ASTM E569/E569M-20

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Designation: E569/E569M − 13 E569/E569M − 20
Standard Practice for
Acoustic Emission Monitoring of Structures During
Controlled Stimulation
This standard is issued under the fixed designation E569/E569M; 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.
1. Scope*
1.1 This practice provides guidelines for acoustic emission (AE) monitoring of structures, such as pressure vessels, piping
systems, or other structures that can be stressed by mechanical or thermal means.
1.2 The basic functions of an AE monitoring system are to detect, locate, and classify emission sources. Other methods of
nondestructive testing (NDT) may be used to further evaluate the significance of reported acoustic emission sources.
1.3 Units—The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated
in each system mayare not benecessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall
be used independently of the other. Combiningother, and values from the two systems may result in non-conformance with the
standards.shall not be combined.
1.4 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 safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use.
1.5 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
2.1 ASTM Standards:
E543 Specification for Agencies Performing Nondestructive Testing
E650 Guide for Mounting Piezoelectric Acoustic Emission Sensors
E750E976 Practice for Characterizing Acoustic Emission InstrumentationGuide for Determining the Reproducibility of Acoustic
Emission Sensor Response
E1316 Terminology for Nondestructive Examinations
E2374 Guide for Acoustic Emission System Performance Verification
2.2 Other Documents:
SNT-TC-1A Recommended Practice for Nondestructive Testing Personnel Qualification and Certification
ANSI/ASNT CP-189 Standard for Qualification and Certification of Nondestructive Testing Personnel
2.3 AIA Standard:
NAS-410 Certification and Qualification of Nondestructive Testing Personnel
3. Terminology
3.1 Definitions—Definitions of terms relating to acoustic emission may be found in Section B of Terminology E1316.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 AE activity—the presence of acoustic emission during an examination.
This practice is under the jurisdiction of ASTM Committee E07 on Nondestructive Testing and is the direct responsibility of Subcommittee E07.04 on Acoustic Emission
Method.
Current edition approved Jan. 1, 2013Jan. 15, 2020. Published January 2013February 2020. Originally approved in 1976. Last previous edition approved in 20072013 as
E569 - 07.E569/E569M – 13. DOI: 10.1520/E0569_E0569M-13.10.1520/E0569_E0569M-20.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Available from American Society for Nondestructive Testing (ASNT), P.O. Box 28518, 1711 Arlingate Ln., Columbus, OH 43228-0518, http://www.asnt.org.
Available from Aerospace Industries Association of America, Inc. (AIA), 1000 Wilson Blvd., Suite 1700, Arlington, VA 22209-3928, http://www.aia-aerospace.org.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E569/E569M − 20
3.2.1 active source—source, n—one which exhibits increasing cumulative AE activity with increasing or constant stimulus.
3.2.2 AE activity, n—the presence of acoustic emission during an examination.
3.2.3 AE source intensity, n—average energy, counts, or amplitude per hit.
3.2.4 critically active source—source, n—one which exhibits an increasing rate of change of cumulative AE activity with
increasing or constant stimulus.
3.2.5 AE source intensity—critically intense source, n—average energy, counts or amplitude per hit.one in which the AE source
intensity consistently increases with increasing stimulus or with time under constant stimulus.
3.2.6 intense source—source, n—one in which the AE source intensity of an active source consistently exceeds, by a specified
amount, the average AE source intensity of active sources.
3.2.6 critically intense source—one in which the AE source intensity consistently increases with increasing stimulus or with
time under constant stimulus.
4. Summary of Practice
4.1 Acoustic emission examination of a structure usually requires application of a mechanical or thermal stimulus. Such
stimulation produces changes in the stresses in the structure. During stimulation of a structure, AE from discontinuities (such as
cracks and inclusions) and from other areas of stress concentration, or from other acoustic sources (such as leaks, loose parts, and
structural motion) can be detected by an instrumentation system, using sensors which, when stimulated by stress waves, generate
electrical signals.
4.2 In addition to immediate evaluation of the emissions detected during the application of the stimulus, a permanent record of
the number and location of emitting sources and the relative amount of AE detected from each source provides a basis for
comparison with sources detected during the examination and during subsequent stimulation.
