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Refined composite multiscale fuzzy entropy: Localized defect detection of rolling element bearing
Yongjian Li,Bingrong Miao,Weihua Zhang,Peng Chen,Jihua Liu,Xiaoliang Jiang 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.1
We proposed an appealing method based on refined composite multiscale fuzzy entropy (RCMFE), infinite feature selection (Inf-FS) algorithm, and support vector machine (SVM) for implementing localized defect detection to keep the downtime and extended damage caused by incipient failure of bearing at a minimum. As a useful approach, multiscale fuzzy entropy (MFE) was utilized to measure the complexity and dynamic changes of signals. However, an inaccurate entropy value would be yielded with the increase of scale factor. Here, as an improvement version of MFE, the RCMFE was proposed to address the shortcomings in the case of short time series. For this novel method, we conducted a full investigation of the effects and robustness by comparing the proposed method with two other entropybased approaches using synthetic signals and real data. Results indicate that the proposed algorithm outperforms the other approaches in terms of reliability and stability. The RCMFE values of bearing signals from one healthy condition and seven fault states are calculated as diagnostic information. Moreover, an intelligent fault identification method was constructed by combining the Inf-FS algorithm and SVM classifier. Experimental results show the usefulness of the proposed strategy.
A reduced time-varying model for a long beam on elastic foundation under moving loads
Guiming Mei,Caijin Yang,Shulin Liang,Jiangwen Wang,Dong Zou,Weihua Zhang,Yunshi Zhao,Zhong Huang,Shuqi Song,Mengying Tan,Yao Cheng,Bingrong Miao 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.9
Dynamics of a long beam on the elastic foundation subjected to moving loads is studied in the present paper. The sliding window technique is used to dynamically truncate the long beam and a reduced time-varying beam system is obtained. The Hamilton’s principle is employed to establish the equations of motion of the reduced system. The variable separation method is adopted to solve dynamical responses of the reduced system. Examples of a long simply supported Timoshenko beam on the nonlinear foundation subjected to a single moving load and multiple loads are included. Numerical results of the reduced model compared with the ones obtained from the moving element model adapted in literature are carried out to show the validity and the good efficiency of the method proposed in the present paper.