A Reliability Allocation Method Considering Failure Correlation Based on Vine Copula

Abstract

In order to consider the influence of different failure correlation between the components of the system on system reliability allocation results, the factors affecting the system reliability allocation is divided into direct and indirect subcategories. The relative value of the reliability allocation weight of the components is proposed as a direct influence factor of the complexity and the failure criticality. The working environment, technical level, improvement cost and so on are classified as indirect factors. The relative dispersion is introduced to describe the failure correlation of system components, and is put forward of calculating the complexity and criticality. Based on the Vine Copula function, the reliability allocation model of the series system considering the failure correlation among the components is established. Finally, taking a certain type of CNC spindle system as an example, a comparative analysis of the system reliability allocation results in two cases without considering the correlation and considering the correlation is made. The results show that without considering the correlation the allocation results are conservative, which increased product development costs. The system reliability allocation model based on the Vine Copula function can take into account the different failure correlations among the components. The result is more reasonable than the traditional multivariate Copula function.