  3D printing technology offers the possibility of producing synthetic samples
with accurately defined microstructures. As indicated by effective medium
theory (EMT), the shapes, orientations, and sizes of voids significantly affect
the overall elastic response of a solid body. By performing uniaxial
compression tests on twenty types of 3D-printed samples containing voids of
different geometries, we examine whether the measured effective elasticities
are accurately predicted by EMT. To manufacture the sample, we selected
printers that use different technologies; fused deposition modelling (FDM), and
stereolithography (SLA). We show how printer settings (FDM case) or sample cure
time (SLA case) affect the measured properties. We also examine the
reproducibility of elasticity tests on identically designed samples. To obtain
the range of theoretical predictions, we assume either uniform strain or
uniform stress. Our study of over two hundred samples shows that measured
effective elastic moduli can fit EMT predictions with an error of less than 5%
using both FDM and SLA methods if certain printing specifications and sample
design considerations are taken into account. Notably, we find that the pore
volume fraction of the designed samples should be above 1% to induce a
measurable softening effect, but below 5% to produce accurate EMT estimations
that fit the measured elastic properties of the samples. Our results highlight
both the strengths of EMT for predicting the effective properties of solids
with low pore fraction volume microstructural configurations, and the
limitations for high porosity microstructures.
