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Quantitative Detection Of Multi Parameter Cracks In Ferromagnetic Materials

Posted on:2018-11-07Degree:MasterType:Thesis
Country:ChinaCandidate:H JiangFull Text:PDF
GTID:2321330536961437Subject:Mechanical design and theory
Abstract/Summary:PDF Full Text Request
At present,the quantitative nondestructive testing of the crack is the key problem to evaluate the residual life of the remanufacturing blank.In this paper,a new method based on metal magnetic memory,ultrasonic and eddy current is proposed.The method can detect the location and depth of cracks accurately.The new way can help improve the remanufacturing blank residual life assessment accuracy,to improve the quality and reliability of remanufacturing parts.In this paper,the mechanism of metal magnetic memory,eddy current and ultrasonic wave is systematically analyzed.The three kinds of multi parameter detection system of the sensor are built successfully,which realizes the automation of the testing process.The corresponding feature extraction of the signal waveform is obtained,and the identification parameters of the quantitative information are constructed.Based onrecognition characteristic parameter,fusion method of fuzzy overlap region is proposed and the model is construct.The main work is as follows:(1)The present situation of compound detection is analyzed.The mechanism of metal magnetic memory,ultrasonic and eddy currentis studied on,and some experiments have been done to verify the results.(2)The multi parameter detection method of metal magnetic memory,ultrasonic and eddy current sensor is proposed,and a multi parameter detection system is built.The system can display the position of the detector in real time and accurately locate the position of the crack,which simplify the operation process and reduce the technical threshold.(3)The characteristics of the metal magnetic memory,ultrasonic and eddy current signals are extracted,and the characteristic quantity of the crack depth can be constructed.And the standard prefabricated crack specimen was collected and extracted to construct the standard evidence for the next data fusion(4)In order to further approximatethe true value of crack,the depth of fuzzy overlap region is subdivided for the three regions.The application of Manhattan confidence distribution function and D-S evidence theory is to obtain a more accurate crack depth interval.(5)Verify the correctness of the solution proposed in this paper by comparing error between the experimental values and the actual values.
Keywords/Search Tags:Multi parameter, metal magnetic memory, feature extraction, D-S data theory
PDF Full Text Request
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