Issues of Designing and Testing Regular Cellular Structures Manufactured Using Additive Technologies

The aim of this paper is to present selected aspects related to designing and testing energy-absorbing regular 2D cellular structures produced using additive manufacturing techniques. The test methodology proposed by the authors included manufacturing structures using two techniques of 3D printing, differing in their manufacturing processes and capacity. The FDM (Fused Deposition Modelling) method enabled the analysis of the deformation process of a wide range of topologies in terms of quasi-static and impact loads. The LENS (Laser Engineered Net Shaping) method allowed for manufacturing structures made of the Ti6Al4V titanium alloy, characterised by a high mechanical strength. The paper presents the most important issues related to testing regular cellular structures under different loading conditions, in particular under dynamic deformation conditions with the use of the split Hopkinson pressure bar (SHPB) technique. The main issues related to the construction of an SHPB station are discussed and the specific nature of testing cellular structures in a classic Hopkinson bar system, as well as in so-called direct impact systems are described. Furthermore, the issues of numerical modelling of cellular structure deformations are discussed at length, with a particular focus on the definition of assumptions necessary for their correct modelling.