A multi-state degradation reliability model based on continuous time Markov stochastic process and its application
Traditional two-state reliability evaluation method cannot reflect the multi-state variation characteristics of performance degradation of complex systems.To evaluate the dynamic and changeable characteristics of the reliability of degradation process of mechanical system,a dynamic system reliability evaluation method based on multi-state degradation model was proposed in the present study.By using the theory of continuous-time Markov stochastic process,the multi-state degradation stochastic process model of system performance was established based on the minimum repair strategy.Then,the model was solved by the Laplace transformation,the general time dependent probability expressions of each system state was obtained,and the time dependent reliability indices of system was derived.Thus,the reliability dynamic change characteristics of the multi-state degradation process of system was obtained.Taking the fatigue performance degradation process of a vehicle sub-frame as study object,the multi-state degradation reliability evaluation model with respect to the fatigue performance of the sub-frame was established.Data-driven by the fatigue test data,the model calculation results of reliability indices were nearly the same as those of actual test.The errors were less than 3%,therefore the effectiveness of the proposed model was verified.Therefore effective simulation and dynamic evaluation of the fatigue performance deterioration process of the sub-frame was realized.The proposed method also provided a reference for the research on the reliability evaluation of multi-state degradation process of complex mechanical systems.
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