Fatigue Life Assessment of the Inflective Arm Roller in High-voltage Switch Spring Operating Mechanism

Spring operating mechanism (SOM) failures are the main cause of circuit breaker failures, and the reliability issues of widely used SOM have always been a challenging research topic in the high-voltage circuit field. This paper proposes a combined approach of simulation and experimentation, taking a spring operating mechanism currently under development by a certain company as an example. The objective is to address the reliability issues by employing an integrated experimental and simulation method and conducting a fatigue life assessment of the vulnerable component, the inflective arm roller, using a modal stress recovery-based approach. On one hand, the stiffness, mass, and damping characteristics of the structure are obtained through modal analysis of the finite element model, which provides the structural stress distribution. On the other hand, by establishing a coupled dynamic model of the entire spring operating mechanism and validating it through experiments, the load spectra of the roller during the closing process are obtained, effectively reducing the uncertainty in fatigue life prediction and fatigue test costs while improving the reliability of spring operating mechanisms.