ASTM E2582-21

Standard Practice for Infrared Flash Thermography of Composite Panels and Repair Patches Used in Aerospace Applications

SIGNIFICANCE AND USE
5.1 Typically, FT is used to identify flaws that occur in the manufacture of composite structures, or to identify and track flaws that develop during the service lifetime of the structure. Flaws detected with FT include delamination, disbonds, voids, inclusions, foreign object debris, porosity, or the presence of fluid that is in contact with the backside of the inspection surface. For example, the effect of variable ply number (or thickness), bridging, and an insert simulating delamination on heat flow into a composite is shown in Fig. 1 (left). Bridging (Fig. 1, right) or delaminated areas show up as hot spots due to discontinuous heat flow, causing heating to be localized close to the inspection surface. With dedicated signal processing and the use of representative test samples, characterization of flaw depth and size, or measurement of component thickness and thermal diffusivity, may be performed.
FIG. 1 Variation of Heat Flow Into a Composite With Variable Ply Thickness (Scenarios 1, 3, and 4), Bridging (Scenario 2) And an Insert (Scenario 5) (Left), And a Post Layup Line Scan Showing Bright Spots Attributed to Bridging (Right) (Courtesy of NASA Langley Research Center)  
5.2 Since FT is based on the diffusion of thermal energy from the inspection surface of the specimen to the opposing surface (or the depth plane of interest), the practice requires that data acquisition allows sufficient time for this process to occur, and that at the completion of the acquisition process, the radiated surface temperature signal collected by the IR camera is strong enough to be distinguished from spurious IR contributions from background sources or system noise.  
5.3 This method is based on accurate detection of changes in the emitted IR energy emanating from the inspection surface during the cooling process. As the emissivity of the inspection surface falls below that of an ideal blackbody (blackbody emissivity = 1), the signal detected by the IR camera may include comp...
SCOPE
1.1 This practice describes a procedure for detecting subsurface flaws in composite panels and repair patches using Flash Thermography (FT), in which an infrared (IR) camera is used to detect anomalous cooling behavior of a sample surface after it has been heated with a spatially uniform light pulse from a flash lamp array.  
1.2 This practice describes established FT test methods that are currently used by industry, and have demonstrated utility in quality assurance of composite structures during post-manufacturing and in-service examinations.  
1.3 This practice has utility for testing of polymer composite panels and repair patches containing, but not limited to, bismaleimide, epoxy, phenolic, poly(amide imide), polybenzimidazole, polyester (thermosetting and thermoplastic), poly(ether ether ketone), poly(ether imide), polyimide (thermosetting and thermoplastic), poly(phenylene sulfide), or polysulfone matrices; and alumina, aramid, boron, carbon, glass, quartz, or silicon carbide fibers. Typical as-fabricated geometries include uniaxial, cross ply, and angle ply laminates; as well as honeycomb core sandwich core materials.  
1.4 This practice has utility for testing of ceramic matrix composite panels containing, but not limited to, silicon carbide, silicon nitride, and carbon matrix and fibers.  
1.5 This practice applies to polymer or ceramic matrix composite structures with inspection surfaces that are sufficiently optically opaque to absorb incident light, and that have sufficient emissivity to allow monitoring of the surface temperature with an IR camera. Excessively thick samples, or samples with low thermal diffusivities, require long acquisition periods and yield weak signals approaching background and noise levels, and may be impractical for this technique.  
1.6 This practice applies to detection of flaws in a composite panel or repair patch, or at the bonded interface between the panel and a supporting ...

General Information

• Status: Published
• Publication Date: 31-Jan-2021
• ICS: 49.035 - Components for aerospace construction
• Technical Committee: E07 - Nondestructive Testing
• Drafting Committee: E07.10 - Specialized NDT Methods

