漏磁检测若干关键技术的研究

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1、中国科学技术大学博士学位论文漏磁检测若干关键技术的研究姓名：张勇申请学位级别：博士专业：信号与信息处理指导教师：叶中付20070401中田科学技术大学博士学位论文际应用意义。然后，本文总结了磁偶极子应用在漏磁场分析中的研究成果，提出了一种利用漏磁信号分步重构缺陷形状的方法，并对半圆形、三角形、矩形这三种常见的缺陷形状举例进行说明。以上三个例子可以说明，本文提出的逐次逼近法重构缺陷的形状取得了较好的效果，与其它方法相比，有计算量小，重构方法简单的优点。在本文最后针对目前漏磁检测的研究现状，提出了进一步的研究方向。关键词：无损检测，漏磁检测，干扰抵消，信道均

2、衡，磁偶极子，缺陷重构中胃科学技术大学博士学位论文Abstr，dResearchonsomeKeyTechnologiesofMFLInspectionAbstractBased011thefactthatsomephysicquantumwouldbechangedbecauseofexistingdefects．nondestructivetestingoqna3coulddefectthedefects．NDTplaysaimportantroleofqualitycontrollingandsavinglaWmaterialsandimprove

3、productivityinindustrymanufacture．NDTisalsoaimportantinspectionmeansfortheequipment．Asoneofthemostimportant,fastestandcheapestnondesmlctivetestingmethods，Magneticfluxleakagetechnologycouldbeappliedininspectionferromagneticmaterials．MFLisalsothemostcommoIllyusedinnondestructivetes

4、tinganditcouldfindthemajorityofdiscontinuities．Themainresearchcontentsinthispaperinclude：First,theundetectableareainseamlesspipelineQipelineheaas)isusuallyinspectedbymagneticparticles，butmagneticparticlesmerelyinspectthedefectnearpipelines’outersurfaec．Theparticleindicationofdefe

5、ctsisusuallyobservedbyeye，andSOthetestingreliabilityhasahigllhunmafactorinfluencedependingontheoperator．Forthereasonofequipmentitself,MFLinspectionequipmentcouldn’timpemthepipelineheads。whicharcregardedasanundetectablea嘲inMFLexamination．Inthispaperweattempttou∞anewmethodbasedOilM

6、FLt0inspectpipelineheads．Weintroducetheideaofleadingpipeline，andexpatiatethemethodofseparatingtheMFLsignalofdefectnoarpipelineheads．Thedifferencebetweenreferencesignalandartificialflawsignalcanbeextractedproperlybyusingcorrelationcanceling．TheexperimentsshowthatitispossibleforMFL

7、technologytoinspectthetubehead，andimprovetheinspectionefficiency．Then，influencedbythelift—offvaluebetweenthepipelineandcoilSenSOrS，thevariouspropertiesofdeetroniccomponentandthedifferentlocationofcoilsensor,iii中田科学技术大学博士学位论文Abstracttheoutputsi萨aI’samplitudeandphaseofeachchannelar

8、edifferentdespitethesalYleflawinMFLinspe