Additively manufactured lattice structures: An innovative defect-based design methodology against crash impact

It is widely known that defects in lattice structures weaken their mechanical response, resulting in premature failure and affecting their energy absorption capability. In this work an experimental–numerical methodology for the identification of the lower bound design curve of lattice structures subjected to quasi-static compressive and impact tests is proposed and validated on an octet truss lattice structure made of an additively manufactured AlSi10Mg alloy. The defect size distribution is assessed through micro computed tomography and retained in a Finite Element Model (FEM) simulating the mechanical tests by a local reduction of the truss diameter. As the location of critical defects affects the mechanical response, simulations are repeated for different random distributions of the defects within the specimen. Results show that the FEM can correctly predict the mechanical behavior of the lattice structure, with the experimental curves comprised within the band of numerical curves. The lower bound design curve to use for the safe design of components can be finally identified through statistical considerations.