A uniaxial hysteretic superelastic constitutive model applied to additive manufactured lattices

Abstract

Lattice materials with superelastic properties offer great potential for engineering applications, as they are able to undergo large deformations while ensuring the reversibility of the deformations due to stress-induced phase transformation. Adequate prediction of the mechanical response of lattice materials requires models that properly capture the deformation mechanisms of the internal architecture and the material response of the parent material. To analyze large-scale lattices by means of the finite element method, numerical efficiency becomes crucial. For this purpose, we propose a simple approach relying on beam-based modeling in combination with a uniaxial superelastic constitutive material model. The latter is based on polynomial functions, which make it easy to take customer-based material data into account being especially important for additive manufactured materials. To verify our constitutive model, a comparison with a well-established standard model is performed. The capabilities of the beam-based model to predict the mechanical response of lattice materials are evaluated by the comparison to high-fidelity models using continuum elements. We show that beam-based modeling is able to capture the governing deformation mechanisms of the investigated lattices and that our constitutive model is able to capture the smooth stress–strain response of the experimental data that are not available to the standard model.