Nanostructure Metamaterial Optimization

Project Overview

The goal of this project was to design a nanostructure metamaterial that is as strong and tough as possible while using very little material.

Objectives

• Maximize strength
• Maximize toughness

Design Constraints

• Infill must stay below 20%

Process

1. Design iteration: I modeled several candidate unit cells in CAD and ran FEA on each one to compare their performance before settling on a final design.
2. Tessellation: I patterned the final unit cell into a 5×5 structure.
3. Fabrication: I manufactured the structure at MIT.nano using two-photon lithography.
4. Testing: I measured its mechanical performance on a nano Instron machine.

Design Iteration

I iterated on the unit cell in CAD, using FEA to check how each design carried load before committing to a final model.

Left: an early unit cell design. Right: FEA of a candidate unit cell, showing von Mises stress.

Fabrication and Testing

After tessellating the final unit cell into a 5×5 structure and printing it with two-photon lithography, I compressed it in a nano Instron.

SEM images of my 5×5 structure in the nano Instron, before (left) and after (right) compression.

Results

Stress-strain curve of my fabricated sample (blue) compared with the class reference sample (orange) we were tasked to outperform.