Application of composite material models to determine the Young’s modulus of the grid pattern of partially infilled 3D printed samples

Abstract

Additive manufacturing makes it possible to fabricate samples with partial internal infill. This type of sample has a different Young´s modulus than a completely filled sample. In this work, the dependence of the apparent Young´s modulus of samples manufactured by 3D printing on the infill percentage has been experimentally determined, for a given pattern and using a non-destructive technique. Young´s modulus was assumed as an apparent modulus and values were found between 3.39 GPa for the sample with 100% infill and 1.32 GPa for the sample with 20% infill. In particular, a non-linear variation of the apparent Young´s modulus was observed. The specific Young´s modulus presents a minimum for an intermediate infill percentage. The use of a model of composite materials was proposed, as a first approach to determine the apparent Young´s modulus of the parts. The mixture law, the Halpin-Tsai equation generalized by Kerner, a model of foams and the Mori Tanaka method were applied to the dependence of the apparent Young´s modulus on the infill percentage, giving all, except the mixture law, acceptable results. The advantage of applying each model was discussed. This type of analysis would allow a fast semi-empirical approach of the apparent Young´s modulus in partially filled samples with a grid pattern.