# A Comprehensive Failure Risk Assessment Method of
###### Abstract  
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. analysis method (FMEA) [4; 5; 6] and failure mode effects and criticality analysis method (FMECA) [7; 8; 9]. The HAZOP method is used to determine the cause of this deviation by analyzing abnormal changes in process parameters during the production process and then analyze what measures should be taken. The expert investigation method is a method for judging and predicting the risk trend of the research object based on the expert's knowledge and experience. FMEA and FMECA identify the failure mode and evaluate the consequences or effects of the failure mode to determine the impact of the failure risk and countermeasures. The qualitative assessment method has the advantages of simple operation and easy to master; thus, it is often preferred. However, the results of this assessment method rely too much on the experience of the evaluator. When the factors considered by the evaluator are not comprehensive, unsystematic, or unable to reflect the status of the system, the assessment results are often inaccurate. Quantitative risk assessment methods mainly quantify the occurrence probability and impact of security incidents and then quantitatively describe the risk level of the assessment object. The current quantitative risk assessment methods are mostly based on fault tree analysis (FTA) [10; 11; 12], event tree analysis (ETA) [13; 14; 15], and criticality analysis (CA) [16; 17]. The FTA method obtains the minimum cut set of the fault tree through calculation, finds out the weak links in the system, and develops appropriate risk control strategies for the weak links. ETA is based on the time and causal sequence of the occurrence of events, starting from the initial event and then identifying the intermediate events related to it until finding the resulting event, and conducting risk assessment on it. CA divides the risk severity and possibility of the research object into corresponding grades according to characteristics, forms a risk assessment matrix, and assigns a certain weighted value to measure the risk. The quantification of risk by quantitative analysis method promotes the close connection between operation mechanism and operation norms. The analysis goals are more specific and accurate, providing a reliable reference for the reasonable formulation of emergency plan.