Auxetic behavior of Ti6Al4V lattice structures manufactured by laser powder bed fusion

Abstract

The design parameters of re-entrant honeycomb (RH) unit cells are effective in determining the auxetic structures' behavior. This study examines the auxetic response of Ti6Al4V lattice structures fabricated using laser powder bed fusion (L-PBF), focusing on cell parameters (re-entrant angle (theta), inclined strut length (l), and strut thickness (t)). The auxetic behavior of structures was observed numerically with finite element analysis (FEA) carried out by nTop and experimentally with quasi-static compression tests. The results presented that the minimum Poisson's ratios (PRs) were obtained as -1.48 and -1.10 for simulation and experiments, respectively. As the absolute value of the PR increases, the auxetic behavior becomes more obvious. The absolute value of the PR increased with the increases in theta and l, while decreased with the increase in t. The findings of this study offer an important contribution to the development of auxetic structures by adjusting the design parameters.