Eddy Current for Detecting Second Layer Cracks Under Installed Fasteners
The detection of second layer Cracks Under Fasteners (CUF) persists as an Air Force Logistics need. This work seeks to extend technology developed for detecting cracks in aluminum alloy substructure below graphite-epoxy skins, to structures with an aluminum first layer. Improvements to the design of...
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| creator | Sheppard, William R |
| description | The detection of second layer Cracks Under Fasteners (CUF) persists as an Air Force Logistics need. This work seeks to extend technology developed for detecting cracks in aluminum alloy substructure below graphite-epoxy skins, to structures with an aluminum first layer. Improvements to the design of the Northrop Low Frequency Eddy Current Array (LFECA) system are identified to improve sensitivity to CUFs in aluminum-over-aluminum structures. The probe core shape, dimensions, and coil configurations were optimized for detection with installed fasteners and metallic skin. A multiparameter analysis algorithm is applied to enable flaw discrimination from centering variations, edge responses and other sources of noise. The study also quantifies the capabilities and limitations of the LFECA system. Eddy current, Low frequency eddy current, Cracks, CUFs, Nondestructive Evaluation (NDE). |
| format | Report |
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This work seeks to extend technology developed for detecting cracks in aluminum alloy substructure below graphite-epoxy skins, to structures with an aluminum first layer. Improvements to the design of the Northrop Low Frequency Eddy Current Array (LFECA) system are identified to improve sensitivity to CUFs in aluminum-over-aluminum structures. The probe core shape, dimensions, and coil configurations were optimized for detection with installed fasteners and metallic skin. A multiparameter analysis algorithm is applied to enable flaw discrimination from centering variations, edge responses and other sources of noise. The study also quantifies the capabilities and limitations of the LFECA system. Eddy current, Low frequency eddy current, Cracks, CUFs, Nondestructive Evaluation (NDE).</description><language>eng</language><subject>AIR FORCE ; ALGORITHMS ; ALUMINUM ALLOYS ; Attack and Fighter Aircraft ; COILS ; CONFIGURATIONS ; CRACKS ; DEFECTS(MATERIALS) ; EDDY CURRENTS ; Electricity and Magnetism ; F/A-18 AIRCRAFT ; FASTENINGS ; FATIGUE(MECHANICS) ; FIGHTER AIRCRAFT ; GRAPHITE EPOXY COMPOSITES ; LOGISTICS ; LOW FREQUENCY ; MAGNETIC FIELDS ; MILITARY AIRCRAFT ; NOISE ; NONDESTRUCTIVE TESTING ; PE62102F ; PROBES ; SKIN(STRUCTURAL) ; WUWL24180252</subject><creationdate>1994</creationdate><rights>Approved for public release; distribution is unlimited.</rights><oa>free_for_read</oa><woscitedreferencessubscribed>false</woscitedreferencessubscribed></display><links><openurl>$$Topenurl_article</openurl><openurlfulltext>$$Topenurlfull_article</openurlfulltext><thumbnail>$$Tsyndetics_thumb_exl</thumbnail><link.rule.ids>230,776,881,27544,27545</link.rule.ids><linktorsrc>$$Uhttps://apps.dtic.mil/sti/citations/ADA282412$$EView_record_in_DTIC$$FView_record_in_$$GDTIC$$Hfree_for_read</linktorsrc></links><search><creatorcontrib>Sheppard, William R</creatorcontrib><creatorcontrib>NORTHROP CORP PICO RIVERA CA B-2 DIV</creatorcontrib><title>Eddy Current for Detecting Second Layer Cracks Under Installed Fasteners</title><description>The detection of second layer Cracks Under Fasteners (CUF) persists as an Air Force Logistics need. This work seeks to extend technology developed for detecting cracks in aluminum alloy substructure below graphite-epoxy skins, to structures with an aluminum first layer. Improvements to the design of the Northrop Low Frequency Eddy Current Array (LFECA) system are identified to improve sensitivity to CUFs in aluminum-over-aluminum structures. The probe core shape, dimensions, and coil configurations were optimized for detection with installed fasteners and metallic skin. A multiparameter analysis algorithm is applied to enable flaw discrimination from centering variations, edge responses and other sources of noise. The study also quantifies the capabilities and limitations of the LFECA system. Eddy current, Low frequency eddy current, Cracks, CUFs, Nondestructive Evaluation (NDE).