Prediction of Mechanical Responses of Additively Manufactured Lightweight Cellular Structures

Predicting cellular structures' mechanical response to meet application needs is a practical and essential investigation in the field of structural engineering, including manufacturing tools and numerical calculations. This thesis establishes the conceptual, technological, and mechanical foundations for two complementary cellular systems: (i) polymeric grid infill fabricated by fused deposition modeling (FDM) using PLA and (ii) metallic lattices—specifically square‑honeycomb‑type architectures—fabricated by selective laser melting (SLM) using 316L stainless steel. Generally, the framework is on the structural property of cellular materials, focusing on relative density and unit‑cell topology. Firstly, experimental multi‑axial compression of PLA infill cubes through infill ratios and raster angles has been made to quantify the role of raster angle and infill ratio on the stiffness of transversely isotropic lattices. Additionally, by multi‑scale finite‑element models with conventional modeling and a more sophisticated approach, integrating micro/meso/macro unit cells under periodic boundary conditions, a numerical methodology was used to increase the accuracy in predicting the mechanical behavior, while keeping the modeling complexity moderate. Afterward, an internally pressure‑loaded metallic cylindrical lattice was tested to link geometry, process constraints, and realized stiffness. This research started with designing a prototype of cellular architected SLM 316L honeycomb. A specific test rig was provided to apply pneumatic/hydrostatic pressurization on the 3D printed specimens. To understand the homogenized behavior of the target cells, a multi‑directional compression test was carried out. While experimental data provided an overall behavior of the structure, FEM was used to get additional information about the deformation and stress distribution. The thesis combines design, experiment, and simulation to deliver an industrial-level roadmap to predict mechanical behavior in AM cellular structures. Connecting the employed methodologies is beneficial to respond to industrial problems and make the use of new and advanced technologies in manufacturing with less risk and faster results.