Design ultralight and strong metamaterials

Abstract

A new technology emerging in today’s world is additive manufacturing with steel. Investigating how different micro-lattices perform under different loading conditions is a key component for implementing this new technology into every day mechanical components. This project looks at how five different micro-lattices perform under the four standard modes of loading and a combined loading scenario. The four standard modes of loading are tension, compression, pure shear, and bending. The combined loading scenario consists of combining shear and compression. The material properties of the EOS MaragingSteel 1 material need to be determined prior to performing computer simulations. Test specimens need to be machined down to the appropriate specifications, known as the dog-bone. These test specimens are designed to fracture at a specific point so that stress, strain, yield stress, and ultimate tensile stress can be determined. The axis in which the test specimens are printed must also be considered as some material properties may change. The project includes a mechatronics component that involves embedding a strain gauge sensor along the exterior bounds of the lattice. The starting point for the strain gauge is a hard-wired unit which is then modified to communicate the data wirelessly. This would provide useful information during the testing of a final micro-lattice structure, and also demonstrate how this could be used in industry to monitor parts that are currently in service. The results of all computer simulations were reviewed and the octet-truss microlattice was chosen, because overall it has the preferred performance characteristics under the different loading conditions. The final micro-lattice will not at this time be printed due to financial restrictions. The test results from the physical micro-lattice specimen would have been compared to the results of the computer simulations, in order to verify the simulations. The octet-truss, diamond, pyramid, block lattice truss, and cubic truss unit cells were modeled and built into micro-lattice structures using Autodesk Inventor and Fusion 360. For the simulations of the loading conditions, the constraints and the loading conditions for the lattices were applied to the models using Fusion 360, and the simulations were performed using the Autodesk Nastran software.