ASTM F2174-02(2008)
(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:
To determine when a sensor is no longer suitable for use.
To check sensors that have been exposed to high-risk conditions such as dropping, overheating, and so forth.
To get an early warning of sensor degradation over time.
To obtain matched sets of sensors and preamplifiers.
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.
General Information
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Standards Content (Sample)
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Designation: F2174 − 02(Reapproved 2008)
Standard Practice for
Verifying Acoustic Emission Sensor Response
This standard is issued under the fixed designation F2174; 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 structure, temperature cycles, and so forth. It is necessary and
desirable to have a simple measurement procedure that will
1.1 This practice is used for routinely checking the sensi-
check the consistency of sensor response, while holding all
tivity of acoustic emission (AE) sensors. It is intended to
other variables constant.
provide a reliable, precisely specified way of comparing a set
of sensors or telling whether an individual sensor’s sensitivity 3.2 While test blocks of many different kinds have been
has degraded during its service life, or both. used for this purpose for many years, an acrylic polymer rod
offers the best all-around combination of suitable acoustic
1.2 The procedure in this practice is not a “calibration” and
properties, practical convenience, ease of procurement, and
does not give frequency-response information.
low cost.
1.3 The values stated in SI units are to be regarded as the
3.3 Because the acoustic properties of the acrylic rod are
standard. The values given in parentheses are for information
known to depend on temperature, this practice requires that the
only.
rod, sensors, and couplant be stabilized at the same working
1.4 This practice does not purport to recommend one sensor
temperature, prior to application of the practice.
manufacturer over another nor does it imply that one type of
3.4 Attention should be paid to storage conditions for the
sensor will react differently from another when using this
acrylic polymer rod. For example, it should not be left in a
procedure.
freezing or hot environment overnight, unless it is given time
1.5 This standard does not purport to address all of the
for temperature stabilization before use.
safety concerns, if any, associated with its use. It is the
3.5 Properly applied and with proper record keeping, this
responsibility of the user of this standard to establish appro-
practice can be used in many ways, such as:
priate safety and health practices and determine the applica-
3.5.1 To determine when a sensor is no longer suitable for
bility of regulatory limitations prior to use.
use.
2. Referenced Documents 3.5.2 To check sensors that have been exposed to high-risk
2 conditions such as dropping, overheating, and so forth.
2.1 ASTM Standards:
3.5.3 To get an early warning of sensor degradation over
E650 Guide for Mounting Piezoelectric Acoustic Emission
time.
Sensors
3.5.4 To obtain matched sets of sensors and preamplifiers.
E750 Practice for Characterizing Acoustic Emission Instru-
3.5.5 To verify sensors quickly but accurately in the field,
mentation
and to assist troubleshooting when a channel does not pass a
E976 GuideforDeterminingtheReproducibilityofAcoustic
performance check.
Emission Sensor Response
4. Apparatus
3. Significance and Use
4.1 Acrylic Polymer Cylindrical Rod (Fig. 1) should be
3.1 Degradation in sensor performance can occur due to
used. The actual material of the acrylic polymer rod is
dropping, mechanical shock while mounted on the test
poly(methylmethacrylate)(PMMA).
4.1.1 Dimensions of the rod should be 78.74 cm (31 in.)
This practice is under the jurisdiction of ASTM Committee F18 on Electrical
long by 3.81 cm (1.5 in.) in diameter with ends cut true and
Protective Equipment for Workers and is the direct responsibility of Subcommittee
smooth with a surface finish of 0.4 µm rms (0.16 µin.).
F18.55 on Inspection and Non-Destructive Test Methods for Aerial Devices.
4.1.2 Other lengths of rod are acceptable, provided that
Current edition approved Oct. 1, 2008. Published December 2008. Originally
there is sufficient distance to attenuate and prevent reflected
approved in 2002. Last previous edition approved in 2002 as F2174-02. DOI:
10.1520/F2174-02R08.
signals from the non-sensor end of the rod reaching the sensor.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
4.1.3 A permanent reference mark (for example, an “X”) is
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
placed on the rod at a distance of 10.16 cm (4 in.) from one
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. end; this marks the spot where the lead is to be broken. It is
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F2174 − 02 (2008)
FIG. 1 Acrylic Rod Description
convenient to provide a very small spotface, for example, 0.79 angle between the lead and the surface. Hold the pencil
6 0.05-mm (0.031 6 0.002-in.) diameter and 0.076 to 0.178 pointing toward the sensor but with its axis approximately 22°
mm (0.003 to 0.007 in.) deep at this reference mark point, to (a quarter of a right angle) off from the axis of the rod, so that
rest the tip of the pencil lead to avoid slippage during the lead the lead flies off to one side and does not hit the sensor. Fingers
break process. may
...
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