ASTM E1932-12(2022)
(Guide)Standard Guide for Acoustic Emission Examination of Small Parts
Standard Guide for Acoustic Emission Examination of Small Parts
SIGNIFICANCE AND USE
4.1 The purpose of the AE examination is to analyze how an examination object is withstanding the applied load, or if it is suffering from some latent damage. Consequently the emission activity must be evaluated in relation to the applied load.
4.2 The applied load (on the examination object) may include mechanical forces (tension, compression or torsional), internal pressure and thermal gradients. It may be short to long, random or cyclic. The applied load may be controlled by the examiner or may already exist as part of the process. In either case the applied load is measured along with the AE activity.
4.3 Possible applications include the determination of part integrity, quality control assessment of production processes on a sampled or 100 % inspection basis, in-process examination during a period of applied load of a fabrication process (for example, spot welding, bonding, soldering, pressing, etc.), proof-testing after fabrication, monitoring a “region of interest” (or concern) of a structure (for example, bridge joint or repair, vessel, pipe), and re–examination after intervals of service.
SCOPE
1.1 This guide covers techniques for conducting acoustic emission (AE) examinations of small parts. It is confined to examination objects (or defined regions of larger objects) where there is low AE signal attenuation throughout the examination region. This eliminates the consideration of complex attenuation factor corrections and multiple sensor and array placements based on overcoming signal losses over distances.
1.2 The guide assumes a typical AE examination as one where there is a controlled or measured stress acting upon the part being monitored by AE. Particular emphasis is placed on sensor and system selection, sensor placements, stressing considerations, noise reduction/rejection techniques, spatial filtering, location determination, use of guard sensors, collection of AE data, AE data analysis and report. The purpose of the AE examination is to analyze how an object under evaluation is withstanding the applied load.
1.3 Possible applications of this guide includes materials characterization, quality control of production processes, proof testing after fabrication, evaluating regions of interest of larger structures and retesting after intervals of service. The applied load may include mechanical forces (tension, compression or torsional) internal pressure and thermal gradients.
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, health, and environmental 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.
General Information
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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: E1932 − 12 (Reapproved 2022)
Standard Guide for
Acoustic Emission Examination of Small Parts
This standard is issued under the fixed designation E1932; 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 2. Referenced Documents
2.1 ASTM Standards:
1.1 This guide covers techniques for conducting acoustic
E650 Guide for Mounting Piezoelectric Acoustic Emission
emission (AE) examinations of small parts. It is confined to
Sensors
examination objects (or defined regions of larger objects)
E750 Practice for Characterizing Acoustic Emission Instru-
where there is low AE signal attenuation throughout the
mentation
examination region. This eliminates the consideration of com-
E976 GuideforDeterminingtheReproducibilityofAcoustic
plex attenuation factor corrections and multiple sensor and
Emission Sensor Response
array placements based on overcoming signal losses over
E1316 Terminology for Nondestructive Examinations
distances.
E2374 Guide for Acoustic Emission System Performance
1.2 The guide assumes a typical AE examination as one
Verification
where there is a controlled or measured stress acting upon the
part being monitored by AE. Particular emphasis is placed on
3. Terminology
sensor and system selection, sensor placements, stressing
3.1 Definitions:
considerations, noise reduction/rejection techniques, spatial
3.1.1 Terminology related to acoustic emission is defined in
filtering, location determination, use of guard sensors, collec-
Terminology E1316.
tion of AE data, AE data analysis and report. The purpose of
3.2 Definitions of Terms Specific to This Standard:
the AE examination is to analyze how an object under
3.2.1 applied load—a controlled or known force or stress
evaluation is withstanding the applied load.
whichisappliedtoanobjectunderexaminationforthepurpose
1.3 Possible applications of this guide includes materials
ofanalyzingtheobject’sreaction(bymeansofAEmonitoring)
characterization, quality control of production processes, proof
to that stress.
testing after fabrication, evaluating regions of interest of larger
3.2.2 guard sensors—sensors whose primary function is the
structures and retesting after intervals of service. The applied
elimination of extraneous noise based on arrival sequences.
load may include mechanical forces (tension, compression or
3.2.3 spatial discrimination—the process of using one or
torsional) internal pressure and thermal gradients.
more (guard and data) sensors to eliminate extraneous noise
1.4 This standard does not purport to address all of the
based on arrival sequences.
safety concerns, if any, associated with its use. It is the
3.2.4 spatial filtering—ability of an AE system or analysis
responsibility of the user of this standard to establish appro-
to disregard AE activity based on source location of the AE
priate safety, health, and environmental practices and deter-
event.
mine the applicability of regulatory limitations prior to use.
1.5 This international standard was developed in accor-
4. Significance and Use
dance with internationally recognized principles on standard-
4.1 The purpose of theAE examination is to analyze how an
ization established in the Decision on Principles for the
examination object is withstanding the applied load, or if it is
Development of International Standards, Guides and Recom-
suffering from some latent damage. Consequently the emission
mendations issued by the World Trade Organization Technical
activity must be evaluated in relation to the applied load.
Barriers to Trade (TBT) Committee.
