This paper introduces the basic concept of stress-strength interference model in mechanical reliability analysis. The stress relaxation model, combined strength degradation model and reliability calculation model of cylindrical coil spring are given. The reliability and operation of the circuit breaker opening and closing spring are given. The number of times is correlated to investigate the phenomenon that the reliability of the energy storage spring decreases as the number of operations increases. Combined with the energy storage spring of a 126KV circuit breaker, according to the stress relaxation model, the stress relaxation related model considering the strength degradation and stress relaxation is established by considering the stress relaxation related factors in the reliability calculation model considering strength degradation. The change rule of the reliability of the energy storage spring of the circuit breaker opening and closing is realized.

Reliability; strength degradation; stress relaxation; circuit breaker