Determination of anisotropic elastic constants of additively manufactured Ti–6Al–4V with complex geometry

Additive manufacturing offers unparalleled design flexibility; however, its unique processing principles often lead to mechanical anisotropy that critically affects the load-bearing performance of structural components. Furthermore, determining elastic constants in complex-shaped materials requires considerable effort when using conventional mechanical testing methods, owing to the need for simplified specimen geometries and multiple loading configurations. In the present work, the elastic constants of an as-built additively manufactured Ti–6Al–4V alloy were evaluated by resonant ultrasound spectroscopy (RUS) assisted by a vibration-mode pattern-matching scheme. A vibration analysis incorporating iterative calculations was conducted using an analytical model derived from the measured geometry of the as-built specimen, in which nine independent elastic constants were identified to reproduce the resonance frequencies obtained from experimental vibration tests under matching vibration-mode conditions. The measured elastic constants were reasonably consistent with those obtained from tensile tests performed on rectangular tensile specimens extracted from the specimen, as well as with values in the literature. The largest deviation was observed for ν 23 ; however, the absolute difference was only 0.02 (7.4%). The results further indicate that, under vibration-mode-matching conditions, the elastic constants can be measured using RUS with only 17–21 resonance frequencies, corresponding to approximately half of the number conventionally required relative to the number of unknown parameters. The results demonstrate that the proposed approach provides a practical pathway for evaluating process-induced anisotropy in real components, which is critical for design and structural integrity assessment of additively manufactured parts.