Modeling and analysis of planar symmetric superelastic flexure hinges

Flexure hinges are frequently used in compliant mechanisms to obtain micro movements with high precision. In this paper, the planar symmetric superelastic flexure hinge is proposed. The motion capacity of the superelastic flexure hinge is significantly increased compared with conventional flexure hinges due to the distinguished features of the superelastic materials. The proposed flexure hinge is modeled by beam elements which consider the variation of the beam cross-section, and the geometric and material nonlinearities. Based on that model, the static responses of the planar symmetric superelastic flexure hinges with different notches are compared and analyzed. Both of the numerical calculation and the experiments indicate that the proposed methodology can accurately predict the deformation of the superelastic flexure hinges, and it also effectively decreases the calculation cost compared with FEA by ANSYS. In addition, three indexes are proposed and defined to evaluate the performance of the superelastic flexure hinge and the influence of the geometric parameters and the notch shapes on the performance of the hinge are also investigated.