4.2 The applied load (on the examination object) may
include mechanical forces (tension, compression or torsional),
This guide is under the jurisdiction of ASTM Committee E07 on Nondestruc-
tive Testing and is the direct responsibility of Subcommittee E07.04 on Acoustic
Emission Method. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Dec. 1, 2022. Published December 2022. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 1998. Last previous edition approved in 2017 as E1932 – 12(2017). Standards volume information, refer to the standard’s Document Summary page on
DOI: 10.1520/E1932-12R22. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E1932 − 12 (2022)
internalpressureandthermalgradients.Itmaybeshorttolong, result. In cases where the applied load is part of the process
random or cyclic. The applied load may be controlled by the being monitored, a suitable time forAE monitoring needs to be
examiner or may already exist as part of the process. In either
determined where process noise is low and applied load (for
case the applied load is measured along with the AE activity. AE examination purposes) maximum. Sometimes (if needed)
the applied loading can be altered to achieve this without
4.3 Possible applications include the determination of part
compromising the process (for example, inserting a short load
integrity,qualitycontrolassessmentofproductionprocesseson
hold at maximum load).
a sampled or 100 % inspection basis, in-process examination
(1) In cases where the applied load is controlled with the
during a period of applied load of a fabrication process (for
example, spot welding, bonding, soldering, pressing, etc.), examination, then consideration should be given to design the
loading schedule to appropriately stress the examination object
proof-testing after fabrication, monitoring a “region of inter-
est” (or concern) of a structure (for example, bridge joint or in order to excite “latent flaws” without over-stressing or
repair, vessel, pipe), and re–examination after intervals of damaging the object. In addition, the loading schedule should
service. be designed to provide best insight into the integrity of the part
(for example, implementing a load schedule to evaluate the
5. Procedure
“Kaiser effect”).
5.1 Preliminary Information:
5.1.2.3 Sensor Types—Considerations that should guide the
5.1.1 Before examination, the following information, where
user into proper selection include the sensor’s frequency range,
relevant, should be obtained by the AE examiner:
size (including sensor height, diameter and weight), maximum
5.1.1.1 Type of object to be examined, together with layout
or minimum temperature specification, the sensor’s sensitivity
drawings or sketches.
and frequency response, and acoustic impedance matching of
5.1.1.2 Material specifications (including details of heat
the sensor and part.
treatment where possible).
5.1.2.4 Location of Sensors and Placement Strategy—
5.1.1.3 Proposed or existing applied load specification to-
Considerations need to be given to the number of sensors
gether with a layout or sketch of the pressure/stress application
required for the examination, their placement strategy and
system.
location on the part to be monitored.
5.1.1.4 Information regarding the measuring or recording of
(1) In cases where background noise can be controlled or
theappliedloadmustalsobeobtainedinordertodeterminethe
does not exist, then a single sensor near the expected source of
compatibility with the AE equipment.
the AE is sufficient.
5.1.1.5 Potential sources of background noise and the iso-
(2) In cases where there are a limited number of back-
lating mechanisms applied thereto.
ground noise sources (such as the grips in a tension test), a
5.1.1.6 Previous history, including the maximum applied
single AE data sensor near the expected source of AE and the
load to which the object or system has been subjected.
use of a guard sensor near each background source will
5.1.1.7 Where possible, locations of known discontinuities
effectively block noises that emanate from a region closer to
and the general results of earlier AE or other NDE examina-
the guard sensors than to the AE data sensor. Alternatively, a
tions.
group of two or more sensors can be strategically placed to
5.1.1.8 Results of earlier examinations on similar objects.
perform spatial discrimination of background noise and allow
5.1.2 Before examination, theAE examiner should consider
processing of AE events.
the following information. Some details need to be coordinated
(3) In cases where extraneous noise cannot be controlled
with the on-site management or responsible personnel:
and could be emanating from any or all directions, a multiple-
5.1.2.1 The Type of AE Equipment to be Used—
sensor location strategy (such as linear or planar location)
Considerations should include the number of channels, the
should be considered. In this situation, enough sensors should
frequency range of the instrument’s filters, the real-time data
be specified to allow for an accurate source location, and
processing rates for the type of application, its location/guard/
means should be available to allow for the application of
spatial filtering capabilities, the type of data being collected
spatial filtering and/or spatial discrimination so that only data
(for example, RMS, ASL, AE feature based or waveform
emanating from the region of interest is processed as relevant
based) and the compatibility of the system to monitor and
AE data.
record the applied load during the AE examination. These
5.1.2.5 Data to be Recorded—The AE examiner should
items must be able to perform at the anticipated levels of
know in advance the data and information to be recorded and
performance expected during the examination. In addition,
have all the necessary equipment, hardware, accessories and
consideration should be given to the data analysis, display and
software to acquire, store, and process this information. Other
replay capabilities of the equipment to assure its ability to
process the stored data in a way needed to arrive at a than the equipment forAE monitoring, appropriate sensors and
devices are required for measuring and recording the applied
satisfactory conclusion and examination result.
5.1.2.2 Application of Load—Consideration should be given load and other load or condition related parametric data.
to the application of the load in relation to the integrity of the Details of any in
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