Mechanical performance of hexagonal close-packed hollow sphere infill structures with shared walls under compression load

Abstract

Infill structures of additive manufactured components give not only stability, but can be used as a design feature regarding lightweight and mechanical properties. In this study, an infill structure was investigated which consists of hollow spheres in a hexagonal closed packing. An additional characteristic is, that the contact between the spheres is modelled as an intersection. A script-based design approach was used for generating the structure within a cylinder. Thus, the sphere diameter, the sphere wall thickness and the outer shell thickness can be varied. The deformation behavior was studied using the Finite Element Method (FEM). Compression tests on additive manufactured cylindrical specimens verify the FEM results: (1) appropriate modelling of the contact between the spheres enhances the stability to the structure. (2) Increasing the relative density increases the mechanical properties. (3) Lower values for the relative sphere wall thickness result in an improved ductility.