Investigating the Effects of Different Geometries Used In Flexural Hinges on Their Fatigue Life

A rigid link mechanism can be converted into a compliant mechanism by replacing rigid joints with flexural hinges. In most of the compliant mechanism, it is found that the compliant mechanism fails at flexural hinges due to cyclic load. To minimize the failure i. e. increasing the fatigue life of these flexural hinges, different configurations of geometries have been tried. This paper presents a methodology for calculating the fatigue life of flexural hinges by using analytical approach. This paper also discusses different geometries available for design of flexural hinges like circular, rectangular and parabolic along with the effect of geometry on the fatigue life cycle of the flexure hinge. The design flexural hinge is done for compliant mechanisms used for displacement amplification applications. Finite element analysis has been carried out to validate the fatigue life calculated by analytical approach and results are discussed in this paper