Flexible hinge is widely used in precision engineering

MEMS

intelligent sensors and other fields

whose fatigue failure is likely to occur due to periodic load. In this paper

the fatigue characteristics of second-order Bezier curved flexible hinges were studied. Stress concentration factor formulation was obtained through fitting based on finite element simulation data. Fatigue life prediction model of the flexible hinge was established using the nominal stress method. Fatigue experiment was carried out on a fatigue test system. The stiffness degradation curve and S-N curve of flexible hinges under different stress levels were obtained. And the design S-N curve model accounting for confidence level and reliability was designed adopting the one-side lower-bound tolerance limit method. Comparison shows that the maximum error between the logarithmic fatigue life predicted value and the experimental results is 15.8%

which illustrates the effectiveness of the life prediction model.