This work showcases a novel phenomenological method to create predictive simulations of metallic lattice structures. The samples were manufactured via laser powder bed fusion (LPBF). Simulating LPBF-manufactured metamaterials accurately presents a challenge. The printed geometry is different from the CAD geometry the lattice is based on. The reasons are intrinsic limitations of the printing process, which cause defects such as pores or rough surfaces. These differences result in material behavior that depends on the surface/volume ratio. To create predictive simulations, this work introduces an approach to setup a calibrated simulation based on a combination of experimental force data and local displacements obtained via global Digital Image Correlation (DIC). The displacement fields are measured via Finite Element based DIC and yield the true local deformation of the structure. By exploiting symmetries of the geometry, a simplified parametrized simulation model is created. The simulation is calibrated via Response Surface Methodology based on nodal displacements from FE-DIC combined with the experimental force/displacement data. This method is used to create a simulation of an anti-tetrachiral, auxetic structure. The transferability and accuracy are discussed, as well as the possible extension into 3D space.

This work discusses a novel approach to simulate metallic auxetic structures manufactured via Selective Laser Melting (SLM). SLMmanufactured metamaterials are difficult to simulate accurately based on nominal geometry and bulk material behaviour. The geometry after printing is different from the nominal CAD geometry. Artefacts due to the printing process such as pores yield a material behaviour which depends on the surface/volume ratio. We investigate a phenomenological approach to obtain a simulation model calibrated with experimental data and Digital Image Correlation (DIC). Finite Element based global DIC as suggested by Hild [1,2] allows for obtaining accurate displacement fields, consistent with the true deformation of the lattice structure. Based on the nominal CAD geometry, a simplified parametrized simulation model is created, exploiting the abundant symmetries of lattice structures. Using nodal displacements from DIC in combination with the expected forces from an experiment, the model is calibrated via LS-OPT. The approach is applied to an antitetrachiral, auxetic structure. Furthermore, we discuss the accuracy of the approach, its applicability to other structures and possible extension into 3D space.