Gearbox device failure mode criticality analysis based on support vector machine

A method which integrates expert evaluation method and support vector machine (SVM) method is introduced for failure mode criticality analysis (FMCA) about the gearbox device. An expert evaluation standard is built by using expert evaluation method. The experts make scores about the gearbox failure mode. In order to overcome the subjectivity of expert evaluation method, we use SVM method to make a comprehensive prediction about the scores. According to the comprehensive prediction evaluation results, the FMCA of the gearbox device can be obtained. The analysis shows that the method used in this paper not only can effectively solve the problem which is unable to get specific failure rate in the qualitative analysis, but also can solve the problem which needs lots of data in the quantitative analysis.     

Welded joint fatigue reliability analysis on bogie frame of high-speed electric multiple unit

A new method for welded joint fatigue reliability analysis on bogie frame of high-speed electric multiple unit (EMU) is proposed according to the International Union of Railways (UIC) standard, the Britain Standard Institute (BSI) standard and the Miner rule. Firstly, the fatigue calculation condition is loaded according to the UIC standard. The welded joint damage ratio is calculated by the BSI standard. Fatigue reliability analysis is conducted for a typical welded joint based on probabilistic design system (PDS) module in software ANSYS 14.0. In the system, the automatic program is prepared by ANSYS parametric design language (APDL) to calculate the welded joint fatigue damage ratio. Meantime, the relationship between the input variables and the output response is fitted by the response surface (RS) method. Then, the RS method is improved by the orthogonal design. Specifically, the selecting process optimization for the RS method based on the orthogonal design is conducted to improve the fitting efficiency of the RS method. Finally, a program of the automatic analysis documents is generated by Microsoft foundation class (MFC) technique. Through the self-defined interface, the researchers can easily import the automatic generation of the orthogonal table into the PDS module and analyze the fatigue reliability. Results show that the improved RS method can better fit the RS which covers the sample area, and the distribution law agrees well with the actual situation. At the same time, the improved RS method reduces the calculation time.