A Comprehensive Failure Risk Assessment Method of Machining Center Component Based on Topology Analysis

The risk assessment of the failure mode of the traditional machining center component rarely considers the topological characteristics of the system and the influence of propagation risks, which makes the failure risk assessment results biased. Therefore, this paper proposes a comprehensive failure risk assessment method of a machining center component based on topology analysis. On the basis of failure mode and cause analysis, considering the correlation of failure modes, Analytic Network Process (ANP) is used to calculate the influence degree of failure modes, and it is combined with component failure mode frequency ratio and failure rate function to calculate independent failure risk. The ANP model of the machining center is transformed into a topological model, and the centrality measurement of network theory is used to analyze the topology of the machining center. The weight of the topological structure index is measured by subjective and objective weighting methods, and then the importance degree of the machining center component is calculated. In this paper, the coupling degree function is introduced to calculate the importance of the connection edge, which is combined with the failure probability to calculate the failure propagation influence degree, and the component propagation failure risk is calculated based on this. Finally, the independent failure risk and the propagation failure risk of the component are integrated to realize the failure risk assessment of the component. Taking a certain type of machining center as an example to illustrate the application, compared with the traditional assessment method, the effectiveness and advancement of the method proposed in this paper have been verified.

Reliability analysis of network systems subject to probabilistic propagation failures and failure isolation effects

In this article, the reliability of network systems subject to probabilistic propagation failure and failure isolation effects is considered. Probabilistic propagation failure is the failure of some components in a system, which will cause other components to fail with certain probabilities. Probabilistic propagation failure exists in various network systems, such as computing network system and nuclear power generating network system. Failure isolation means that the failure of a trigger component will lead to its corresponding dependent components being isolated from the network system. Since the failure isolation effect is activated only when the failure of trigger components occurs before the occurrence of probabilistic propagation failure, there exists a competing failure in the time domain between the failure of a trigger component and the components with probabilistic propagation failure effect. If a trigger component failure occurs first, the system is insensitive to any failures of components being isolated. In this article, a combinatorial method based on binary decision diagram is proposed to analyze the reliability of the network systems subject to probabilistic propagation failure and failure isolation effects. The method can be applied to any network system and any type of lifetime distribution of the system components. As an example, a wide area network system is analyzed. Some numerical results about reliability indexes are provided to verify the feasibility and accuracy of the proposed method.