</description><subject>AIR FORCE</subject><subject>ALGORITHMS</subject><subject>ALUMINUM ALLOYS</subject><subject>Attack and Fighter Aircraft</subject><subject>COILS</subject><subject>CONFIGURATIONS</subject><subject>CRACKS</subject><subject>DEFECTS(MATERIALS)</subject><subject>EDDY CURRENTS</subject><subject>Electricity and Magnetism</subject><subject>F/A-18 AIRCRAFT</subject><subject>FASTENINGS</subject><subject>FATIGUE(MECHANICS)</subject><subject>FIGHTER AIRCRAFT</subject><subject>GRAPHITE EPOXY COMPOSITES</subject><subject>LOGISTICS</subject><subject>LOW FREQUENCY</subject><subject>MAGNETIC FIELDS</subject><subject>MILITARY AIRCRAFT</subject><subject>NOISE</subject><subject>NONDESTRUCTIVE TESTING</subject><subject>PE62102F</subject><subject>PROBES</subject><subject>SKIN(STRUCTURAL)</subject><subject>WUWL24180252</subject><fulltext>true</fulltext><rsrctype>report</rsrctype><creationdate>1994</creationdate><recordtype>report</recordtype><sourceid>1RU</sourceid><recordid>eNrjZPBwTUmpVHAuLSpKzStRSMsvUnBJLUlNLsnMS1cITk3Oz0tR8EmsTC1ScC5KTM4uVgjNSwFyPPOKSxJzclJTFNwSi0tS81KLinkYWNMSc4pTeaE0N4OMm2uIs4duSklmcnwx0MDUknhHF0cjCyMTQyNjAtIAP6IwsQ</recordid><startdate>199404</startdate><enddate>199404</enddate><creator>Sheppard, William R</creator><scope>1RU</scope><scope>BHM</scope></search><sort><creationdate>199404</creationdate><title>Eddy Current for Detecting Second Layer Cracks Under Installed Fasteners</title><author>Sheppard, William R</author></sort><facets><frbrtype>5</frbrtype><frbrgroupid>cdi_FETCH-dtic_stinet_ADA2824123</frbrgroupid><rsrctype>reports</rsrctype><prefilter>reports</prefilter><language>eng</language><creationdate>1994</creationdate><topic>AIR FORCE</topic><topic>ALGORITHMS</topic><topic>ALUMINUM ALLOYS</topic><topic>Attack and Fighter Aircraft</topic><topic>COILS</topic><topic>CONFIGURATIONS</topic><topic>CRACKS</topic><topic>DEFECTS(MATERIALS)</topic><topic>EDDY CURRENTS</topic><topic>Electricity and Magnetism</topic><topic>F/A-18 AIRCRAFT</topic><topic>FASTENINGS</topic><topic>FATIGUE(MECHANICS)</topic><topic>FIGHTER AIRCRAFT</topic><topic>GRAPHITE EPOXY COMPOSITES</topic><topic>LOGISTICS</topic><topic>LOW FREQUENCY</topic><topic>MAGNETIC FIELDS</topic><topic>MILITARY AIRCRAFT</topic><topic>NOISE</topic><topic>NONDESTRUCTIVE TESTING</topic><topic>PE62102F</topic><topic>PROBES</topic><topic>SKIN(STRUCTURAL)</topic><topic>WUWL24180252</topic><toplevel>online_resources</toplevel><creatorcontrib>Sheppard, William R</creatorcontrib><creatorcontrib>NORTHROP CORP PICO RIVERA CA B-2 DIV</creatorcontrib><collection>DTIC Technical Reports</collection><collection>DTIC STINET</collection></facets><delivery><delcategory>Remote Search Resource</delcategory><fulltext>fulltext_linktorsrc</fulltext></delivery><addata><au>Sheppard, William R</au><aucorp>NORTHROP CORP PICO RIVERA CA B-2 DIV</aucorp><format>book</format><genre>unknown</genre><ristype>RPRT</ristype><btitle>Eddy Current for Detecting Second Layer Cracks Under Installed Fasteners</btitle><date>1994-04</date><risdate>1994</risdate><abstract>The detection of second layer Cracks Under Fasteners (CUF) persists as an Air Force Logistics need. This work seeks to extend technology developed for detecting cracks in aluminum alloy substructure below graphite-epoxy skins, to structures with an aluminum first layer. Improvements to the design of the Northrop Low Frequency Eddy Current Array (LFECA) system are identified to improve sensitivity to CUFs in aluminum-over-aluminum structures. The probe core shape, dimensions, and coil configurations were optimized for detection with installed fasteners and metallic skin. A multiparameter analysis algorithm is applied to enable flaw discrimination from centering variations, edge responses and other sources of noise. The study also quantifies the capabilities and limitations of the LFECA system. Eddy current, Low frequency eddy current, Cracks, CUFs, Nondestructive Evaluation (NDE).</abstract><oa>free_for_read</oa></addata></record> |
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| source | DTIC Technical Reports |
| subjects | AIR FORCE ALGORITHMS ALUMINUM ALLOYS Attack and Fighter Aircraft COILS CONFIGURATIONS CRACKS DEFECTS(MATERIALS) EDDY CURRENTS Electricity and Magnetism F/A-18 AIRCRAFT FASTENINGS FATIGUE(MECHANICS) FIGHTER AIRCRAFT GRAPHITE EPOXY COMPOSITES LOGISTICS LOW FREQUENCY MAGNETIC FIELDS MILITARY AIRCRAFT NOISE NONDESTRUCTIVE TESTING PE62102F PROBES SKIN(STRUCTURAL) WUWL24180252 |
| title | Eddy Current for Detecting Second Layer Cracks Under Installed Fasteners |
| url | https://sfx.bib-bvb.de/sfx_tum?ctx_ver=Z39.88-2004&ctx_enc=info:ofi/enc:UTF-8&ctx_tim=2025-02-12T15%3A29%3A35IST&url_ver=Z39.88-2004&url_ctx_fmt=infofi/fmt:kev:mtx:ctx&rfr_id=info:sid/primo.exlibrisgroup.com:primo3-Article-dtic_1RU&rft_val_fmt=info:ofi/fmt:kev:mtx:book&rft.genre=unknown&rft.btitle=Eddy%20Current%20for%20Detecting%20Second%20Layer%20Cracks%20Under%20Installed%20Fasteners&rft.au=Sheppard,%20William%20R&rft.aucorp=NORTHROP%20CORP%20PICO%20RIVERA%20CA%20B-2%20DIV&rft.date=1994-04&rft_id=info:doi/&rft_dat=%3Cdtic_1RU%3EADA282412%3C/dtic_1RU%3E%3Curl%3E%3C/url%3E&disable_directlink=true&sfx.directlink=off&sfx.report_link=0&rft_id=info:oai/&rft_id=info:pmid/&rfr_iscdi=true |