多界面超聲脫粘檢測的方法研究及信號處理.pdf

1、華北工學院碩士學位論文多界面超聲脫粘檢測的方法研究及信號處理姓名：陳友興申請學位級別：碩士專業(yè)：測試計量技術及儀器指導教師：王召巴20040316華北工學院學位論文MethodSignalProcessingfUltrasonicTestingofMultilayeredAdhesiveInterfaceCHENYouxingWANGZhaobaAbstractUltrasonictestingoneofthecommonnondest

2、ructivetestingtechnologiesiswidelyusedinaerospacenuclearpetroleumindustryotherfieldsfdefectsintheadhesivestructure.Itisdifficulttodetectinterfacedebondintheadhesivemultilayeredsteelrubberstructurethroughthecommonultrason

3、ictestingduetotheconsiderableacousticimpedancedifferencesofbetweenthesteeltherubber.Theultrasonictestingsignalprocessingfbondeddefectsinthestructureofflexiblejointofthesolidrocketmotsarestudied.theLambWavemethodtheLongit

4、udinalWavemethodareusedintheultrasonictesting.Thetransmissionruleofthelambwaveinthestructureoftheflexiblejointisdiscussedtheultrasonicpulseechoisanalyzedinthetimefieldfrequencyfield.TheConstantseparatemethodtheAdaptivese

5、paratemethodbasedontheaboveultrasonicprincipleareusedtoseparateeachinterfaceechointheultrasonicpulseecho.ThefeatureoftheeachultrasonicpulseechoisgainedthroughthewavelettransfmationisidentifiedthroughBPneuralwk.TheLongitu

6、dinalWavemethodftestingthestructureisalsodiscussed.Itisfoundthatthebisensmethodcandeterminewhetherthestructurehasinterfacedebond.Thentheadaptivefilteringisadoptedinthesignalprocessingftheechothroughsinglesens.Basedonthea

7、boveresultsthefeatureofeachinterfaceechoisgained.ItisshownbyexperimentsthattheLambWavemethodtheLongitudinalWavemethodarebothcapableofdetectingtheadhesivestateofthestructure.Thedetectionofthestructurebecomesmecomprehensiv