Examination of the geometry-dependent anisotropic material behavior in additive layer manufacturing for the calculation of mesoscopic lightweight structures

Due to the producible geometric complexity, additive layer manufacturing (ALM) processes show a high potential for the production of lightweight components. Especially mesoscopic approaches, like honeycombs or lattice structures, exhibit very advantageous mechanical properties like stiffness or strength combined with low masses. To achieve an optimum structure, a regular buildup out of equal elementary cells is not ideal. Rather, an adjustment of the course of the structure and its material filling degree has to be done. Therefore, detailed knowledge about the material behavior of additive manufactured components is necessary. Especially for lightweight structures, these properties are affected by anisotropy and geometry dependent influences. These effects have a severe influence on the basic elements of mesoscopic patterns, like struts in case of lattice structures or the single walls of honeycombs. In case of anisotropy this means that the material behaviour - and even the success of the build-up process - of the basic elements depend on the angle, under which the strut or honeycomb is built in relation to the building direction. In case of geometry dependency, this means that the material behavior is influenced by several geometric attributes. For lattice structures, this can be the lengths or the cross section of the struts. In the field of honeycombs, the height and broadness as well as the thickness of the walls can be mentioned. While there are already numerous analyses concerning the orientation dependent anisotropy, the influences of the geometric properties have not been researched, yet. To achieve best possible mesoscopic structures in lightweight components, these influences have to be taken into account. Therefore, a material model for struts in lattice structures, including the corresponding experimental results, will be introduced in this paper. This model takes anisotropic and geometry-dependent aspects into account and therefore provides a basis for a successful calculation and optimization of lattice structures.