Impact of Geometrical Parameters on Fatigue Life Cycle of Compliant Mechanism

Abstract

Compliant mechanisms, which derive motion through the elastic deformation of flexible members, offer distinct advantages over traditional mechanisms, including reduced part count, enhanced reliability, and smooth, frictionless operation. However, their fatigue life is a critical design concern due to the continuous cyclic stresses endured during operation. The fatigue performance of these mechanisms is strongly influenced by a combination of material properties, geometrical design, and loading conditions. Among these, geometrical parameters—particularly the radius of curvature—play a crucial role in determining stress concentration and overall durability.This study focuses on analyzing the impact of the radius of curvature on the fatigue life of compliant mechanisms using Finite Element Analysis (FEA). Four different conFigureurations of square and circular motion stages with varying curvature radii were evaluated under constant loading conditions. The analysis considered key parameters such as damage factor, safety factor, and fatigue life cycles. Results indicate that increasing the radius of curvature significantly improves fatigue resistance by distributing stress more evenly and reducing critical stress concentrations.The findings suggest that appropriate geometric optimization, especially in curved beam regions, can substantially enhance the life span and safety of compliant mechanisms without compromising their function. These insights are particularly beneficial for the design of mechanisms in applications requiring high precision and longevity, such as biomedical devices, micro-positioning systems, and additive manufacturing equipment. This research contributes valuable design guidelines for enhancing the fatigue performance and operational reliability of compliant mechanisms.