4 Comparative Analysis of the International Status of Acoustic …
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standards combine the parameters from the American and European standards, and
also proposes other parameters based on the different functions of the standards.
For example, noise, overload recovery time, input impedance and output impedance
are proposed in the instrument performance test standard, temperature resistance is
proposed in the product standard, and crosstalk between channels is proposed in the
calibration standard.
4.4 Comparative Analysis of Performance Test of AE
Sensors
4.4.1 Testing Status and Standards
Each newly produced AE sensor is accompanied by a sensitivity test report with
spectrum curves. After it is put into use, the AE sensor is generally calibrated once
a year. The performance of the sensor will gradually decrease with the increase in
use. The sensor may be damaged when the environment is harsh or the operation is
improper. When the detection sensitivity of the sensor decreases significantly, the
performance test should be carried out in time to verify whether it meets the detection
needs.
The performance test standards for AE sensors mainly include American ASTM
standards, European EN standards, ISO standards and Chinese standards, as shown
in Table 4.3.
The AE sensor test standards appeared later than the instrument test standards.
The United States first developed and issued ASTM E976 in 1984 and the latest
version was revised in 2015. This standard provides simple procedures for testing
or comparing the performance of AE sensors. These procedures allow the user to
check for degradation of a sensor or to select sets of sensors with nearly identical
performances, but not capable of providing an absolute calibration. Then ASTM also
developed and issued the other 4 standards. ASTM E650M proposes the AE sensor
mounting method, requirements and response verification after sensor mounting.
ASTM E2075M proposes to use an acrylic rod to verify the sensitivity of the AE
sensor by breaking the lead. ASTM E1106 and ASTM E1781M are important standards for the calibration of AE sensors. They provide primary and secondary calibration methods for sensors. The first editions of the two standards were issued in 1986
and 1996 respectively. The European EN has only one technical report EN ISO/TR
13115 which was jointly developed by CEN and ISO. This report describes the
methods for the calibration of AE transducers by the reciprocity technique. In addition to the above technical report jointly developed with CEN, ISO has also issued
two standards ISO 12713 and ISO 12714. ISO 12713 is similar to ASTM E1106.
It specifies a method for the absolute calibration of AE transducers. The calibration
yields the frequency response of a transducer to waves of the type normally encountered in AE work. This standard is applicable to secondary standard transducers and
45
standards combine the parameters from the American and European standards, and
also proposes other parameters based on the different functions of the standards.
For example, noise, overload recovery time, input impedance and output impedance
are proposed in the instrument performance test standard, temperature resistance is
proposed in the product standard, and crosstalk between channels is proposed in the
calibration standard.
4.4 Comparative Analysis of Performance Test of AE
Sensors
4.4.1 Testing Status and Standards
Each newly produced AE sensor is accompanied by a sensitivity test report with
spectrum curves. After it is put into use, the AE sensor is generally calibrated once
a year. The performance of the sensor will gradually decrease with the increase in
use. The sensor may be damaged when the environment is harsh or the operation is
improper. When the detection sensitivity of the sensor decreases significantly, the
performance test should be carried out in time to verify whether it meets the detection
needs.
The performance test standards for AE sensors mainly include American ASTM
standards, European EN standards, ISO standards and Chinese standards, as shown
in Table 4.3.
The AE sensor test standards appeared later than the instrument test standards.
The United States first developed and issued ASTM E976 in 1984 and the latest
version was revised in 2015. This standard provides simple procedures for testing
or comparing the performance of AE sensors. These procedures allow the user to
check for degradation of a sensor or to select sets of sensors with nearly identical
performances, but not capable of providing an absolute calibration. Then ASTM also
developed and issued the other 4 standards. ASTM E650M proposes the AE sensor
mounting method, requirements and response verification after sensor mounting.
ASTM E2075M proposes to use an acrylic rod to verify the sensitivity of the AE
sensor by breaking the lead. ASTM E1106 and ASTM E1781M are important standards for the calibration of AE sensors. They provide primary and secondary calibration methods for sensors. The first editions of the two standards were issued in 1986
and 1996 respectively. The European EN has only one technical report EN ISO/TR
13115 which was jointly developed by CEN and ISO. This report describes the
methods for the calibration of AE transducers by the reciprocity technique. In addition to the above technical report jointly developed with CEN, ISO has also issued
two standards ISO 12713 and ISO 12714. ISO 12713 is similar to ASTM E1106.
It specifies a method for the absolute calibration of AE transducers. The calibration
yields the frequency response of a transducer to waves of the type normally encountered in AE work. This standard is applicable to secondary standard transducers and