A generic approximation model for analyzing large nonlinear deflection of beam-based flexure joints

This paper introduces a semi-analytic model that provides a simple and generic solution for approximating the large nonlinear deflection of any beam-based flexure configuration, i.e., a beam-based flexure coupled with a rigid-link. The accuracy and robustness of the proposed model is ensured by considering two crucial factors while adopting the principle of using a torsional spring to represent the stiffness of a beam-based flexure joint. The first factor is the parasitic shifting of the ‘pivot’ joint of a beam-based flexure joint during large deflection, while the second factor is the changing angular stiffness of the torsional spring. Comparisons with past theoretical models show that the semi-analytic model can accurately approximate these two factors. Consequently, this proposed model offers an accurate approximation on the large nonlinear deflections of any beam-based flexure configuration with deviations ranging from 0.1% to 5.6% when compared to the experimental results.