ASTM E1932-97(2002)e1

Standard Guide for Acoustic Emission Examination of Small Parts

SCOPE
1.1 This guide covers techniques for conducting acoustic emission (AE) examinations of small parts. It is confined to test objects (or defined regions of larger objects) where there is low AE signal attenuation throughout the test 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.  
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 and health practices and determine the applicability of regulatory limitations prior to use.

General Information

• Status: Historical
• Publication Date: 09-Dec-1997
• ICS: 17.140.01 - Acoustic measurements and noise abatement in general
• Technical Committee: E07 - Nondestructive Testing
• Drafting Committee: E07.04 - Acoustic Emission Method

Relations

• Replaced By: ASTM E1932-07 - Standard Guide for Acoustic Emission Examination of Small Parts
• Effective Date: 01-Jul-2007
• Referred By: ASTM E2533-21 - Standard Guide for Nondestructive Examination of Polymer Matrix Composites Used in Aerospace Applications
• Effective Date: 10-Dec-1997
• Referred By: ASTM E543-21 - Standard Specification for Agencies Performing Nondestructive Testing
• Effective Date: 10-Dec-1997
• Referred By: ASTM C1624-22 - Standard Test Method for Adhesion Strength and Mechanical Failure Modes of Ceramic Coatings by Quantitative Single Point Scratch Testing
• Effective Date: 10-Dec-1997
• Referred By: ASTM E3100-22 - Standard Guide for Acoustic Emission Examination of Concrete Structures
• Effective Date: 10-Dec-1997

