Reliability modeling for competing failure processes considering degradation rate variation under cumulative shock |
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Authors: | Zhihua Wang Shihao Cao Wenbo Li Chengrui Liu Jingjing Mu |
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Affiliation: | 1. School of Aeronautic Science and Engineering, Beihang University, Beijing, 100191 China;2. Beijing Institute of Control Engineering, Beijing, 100094 China;3. China Aerospace Science and Technology Corporation, Beijing, 100094 China |
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Abstract: | Most systems experience both random shocks (hard failure) and performance degradation (soft failure) during service span, and the dependence of the two competing failure processes has become a key issue. In this study, a novel dependent competing failure processes (DCFPs) model with a varying degradation rate is proposed. The comprehensive impact of random shocks, especially the effect of cumulative shock, is reasonably considered. Specifically, a shock will cause an abrupt degradation damage, and when the cumulative shock reaches a predefined threshold, the degradation rate will change. An analytical reliability solution is derived under the concept of first hitting time (FHT). Besides, a one-step maximum likelihood estimation method is established by constructing a comprehensive likelihood function. Finally, the reasonability of the closed form reliability solution and the feasibility and effectiveness of the proposed DCFPs modeling methodology are demonstrated by a comparative simulation study. |
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Keywords: | analytic reliability solution dependent competing failure processes one-step parameter estimation variation of degradation rate Wiener degradation process |
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