ASTM_E_2582_-_07_2014.pdf

Designation:E258207(Reapproved 2014)Standard Practice forInfrared Flash Thermography of Composite Panels andRepair Patches Used in Aerospace Applications1This standard is issued under the fixed designation E2582;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the U.S.Department of Defense.1.Scope1.1 This practice describes a procedure for detecting sub-surface flaws in composite panels and repair patches usingFlash Thermography(FT),in which an infrared(IR)camera isused to detect anomalous cooling behavior of a sample surfaceafter it has been heated with a spatially uniform light pulsefrom a flash lamp array.1.2 This practice describes established FT test methods thatare currently used by industry,and have demonstrated utility inquality assurance of composite structures during post-manufacturing and in-service examinations.1.3 This practice has utility for testing of polymer compos-ite panels and repair patches containing,but not limited to,bismaleimide,epoxy,phenolic,poly(amideimide),polybenzimidazole,polyester(thermosettingandthermoplastic),poly(ether ether ketone),poly(ether imide),polyimide(thermosetting and thermoplastic),poly(phenylenesulfide),or polysulfone matrices;and alumina,aramid,boron,carbon,glass,quartz,or silicon carbide fibers.Typical as-fabricated geometries include uniaxial,cross ply and angle plylaminates;as well as honeycomb core sandwich core materials.1.4 This practice has utility for testing of ceramic matrixcomposite panels containing,but not limited to,silicon carbide,silicon nitride and carbon matrix and fibers.1.5 This practice applies to polymer or ceramic matrixcomposite structures with inspection surfaces that are suffi-ciently optically opaque to absorb incident light,and that havesufficient emissivity to allow monitoring of the surface tem-perature with an IR camera.Excessively thick samples,orsamples with low thermal diffusivities,require long acquisitionperiods and yield weak signals approaching background andnoise levels,and may be impractical for this technique.1.6 This practice applies to detection of flaws in a compositepanel or repair patch,or at the bonded interface between thepanel and a supporting sandwich core or solid substrate.It doesnot apply to discontinuities in the sandwich core,or at theinterface between the sandwich core and a second panel on thefar side of the core(with respect to the inspection apparatus).1.7 This practice does not specify accept-reject criteria andis not intended to be used as a basis for approving compositestructures for service.1.8 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2D3878 Terminology for Composite MaterialsE1316 Terminology for Nondestructive Examinations3.Terminology3.1 DefinitionsTerminology in accordance with Termi-nologies D3878 and E1316 and shall be used where applicable.3.2 Definitions of Terms Specific to This Standard:3.2.1 aspect ratiothe diameter to depth ratio of a flaw.Forirregularly shaped flaws,diameter refers to the minor axis of anequivalent rectangle that approximates the flaw shape and area.3.2.2 discrete discontinuitya thermal discontinuity whoseprojection onto the inspection surface is smaller than the fieldof view of the inspection apparatus.3.2.3 extended discontinuitya thermal discontinuitywhose projection onto the inspection surface completely fillsthe field of view of the inspection apparatus.1This practice is under the jurisdiction of ASTM Committee E07 on Nonde-structive Testing and is the direct responsibility of Subcommittee E07.10 onSpecialized NDT Methods.Current edition approved Oct.1,2014.Published November 2014.Originallyapproved in 2007.Last previous edition approved in 2007 as E2582-07.DOI:10.1520/E2582-07R14.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 3.2.4 first logarithmic derivativethe rate of change of thenatural logarithm of temperature(with preflash temperaturesubtracted)with respect to the natural logarithm of time.3.2.5 inspection surfacethe surface of the specimen that isexposed to the FT apparatus.3.2.6 logarithmic temperature-time plota plot of the natu-ral logarithm of the surface temperature with preflash tempera-ture