Image-based numerical modeling of the tensile deformation behavior and mechanical properties of additive manufactured Ti–6Al–4V diamond lattice structures

Abstract

This work concerns the numerical modeling of the deformation process and mechanical properties of structures obtained by the additive method laser power bed fusion (LPBF). The investigation uses diamond structures of Ti–6Al–4V titanium implantation alloy with various relative densities. To model the process of tensile deformation of the materials, geometric models were used, mapping the realistic shape of the examined structures. To recreate the geometry of the samples, computed tomography (CT) and microtomography (micro-CT) were used, which allowed to obtain two accuracy levels of the mapping details of the investigated structures shape. Taking into account the nonlinearity of the material in the computational model makes it possible to model the deformation process of cellular materials until the fracture initiation. On the basis of the performed calculations using the finite element method (FEM), the stress and strain distributions in deformed structures were obtained and analyzed. The relationship between the shape of cellular structures and their effective mechanical properties on a macroscopic scale was investigated. The influence of the accuracy of the structures shape mapping on their strength properties and stress and strain distributions was also described. On the basis of the conducted research, fracture initiation localizations in titanium cellular structures were indicated. Finally, the results of the numerical calculations were verified by experimental tests.