Optimized infill density through topological optimization increases strength of additively manufactured porous polylactic acid.

The objective of this paper is to determine the impact of density fraction on the mechanical properties of 3D printed thermoplastic materials to maximize the mechanical strength of parts through a combination of topology optimization and tailored density fraction. The results obtained reveal a significant finding of the applicability of the strategy for improving additive manufacturing processes, design automation, and manufacturing of high-strength components. The effect of infill density and print orientation on the mechanical properties of PLA-based 3D-printed parts are quantified by ultimate strength and Young's modulus in two material orientations (in the printing direction and out of the printing plane), employing both experimental and simulated uniaxial tensile tests, a polynomial relationship as a function of density fraction is determined. These data are then used in a series of successive topological optimizations of a part subjected to operational loads that maximize strength with a targeted reduction in the overall mass. The resulting optimized part exhibits a discrete density fraction distribution from the overlapped topologies that allows the total mass of the original part to be maintained with a 258% increase in load-carrying capacity before failure and a mere 23% increase in fabrication time by fused deposition modeling. These findings underscore the promise of leveraging advanced 3D printing methods and topology optimization to enhance the strength and efficiency of manufactured components. [ABSTRACT FROM AUTHOR]