5. Significance and Use
5.1 Controlled stimulation i.e. stimulation, that is, the application of mechanical or thermal load, can generate AE from flawed
areas of the structure. Sources may include flaw growth, oxide fracture, crack face stiction and release on load application, and
crack face rubbing.
5.2 The load range above normal service (peak) load is used to propagate fatigue cracks in the plastically strained region ahead
of the crack tip. Crack propagation may not be a reliable source of AE, depending on the alloy and microstructure, the amount (rate)
of crack extension, and possibility of brittle fracture in a segment of crack extension.
5.3 Load increases resulting in significant ductile tearing may produce less emission than expected for the amount of crack
growth. Processes that result in more brittle cleavage fractures are more detectable and produce more emission for smaller amounts
of flaw growth. These include corrosion fatigue and stress corrosion cracking modes of flaw growth, and would also be more likely
in cast or welded structures than in fabricated (forged, rolled, or extruded) structures. Distributed defect structures such as
hydrogen embrittlement, or creep cavitation in high temperature steels, may also produce significant emission without evidence
of an existing crack-like flaw.
5.4 Application and relaxation of load can produce secondary mechanically-induced emission that is not related to flaw
extension. This includes crack face stiction release on loading—usually evidenced by emission at the same rising load value
regardless of peak load; or crack face rubbing on load release as the fracture surfaces come back together.
5.5 The load rate can be a significant concern as instrumentation can become saturated with AE activity. The ability to
differentiate real data from background noise can be compromised.
5.6 Background noise must be fully investigated and minimized before any AE monitoring can begin.
6. Basis of Application
6.1 The following items are subject to contractual agreement between the parties using or referencing this practice.
6.2 Personnel Qualification
6.2.1 If specified in the contractual agreement, personnel performing examinations to this standard shall be qualified in
accordance with a nationally and internationally recognized NDT personnel qualification practice or standard such as
ANSI/ASNT CP-189, SNT-TC-1A, NAS-410, or a similar document and certified by the employer or certifying agency, as
applicable. The practice or standard used and its applicable revision shall be identified in the contractual agreement between the
using parties.
6.3 Qualification of Nondestructive Testing Agencies—If specified in the contractual agreement, NDT agencies shall be qualified
and evaluated as described in PracticeSpecification E543. The applicable edition of PracticeSpecification E543 shall be specified
in the contractual agreement.
E569/E569M − 20
6.4 Timing of Examination—The timing of the examination shall be in accordance with a contractual agreement or with an
established internal procedure.
6.5 Extent of Examination—Many applications will require an arrangement of sensors such that all areas of the structure are
monitored. In other applications, only a portion of the structure may require monitoring.
6.6 Reporting Criteria/Acceptance—Reporting criteria for the examination results shall be in accordance with Sections 11, 12,
and 13.
6.7 Reexamination of Repaired/Reworked Items—Reexamination of repaired/reworked items is not addressed in this standard
and if required shall be specified in a contractual agreement.
7. Examination Preparation
7.1 Before the examination begins, make the following preparations for AE monitoring:
7.1.1 Determine the type, number, and placement of sensors. This requires knowledge of both material and physical
characteristics of the structure and the features of the instrumentation. This determination is also dependent upon the required
precision and accuracy of the examination.
7.1.2 Establish communications between the control point for the application of the stimulus and the AE examination control
center.
7.1.3 Provide a means for continuously recording a measure of the stimulus.
7.1.4 Identify potential sources of extraneous acoustic noise, such as vibration, friction, and fluid flow. Such sources may require
acoustic isolation or control, in order not to mask valid acoustic emissions.
7.1.5 Attach the sensors; both the couplant and sensing device must be compatible with the surface conditions and the
composition of the structural material being examined (see Guide E650).
7.1.6 Verify the AE monitoring system in accordance with Section 9 and Guide E2374.
8. Safety Precautions
8.1 When examining vessels, ambient temperature should not be below the ductile-brittle transition temperature of the pressure
vessel construction material.
9. Calibration and Verification
9.1 Annual calibration and verification of pressure transducer, AE sensors, preamplifiers (if applicable), signal processor
(particularly the signal processor time refe
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