Application of inverse analysis for characterization of local material properties in additively manufactured lattice structures

An inverse analysis (IA) procedure was coupled with X-ray Computed Tomography (XCT) data of lattice structures to identify the materials parameters of the lattice and successively predict the macroscopic behaviour of larger structures. The materials parameters were identified by minimizing the deviation between experimental and FEM simulated force–displacement data of a lattice unit cell; the same parameters were input to the simulation of the force–displacement behaviour of larger cells. The agreement between such simulations and the experimental data proved to be excellent. Since both the small- and large-scale cells were tested along the build direction, a simple isotropic material model was considered adequate to rationalize the experimental results. The approach proved that the IA and the FEM simulations are extremely powerful for material parameter identification and for the prediction of the mechanical behaviour of larger structures. We found that the materials parameters of PBF-L IN625 lattices substantially differ from the bulk properties. The latter cannot be used for FEM calculations.