Nonlinear Deformation Analysis of Superelastic Flexure Hinges

The motion capability of a flexure hinge made of shape memory alloy (SMA) can be greatly improved because of the material’s superelasticity. In this paper, the nonlinear deformation characteristics of a superelastic flexure hinge are analyzed. The flexure hinge is considered as a non-prismatic cantilever beam subjected to a combined load at the free end. Superelastic behavior of the SMA is represented by Auricchio’s constitutive model. Govern equations of the large deformation superelastic flexure hinge are derived by using the Bernoulli-Euler beam theory and solved numerically. Based on the static deformation model, the rotation capacity, the stiffness characteristic and the rotation error of the flexure hinge are discussed respectively. Numerical examples compared with Finite Element analysis (FEA) show the accuracy of the proposed methodology.