered reefs, to improve coastal resilience against extreme weather events. Our approach is based on the creation of what we have termed “biohydrodynamic” metamaterials. Metamaterials have macroscopic properties that differ from the microscopic properties of their constituents, and which are determined by their arrangement. The project team has previously shown that a simple set of construction elements can be used to create the highest modulus ultralight materials [Cheung, Kenneth C., and Neil Gershenfeld. "Reversibly assembled cellular composite materials." Science 341, no. 6151 (2013): 1219-1221], and to create mechanical metamaterials spanning rigid, flexural, chiral, and auxetic properties [Jenett, Benjamin, Christopher Cameron, Filippos Tourlomousis, Alfonso Parra Rubio, Megan Ochalek, and Neil Gershenfeld. "Discretely assembled mechanical metamaterials." Science Advances 6, no. 47 (2020): eabc9943]. These were used to realize the long-standing goal of creating morphing aerostructures, by constructing them from simple building blocks [Jenett, Benjamin, Sam Calisch, Daniel Cellucci, Nick Cramer, Neil Gershenfeld, Sean Swei, and Kenneth C. Cheung. "Digital morphing wing: active wing shaping concept using composite lattice-based cellular structures." Soft Robotics 4, no. 1 (2017): 33-48] and these are currently being extended to create morphing hydrostructures to improve the hydrodynamic efficiency of propulsion. The regular construction of these cellular structures provides a basis for robots to automate their construction, using the lattice to locomote, navigate, and error-correct [Jenett, Benjamin, Amira Abdel-Rahman, Kenneth Cheung, and Neil Gershenfeld. "Material–robot system for assembly of discrete cellular structures." IEEE Robotics and Automation Letters 4, no. 4 (2019): 4019-4026]. These prior projects provide the background for the approach in this proposal. But rather than minimizing fluid energy dissipation, the aim will be to maximize it, by guiding the flow field into producing intense multi-directional turbulent jets causing large fluid forces. The high velocity of these jets will not inhibit the biocompatibility of these structures; that will be ensured with a hierarchical construction whereby large structures consist of finer flow-shielding structures, so that the inner space is protected from the intense flow and resulting hydrodynamic forces, providing a biocompatible environment. The one year goal will be to validate an order-of-magnitude improvement in dissipation relative to the mass and volume, as compared to both natural and existing engineered reefs, while maintaining biocompatibility. The former will be tested with a combination of computational fluid dynamics and scale testing in a wave tank. And the latter will be evaluated against both the experimental results and tests with organism growth. These activities will be supported by an evaluation of the materials selection, production processes, and deployment scalability to risk-reduce the transition to field trials.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jul 01, 2022
- Source ID
- HR00112210002
Entities
People
- Neil Gershenfeld
Organizations
- Defense Advanced Research Projects Agency
- Massachusetts Institute of Technology