Analysis of a 3D tetrachiral auxetic lattice under compression: Combining experimental and numerical approaches of 4D X-ray microtomography, digital volume correlation, and finite element modeling

Abstract We studied compression of tetrachiral auxetic lattice manufactured using laser powder bed fusion from an aluminum alloy. Using an in-house loading device integrated with an X-ray CT scanner, experiments, including in-situ loading with time-lapse XCT imaging, were performed to obtain 3D images of the lattice to study its geometry, internal structure, and deformation through an in-house digital volume correlation. Numerical analyses based on the voxel model from XCT imaging and the tetrahedral model based on the design geometry were performed. The correlation between the experiment and the simulations was sought by comparing force-displacement diagrams and Poisson’s ratio. Results show that 3D printing of the lattice may lead to significantly different mechanical characteristics. An analysis of the difference between the design geometry and the manufactured lattice, coupled with porosity assessment, was performed to discuss the reasons for the discrepancies between the anticipated deformation response of the lattice and its real behavior.