Anisotropic elastoplastic constitutive modeling of additively manufactured Strut-Based lattice structures

This study establishes a systematic experimental methodology for calibrating anisotropic elastoplastic constitutive models of additively manufactured strut-based lattice structures, with anisotropy originating from structural topology, manufacturing-induced geometric deviations, and the anisotropic crystallographic texture of the base material. Focusing on Ti-6Al-4 V lattices with body-centered cubic (BCC) and face-centered cubic (FCC) topologies fabricated via laser powder bed fusion (LPBF), we systematically applied the Xue-Hutchinson anisotropic compressible yield criterion coupled with an orthotropic Hookean elastic model. A rigorous experimental protocol— encompassing uniaxial compression, cyclic compression, and shear tests—was developed to calibrate constitutive parameters, including directional elastic moduli, yield strengths, and plastic Poisson's ratios. The parameterized model was validated through compression tests on specimens oriented in non-principal crystallographic directions ([0 1 1], [012], [021], [1 1 1], [112], [221]), demonstrating predictive errors below 10.5% for elastic modulus and 9.9% for yield strength. This work bridges the critical gap between homogenized constitutive theory and the manufacturing realities of architected cellular materials.