Understanding the microstructural role of bio-sourced 3D printed structures on the tensile performance

This study aims at revealing the role of microstructural arrangement on the mechanical behaviour of printed PLA-Hemp using Fused Deposition Modelling (FDM). 3D printing is performed by varying the printing temperature. The laying down process is monitored using infra-red measurement. X-ray micro-tomography is used to acquire the 3D microstructure of printed PLA-Hemp. Tensile performance is determined by testing neat and notched specimens. Finite element modelling based on microstructure implementation is conducted to reveal the deformation mechanisms associated with the tensile loading. The results show a wide temperature range for printability of PLA-Hemp but overheating effects characterises the printing using large temperatures ( > 220 degrees C). The tensile performance is found dependent on the printing temperature, a modified filament morphology, and an imperfect nature of the hemp-PLA interface within the filament. Finite element results reveal particular characteristics of stress fields that superpose with underlined microstructure of filament arrangement. Despite this correlation, the low porosity level and the brittle nature of the filament do not allow strong dependence of the crack propagation on the raster orientation.