ASTM F2174-02
(Practice)Standard Practice for Verifying Acoustic Emission Sensor Response
Standard Practice for Verifying Acoustic Emission Sensor Response
SIGNIFICANCE AND USE
Degradation in sensor performance can occur due to dropping, mechanical shock while mounted on the test structure, temperature cycles, and so forth. It is necessary and desirable to have a simple measurement procedure that will check the consistency of sensor response, while holding all other variables constant.
While test blocks of many different kinds have been used for this purpose for many years, an acrylic polymer rod offers the best all-around combination of suitable acoustic properties, practical convenience, ease of procurement, and low cost.
Because the acoustic properties of the acrylic rod are known to depend on temperature, this practice requires that the rod, sensors, and couplant be stabilized at the same working temperature, prior to application of the practice.
Attention should be paid to storage conditions for the acrylic polymer rod. For example, it should not be left in a freezing or hot environment overnight, unless it is given time for temperature stabilization before use.
Properly applied and with proper record keeping, this practice can be used in many ways, such as:
3.5.1 To determine when a sensor is no longer suitable for use.
3.5.2 To check sensors that have been exposed to high-risk conditions such as dropping, overheating, and so forth.
3.5.3 To get an early warning of sensor degradation over time.
3.5.4 To obtain matched sets of sensors and preamplifiers.
3.5.5 To verify sensors quickly but accurately in the field, and to assist troubleshooting when a channel does not pass a performance check.
SCOPE
1.1 This practice is used for routinely checking the sensitivity of acoustic emission (AE) sensors. It is intended to provide a reliable, precisely specified way of comparing a set of sensors or telling whether an individual sensor's sensitivity has degraded during its service life, or both.
1.2 The procedure in this practice is not a "calibration" and does not give frequency-response information.
1.3 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
1.4 This practice does not purport to recommend one sensor manufacturer over another nor does it imply that one type of sensor will react differently from another when using this procedure.
1.5 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.
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Standards Content (Sample)
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An American National Standard
Designation: F 2174 – 02
Standard Practice for
Verifying Acoustic Emission Sensor Response
This standard is issued under the fixed designation F 2174; 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.
1. Scope offers the best all-around combination of suitable acoustic
properties, practical convenience, ease of procurement, and
1.1 This practice is used for routinely checking the sensi-
low cost.
tivity of acoustic emission (AE) sensors. It is intended to
3.3 Because the acoustic properties of the acrylic rod are
provide a reliable, precisely specified way of comparing a set
known to depend on temperature, this practice requires that the
of sensors or telling whether an individual sensor’s sensitivity
rod, sensors, and couplant be stabilized at the same working
has degraded during its service life, or both.
temperature, prior to application of the practice.
1.2 The procedure in this practice is not a “calibration” and
3.4 Attention should be paid to storage conditions for the
does not give frequency-response information.
acrylic polymer rod. For example, it should not be left in a
1.3 The values stated in SI units are to be regarded as the
freezing or hot environment overnight, unless it is given time
standard. The values given in parentheses are for information
for temperature stabilization before use.
only.
3.5 Properly applied and with proper record keeping, this
1.4 This practice does not purport to recommend one sensor
practice can be used in many ways, such as:
manufacturer over another nor does it imply that one type of
3.5.1 To determine when a sensor is no longer suitable for
sensor will react differently from another when using this
use.
procedure.
3.5.2 To check sensors that have been exposed to high-risk
1.5 This standard does not purport to address all of the
conditions such as dropping, overheating, and so forth.
safety concerns, if any, associated with its use. It is the
3.5.3 To get an early warning of sensor degradation over
responsibility of the user of this standard to establish appro-
time.
priate safety and health practices and determine the applica-
3.5.4 To obtain matched sets of sensors and preamplifiers.
bility of regulatory limitations prior to use.
3.5.5 To verify sensors quickly but accurately in the field,
2. Referenced Documents and to assist troubleshooting when a channel does not pass a
performance check.
2.1 ASTM Standards:
E 650 Guide for Mounting PiezoelectricAcoustic Emission
4. Apparatus
Sensors
4.1 Acrylic Polymer Cylindrical Rod (Fig. 1) should be
E 750 Practice for CharacterizingAcoustic Emission Instru-
used. The actual material of the acrylic polymer rod is
mentation
poly(methylmethacrylate)(PMMA).
E 976 Guide for Determining the Reproducibility ofAcous-
4.1.1 Dimensions of the rod should be 78.74 cm (31 in.)
tic Emission Sensor Response
long by 3.81 cm (1.5 in.) in diameter with ends cut true and
3. Significance and Use
smooth with a surface finish of 0.4 µm rms (0.16 µin.).
4.1.2 Other lengths of rod are acceptable, provided that
3.1 Degradation in sensor performance can occur due to
there is sufficient distance to attenuate and prevent reflected
dropping, mechanical shock while mounted on the test struc-
signals from the non-sensor end of the rod reaching the sensor.
ture, temperature cycles, and so forth. It is necessary and
4.1.3 A permanent reference mark (for example, an “X”) is
desirable to have a simple measurement procedure that will
placed on the rod at a distance of 10.16 cm (4 in.) from one
check the consistency of sensor response, while holding all
end; this marks the spot where the lead is to be broken. It is
other variables constant.
convenient to provide a very small spotface, for example, 0.79
3.2 While test blocks of many different kinds have been
6 0.05-mm (0.031 6 0.002-in.) diameter and 0.076 to 0.178
used for this purpose for many years, an acrylic polymer rod
mm (0.003 to 0.007 in.) deep at this reference mark point, to
rest the tip of the pencil lead to avoid slippage during the lead
This practice is under the jurisdiction of ASTM Committee F18 on Electrical
break process.
Protective Equipment for Workers and is the direct responsibility of Subcommittee
F18.55 on Acoustic Emission.
Current edition approved March 10, 2002. Published May 2002.
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.
F2174–02
FIG. 1 Acrylic Rod Description
4.2 Hsu-Nielsen Pencil Lead Break Source, 0.3 or 0.5 mm. the lead flies off to one side and does not hit the sensor. Fingers
A Nielsen shoe as described in Guide E 976 is optional. may be rested on the rod on the side away from the sensor to
4.3 Sensor(s), to be tested. steady the pencil, but there must be no finger conta
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