Community Clustering Algorithms and Its Application in Machine Fault Diagnosis

The complex network, as a method for analyzing nonlinear and non-stationary signals, overcomes the shortcomings of traditional time–frequency analysis methods and proves its effectiveness in mechanical fault diagnosis. Community clustering, as one of them, has made great progress in recent years. However, the existing community clustering algorithms have the disadvantages of lacking significant global extreme value and huge search space. Therefore, a Fast Newman algorithm based on reliability judgment is proposed. Starting from the community structure characteristics of the complex network, with the fault sample as a network node, the relationship between the samples as a connected edge, and a complex network model of fault data is established. Clusters in troubleshooting are transformed into community structure discovery in the network. First, the initial division of the community is obtained by measuring the distance between the samples. Then, the modularity index of the network is used as a standard function of the community division, and the bottom-up community merger is performed. The local edge density index is used for reliability determination before each combination to achieve global optimization, and the network block structure is the most obvious. Finally, with all data being merged into one community, the optimal division of the community structure is obtained while accurate community clustering and fault diagnosis are realized. The benchmark graphs for testing community detection (LFR standard test network) and different fault data of rolling bearings under multiple operating conditions are applied to verify the effectiveness of this method, and the experiment results prove that the modified Fast Newman algorithm has a better clustering effect and a higher correct rate than the original one. Compared with K-means clustering and fuzzy clustering, the modified Fast Newman algorithm achieves higher performance in fault diagnosis of rolling bearings under multiple operating conditions.