Multiscale analysis for predicting elastic properties of 3D printed polymer-graphene nanocomposites

Abstract

The use of graphene-based nanocomposite materials is increasing in additive manufacturing (or 3D printing) technology. This work focuses on evaluating the elastic properties of 3D printed components using PLA/graphene nanocomposite material. The filler morphology at the nanoscale and process parameters such as printing layer orientation at macroscale affect the final mechanical properties of printed parts. We used FE-RVE based numerical approach to estimate the elastic modulus of printed parts at two different scales. At the nanoscale, RVE is constructed using filler and matrix morphology. The modulus calculated is used as an input to the macroscale RVE which is built using the printing process parameters and deposited bead dimensions. The boundaries of the RVE domain are subjected to multi-nodal periodic boundary conditions, and homogenized properties were calculated. Experiments have been conducted to validate numerically calculated modulus values. Tensile test samples have been 3D printed according to ASTM D638 standard and tested at 1 mm/min. The numerically estimated modulus values are in close agreement with experimentally obtained values. Further, parametric studies have been carried out to investigate the effect of print layer thickness and orientation on the modulus of 3D printed parts. The two-scale numerical approach presented here can predict the elastic properties of 3D printed parts.