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
e1
Designation: E 1932 – 97 (Reapproved 2002)
Standard Guide for
Acoustic Emission Examination of Small Parts
This standard is issued under the fixed designation E 1932; 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 (e) indicates an editorial change since the last revision or reapproval.
e NOTE—Editorially replaced the term “test” with “examination” wherever appropriate in July 2002. Also, there were
miscellaneous editorial corrections made throughout the standard in July 2002.
1. Scope E 976 Guide for Determining the Reproducibility ofAcous-
tic Emission Sensor Response
1.1 This guide covers techniques for conducting acoustic
E 1316 Terminology For Nondestructive Examinations
emission (AE) examinations of small parts. It is confined to
examination objects (or defined regions of larger objects)
3. Terminology
where there is low AE signal attenuation throughout the
3.1 Definitions:
examination region. This eliminates the consideration of com-
3.1.1 Terminology related to acoustic emission is defined in
plex attenuation factor corrections and multiple sensor and
Terminology E 1316.
array placements based on overcoming signal losses over
3.2 Definitions of Terms Specific to This Standard:
distances.
3.2.1 applied load—a controlled or known force or stress
1.2 The guide assumes a typical AE examination as one
whichisappliedtoanobjectunderexaminationforthepurpose
where there is a controlled or measured stress acting upon the
ofanalyzingtheobject’sreaction(bymeansofAEmonitoring)
part being monitored by AE. Particular emphasis is placed on
to that stress.
sensor and system selection, sensor placements, stressing
3.2.2 guard sensors—sensors whose primary function is the
considerations, noise reduction/rejection techniques, spatial
elimination of extraneous noise based on arrival sequences.
filtering, location determination, use of guard sensors, collec-
3.2.3 spatial discrimination—the process of using one or
tion of AE data, AE data analysis and report. The purpose of
more (guard and data) sensors to eliminate extraneous noise
the AE examination is to analyze how an object under
based on arrival sequences.
evaluation is withstanding the applied load.
3.2.4 spatial filtering—ability of an AE system or analysis
1.3 Possible applications of this guide includes materials
to disregard AE activity based on source location of the AE
characterization, quality control of production processes, proof
event.
testing after fabrication, evaluating regions of interest of larger
structures and retesting after intervals of service. The applied
4. Significance and Use
load may include mechanical forces (tension, compression or
4.1 ThepurposeoftheAEexaminationistoanalyzehowan
torsional) internal pressure and thermal gradients.
examination object is withstanding the applied load, or if it is
1.4 This standard does not purport to address all of the
suffering from some latent damage. Consequently the emission
safety concerns, if any, associated with its use. It is the
activity must be evaluated in relation to the applied load.
responsibility of the user of this standard to establish appro-
4.2 The applied load (on the examination object) may
priate safety and health practices and determine the applica-
include mechanical forces (tension, compression or torsional),
bility of regulatory limitations prior to use.
internalpressureandthermalgradients.Itmaybeshorttolong,
random or cyclic. The applied load may be controlled by the
2. Referenced Documents
examiner or may already exist as part of the process. In either
2.1 ASTM Standards:
case the applied load is measured along with the AE activity.
E 650 Guide for Mounting PiezoelectricAcoustic Emission
4.3 Possible applications are determination of part integrity,
Sensors
quality control assessment of production processes on a
E 750 Practice for CharacterizingAcoustic Emission Instru-
2 sampled or 100 % inspection basis, in-process examination
mentation
during a period of applied load of a fabrication process (for
example, spot welding, bonding, soldering, pressing, etc.),
This guide is under the jurisdiction of ASTM Committee E07 on Nondestruc-
proof-testing after fabrication, monitoring a “region of inter-
tive Testing and is the direct responsibility of Subcommittee E07.04 on Acoustic
est” (or concern) of a structure (for example, bridge joint or
Emission Method.
repair, vessel, pipe), and re–examination after intervals of
Current edition approved December 10, 1997. Published June 1998.
service.
Annual Book of ASTM Standards,Vol 03.03.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
e1
E 1932 – 97 (2002)
5. Procedure size (including sensor height, diameter and weight), maximum
or minimum temperature specification, the sensor’s sensitivity
5.1 Preliminary Information:
and frequency response, and acoustic impedance matching of
5.1.1 Before examination, the following information, where
the sensor and part.
relevant, should be obtained by the AE examiner:
5.1.2.4 Location of Sensors and Placement Strategy—
5.1.1.1 Type of object to be examined, together with layout
Considerations need to be given to the number of sensors
drawings or sketches.
required for the examination, their placement strategy and
5.1.1.2 Material specifications (including details of heat
location on the part to be monitored.
treatment where possible).
5.1.1.3 Proposed or existing applied load specification to- (1) In cases where background noise can be controlled or
does not exist, then a single sensor near the expected source of
gether with a layout or sketch of the pressure/stress application
system. the AE is sufficient.
5.1.1.4 Information regarding the measuring or recording of
(2) In cases where there are a limited number of background
theappliedloadmustalsobeobtainedinordertodeterminethe
noise sources (such as the grips in a tension test), a single AE
compatibility with the AE equipment.
data sensor near the expected source of AE and the use of a
5.1.1.5 Potential sources of background noise and the iso-
guard sensor near each background source will effectively
lating mechanisms applied thereto.
block noises that emanate from a region closer to the guard
5.1.1.6 Previous history, including the maximum applied
sensors than to the AE data sensor. Alternatively, a group of
load to which the object or system has been subjected.
two or more sensors can be strategically placed to perform
5.1.1.7 Where possible, locations of known discontinuities spatial discrimination of background noise and allow process-
and the general results of earlier AE or other NDE.
ing of AE events.
5.1.1.8 Results of earlier examinations on similar objects.
(3) In cases where extraneous noise cannot be controlled and
5.1.2 Before examination, theAE examiner should consider
could be emanating from any or all directions, a multiple-
the following information. Some details need to be coordinated
sensor location strategy (such as linear or planar location)
with the on-site management or responsible personnel:
should be considered. In this situation, enough sensors should
5.1.2.1 The Type of AE Equipment to be Used—
be specified to allow for an accurate source location, and
Considerations should include the number of channels, the
means should be available to allow for the application of
frequency range of the instrument’s filters, the real-time data
spatial filtering and/or spatial discrimination so that only data
processing rates for the type of application, its location/guard/
emanating from the region of interest is processed as relevant
spatial filtering capabilities, the type of data being collected
AE data.
(for example, RMS, ASL, AE feature based or waveform
5.1.2.5 Data to be Recorded—The AE examiner should
based) and the compatibility of the system to monitor and
know in advance the data and information to be recorded and
record the applied load during the AE examination. These
have all the necessary equipment, hardware, accessories and
items must be able to perform at the anticipated levels of
software to acquire, store, and process this information. Other
performance expected during the examination. In addition,
than the equipment forAE monitoring, appropriate sensors and
consideration should be given to the data analysis, display and
devices are required for measuring and recording the applied
replay capabilities of the equipment to assure its ability to
load and other load or condition related parametric data.
process the stored data in a way needed to arrive at a
Details of any interfaces may need to be coordinated with the
satisfactory conclusion and examination result.
examination site management and personnel.
5.1.2.2 Application of Load—Consideration should be
5.1.2.6 Applicability and possible limitations of the method
given to the application of the load in relation to the integrity
for the particular examination.
of the examination object and achieving a successful AE
5.1.2.7 Any preconditions necessary for conducting the AE
examination result. In cases where the applied load is part of
examination such as surface preparation or limitation of
the process being monitored, a suitable time forAE monitoring
pressurization rate needs to be coordinated with the
needs to be determined where process noise is low and applied
examination-site management or responsible personnel.
load (for AE examination purposes) maximum. Sometimes (if
5.2 Sensor Installation—The methods and procedures used
needed) the applied loading can be altered to achieve this
in mounting AE sensors can have significant effects upon the
without compromising the process (for example, inserting a
performance of those sensors. Optimum and reproducible
short load hold at maximum load).
detection of AE requires both appropriate sensor-mounting
(1) In cases where the applied load is controlled with the
fixtures and consistent senso
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