# A New Hybrid Dynamic FMECA with Decision-Making Methodology: A Case Study in an Agri-Food Company
## 2 Methodology  
In order to overcome the limitations previously explained, a new methodology to the rank the causes and predicts what the critical events are. In Table 1, the starting table of our method is presented:  
In Table 2, a list of the nomenclature used in this methodology is presented.  
* A case study carried out on a machine of an important Italian company in the agri-food sector is presented to evaluate the proposed mode's robustness.
* The paper is organised as follows: In Section 2, a brief report on the state-of-the-art FMECA is proposed, with particular attention to the developments proposed in  
\begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline
**Functional** & **Components** & **Failure Mode** & **Failure Cause** & **Effect** & **Occurrence** & **Severity** & **Detectability** & **Cost** \\ \hline \(U_{i}\) & C\({}_{j}\) & \(FM\) & CFL & \(E_{m}\) & \(X\) & \(X\) & \(X\) & \(X\) \\ \hline \hline \end{tabular}
\end{table}
Table 1: Problem formulation.  
\begin{table}
\begin{tabular}{c c} \hline \hline S & Severity \\ \hline O & Occurrence \\ \hline D & Detectability \\ \hline C & Cost \\ \hline I & Index referring to the alternatives \\ \hline J & Index referring to the criteria \\ \hline \(x_{ij}\) & Element of initial Decision matrix \\ \hline \(z_{ij}\) & Element of Entropy normalisation-matrix \\ \hline N & Alternative’s number \\ \hline M & Criteria’s number \\ \hline C\({}_{MP}\) & Cost of non-production \\ \hline C\({}_{bp}\) & Cost of production manpower \\ \hline C\({}_{hips}\) & The extraordinary cost of production manpower \\ \hline C\({}_{MDO}\) & Cost of maintenance manpower \\ \hline C\({}_{R}\) & Cost of spare parts \\ \hline \(E_{j}\) & Entropy of j-th criteria \\ \hline \(d_{j}\) & Degrees of variation \\ \hline \(W_{j(E)}\) & Weight of the j-th criteria by entropy method \\ \hline \(W_{j(BWM)}\) & Weight of the j-th criteria by Best Worst Method \\ \hline \(AV_{j}\) & Average value of Decision Matrix \\ \hline PDA & Positive distance to average \\ \hline NDA & Negative distance to average \\ \hline SP & Weighted sum of PDA for each alternative \\ \hline SN & Weighted sum of NDA for each alternative \\ \hline NSP & Normalised SP \\ \hline NSN & Normalise SN \\ \hline AS & Appraisal score \\ \hline \hline \end{tabular}
\end{table}
Table 2: Nomenclature table.  
conjunction with MCDM. In Section 3, the problem is defined generically, and the methodology is proposed. Section 4 describes the case study. Finally, the last section focuses on conclusions and proposals for future work developments.  
Each step of this proposed method is explained in detail in this section. Figure 1 represents the logical sequence of an operations flowchart to execute the EN-B-ED Dynamic FMECA correctly.  
Multidisciplinary Team Creation, Machine Breakdown into Functional Units and Identification of FMs and CFs  
The proposed methodology starts from a classical FMEA analysis with a multidisciplinary team of specialists who identify the critical areas of the system analysing them. The output of this analysis is the identification of the possible failure modes and the related causes and effects. Hence, the criteria that best describe the risk associated with FMs are defined, and the criterion for each possible cause of the fault is evaluated.