Modeling of superelastic auxetic structures of Ti–Zr base alloy

Abstract

The superelastic properties of a novel shape memory Ti–24Zr–10Nb–2Sn alloy were evaluated in two different auxetic geometrics embedded in an airfoil by the nonlinear finite element software Abaqus. In the first part, a constitutive model was developed to determine the phenomenology and mechanical response of shape memory alloy in a superelastic state. In the second part, a numerical model of re-entrant and chiral auxetic structures was developed. The beam modeling was selected due to its efficiency in contrast to the shell and 3D solid elements. The chiral structure (simple AAS and complex AAC) is accommodated within the airfoil providing flexibility and ability to withstand loads. A larger displacement with limited strain of the airfoil was observed in both conditions. Numerical results of auxetic structural elements were consistent with experimental results. This study explores the superelastic capability of novel shape memory alloys embedded with auxetic core lattice as an alternative for soft morphing airfoil. • Finite element modeling of auxetic structures were developed to simulate superelastic capacity of Ti–24Zr alloy. • Two-dimensional model of the Eppler 420 airfoil structure was developed and evaluated for external loading conditions. • A constitutive model was developed to determine the mechanical response of shape memory alloy in a superelastic state. • The maximum stress is proportional to the number of sub-cells in auxetic structures. • A larger displacement with limited strain of the airfoil was observed in simple AAS and complex AAC chiral structures.