Multi-Scale Characterisation and Modelling of Additively Manufactured Grid Structures

Gitterstruktur — grid structure reconstructed from CT-data for identification of process induced imperfections

Additive manufacturing lifts the restrictions of conventional manufacturing techniques and enables us to produce complex geometries, such as grid structures. The layer wise manufacturing results in anisotropic material properties and high thermal gradients cause residual stresses in the manufactured component.

Using additively manufactured complex structures in techniqual applications requires reliable modelling approaches to describe the resulting properties. In cooperation with the Leibniz Institute for Solid State Materials Research Dresden, the Leichtbauzentrum Sachsen GmbH and the Chair for Numerical and Experimental Solid Mechanics at TU Dresden a multi-scale approach for grid structures made out of AlSi10Mg by SLM (selective laser melting) ist therefore developed.

The basic material is characterized through tensile tests with additive manufactured test specimens and the modelling of a unit cell evaluates effective mechanical material properties of the grid structure. Process induced imperfections are identified using reverse engineering in cooperation with the Chair of Engineering Design and CAD at TU Dresden. Those imperfections are quantitavely considered in the modelling of the unit cell and the resulting effective material parameters are applied on a homogenous test specimen for virtual testing. Finally virtual experiments are performed on a in detail modelled grid structure and real experiments with manufactured test specimens for tensile, shear, pressure and torsion tests are performed for validation of the theoretical results.