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: E2582 − 21
Standard Practice for
Infrared Flash Thermography of Composite Panels and
1
Repair Patches Used in Aerospace Applications
This standard is issued under the fixed designation E2582; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript 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. Scope 1.6 Thispracticeappliestodetectionofflawsinacomposite
panel or repair patch, or at the bonded interface between the
1.1 This practice describes a procedure for detecting sub-
panel and a supporting sandwich core or solid substrate. It does
surface flaws in composite panels and repair patches using
not apply to discontinuities in the sandwich core, or at the
Flash Thermography (FT), in which an infrared (IR) camera is
interface between the sandwich core and a second panel on the
used to detect anomalous cooling behavior of a sample surface
far side of the core (with respect to the inspection apparatus).
after it has been heated with a spatially uniform light pulse
1.7 This practice does not specify accept-reject criteria and
from a flash lamp array.
is not intended to be used as a basis for approving composite
1.2 This practice describes established FT test methods that
structures for service.
are currently used by industry, and have demonstrated utility in
1.8 This standard does not purport to address all of the
quality assurance of composite structures during post-
safety concerns, if any, associated with its use. It is the
manufacturing and in-service examinations.
responsibility of the user of this standard to establish appro-
1.3 This practice has utility for testing of polymer compos-
priate safety, health, and environmental practices and deter-
ite panels and repair patches containing, but not limited to,
mine the applicability of regulatory limitations prior to use.
bismaleimide, epoxy, phenolic, poly(amide imide),
1.9 This international standard was developed in accor-
polybenzimidazole, polyester (thermosetting and
dance with internationally recognized principles on standard-
thermoplastic), poly(ether ether ketone), poly(ether imide),
ization established in the Decision on Principles for the
polyimide (thermosetting and thermoplastic), poly(phenylene
Development of International Standards, Guides and Recom-
sulfide), or polysulfone matrices; and alumina, aramid, boron,
mendations issued by the World Trade Organization Technical
carbon, glass, quartz, or silicon carbide fibers. Typical as-
Barriers to Trade (TBT) Committee.
fabricated geometries include uniaxial, cross ply, and angle ply
laminates; as well as honeycomb core sandwich core materials.
2. Referenced Documents
2
1.4 This practice has utility for testing of ceramic matrix
2.1 ASTM Standards:
compositepanelscontaining,butnotlimitedto,siliconcarbide,
D3878 Terminology for Composite Materials
silicon nitride, and carbon matrix and fibers.
E1316 Terminology for Nondestructive Examinations
1.5 This practice applies to polymer or ceramic matrix
3. Terminology
composite structures with inspection surfaces that are suffi-
ciently optically opaque to absorb incident light, and that have
3.1 Definitions—Terminology in accordance with Termi-
sufficient emissivity to allow monitoring of the surface tem-
nologies D3878 and E1316 and shall be used where applicable.
perature with an IR camera. Excessively thick samples, or
3.2 Definitions of Terms Specific to This Standard:
samples with low thermal diffusivities, require long acquisition
3.2.1 aspect ratio, n—the diameter to depth ratio of a flaw;
periods and yield weak signals approaching background and
for irregularly shaped flaws, diameter refers to the minor axis
noise levels, and may be impractical for this technique.
ofanequivalentrectanglethatapproximatestheflawshapeand
area.
1
This practice is under the jurisdiction of ASTM Committee E07 on Nonde-
structive Testing and is the direct responsibility of Subcommittee E07.10 on
2
Specialized NDT Methods. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Feb. 1, 2021. Published March 2021. Originally contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
approved in 2007. Last previous edition approved in 2019 as E2582 – 19. DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/E2582-21. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor D
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: E2582 − 19 E2582 − 21
Standard Practice for
Infrared Flash Thermography of Composite Panels and
1
Repair Patches Used in Aerospace Applications
This standard is issued under the fixed designation E2582; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript 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. Scope
1.1 This practice describes a procedure for detecting subsurface flaws in composite panels and repair patches using Flash
Thermography (FT), in which an infrared (IR) camera is used to detect anomalous cooling behavior of a sample surface after it
has been heated with a spatially uniform light pulse from a flash lamp array.
1.2 This practice describes established FT test methods that are currently used by industry, and have demonstrated utility in quality
assurance of composite structures during post-manufacturing and in-service examinations.
1.3 This practice has utility for testing of polymer composite panels and repair patches containing, but not limited to,
bismaleimide, epoxy, phenolic, poly(amide imide), polybenzimidazole, polyester (thermosetting and thermoplastic), poly(ether
ether ketone), poly(ether imide), polyimide (thermosetting and thermoplastic), poly(phenylene sulfide), or polysulfone matrices;
and alumina, aramid, boron, carbon, glass, quartz, or silicon carbide fibers. Typical as-fabricated geometries include uniaxial, cross
ply, and angle ply laminates; as well as honeycomb core sandwich core materials.
1.4 This practice has utility for testing of ceramic matrix composite panels containing, but not limited to, silicon carbide, silicon
nitride, and carbon matrix and fibers.
1.5 This practice applies to polymer or ceramic matrix composite structures with inspection surfaces that are sufficiently optically
opaque to absorb incident light, and that have sufficient emissivity to allow monitoring of the surface temperature with an IR
camera. Excessively thick samples, or samples with low thermal diffusivities, require long acquisition periods and yield weak
signals approaching background and noise levels, and may be impractical for this technique.
1.6 This practice applies to detection of flaws in a composite panel or repair patch, or at the bonded interface between the panel
and a supporting sandwich core or solid substrate. It does not apply to discontinuities in the sandwich core, or at the interface
between the sandwich core and a second panel on the far side of the core (with respect to the inspection apparatus).
1.7 This practice does not specify accept-reject criteria and is not intended to be used as a basis for approving composite structures
for service.
1
This practice is under the jurisdiction of ASTM Committee E07 on Nondestructive Testing and is the direct responsibility of Subcommittee E07.10 on Specialized NDT
Methods.
Current edition approved July 1, 2019Feb. 1, 2021. Published August 2019March 2021. Originally approved in 2007. Last previous edition approved in 20142019 as
E2582E2582 – 19.- 07(2014). DOI: 10.1520/E2582-19.10.1520/E2582-21.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

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E2582 − 21
1.8 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of
regulatory limitations prior to use.
1.9 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2
2.1 ASTM Standards:
D3878 Terminology for Composite Materials
E1316 Terminology for Nondestructive Examinations
3. Terminology
3.1 Definitions—Terminology in accordance with Terminologies D3878 and E1316 and shall be used where applicable.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 aspect ratio, n—the diameter to depth ratio of a flaw; for irregularly shaped flaws, diameter refers
...