Analytical solutions for nonlinear deflections of corner-fillet leaf-springs

Leaf-springs are used in various applications such as micro-grippers, nano-positioning mechanisms, and flexible pivots to provide a large range of rotation or translational motion. The nonlinearities caused by axial loads in some intermediate or large deflection applications pose new challenges for the design of leaf springs with variable thickness. Corner-fillet leaf-springs (CFLSs) are the most commonly used flexible members in compliant mechanisms to reduce maximum stress. The nonlinear deflection of CFLS is modeled to explore a convenient design method for low-stress and intermediate-range applications. The load-deflection relationship of fixed-guided CFLS is formulated for the compliant parallelogram mechanisms. The predicted results of proposed methods have good agreement with nonlinear finite element results and experimental results. A CFLS-based design is provided to illustrate the implementation of the proposed model, which reduces the maximum stress of mechanism by 33% as compared to that of the beam-based design.