Mechanical and morphological characterization of spherical cell porous structures manufactured using FDM process

Abstract

The mechanical behavior and the deformation characteristics of porous polylactide acid (PLA) structures manufactured additively to different morphologies under quasi-static uniaxial compression are investigated in this paper. The PLA porous specimens are designed by CAD and manufactured with fused deposition modeling (FDM). The effects of macrostructure and compression direction compared to layer deposition strategy on the way of deformation and crushing behavior of PLA structures are studied. The loading directions are parallel and perpendicular to the direction of manufacture. The experimental results indicated that the PLA structures with hexagonal stacking, open porosity and loading direction parallel to the manufactured direction show good performances since Young modulus, plateau stress and densification strain. In addition, structures with square stack are more likely to induce local collapse during compression test and stable deformation process. Furthermore, the results revealed that PLA structures with parallel direction have higher strength and smaller lateral expansion than those with perpendicular direction. The most interesting microscopic observation is that the cellular structures based on closed porosity and parallel direction presented a deformation behavior dominated by walls buckling. However, the cellular structures based on perpendicular direction showed the presence of cracks between the layers and following direction of loading.