JJF 1505-2015 Calibration specification for acoustic emission instrumentation
1 Scope
This specification is applicable to the calibration of the main unit of acoustic emission instrumentation, excluding the sensor and preamplifier.
2 Normative references
The following documents are referenced in this specification:
JJF 1001 General terms in metrology and their definitions
JJF 1034 Metrological terms and their definitions for acoustics
GB 3102.7-1993 Quantities and units - Acoustics
GB/T 12604.4-2005 Non-destructive testing - Terminology - Terms used in acoustic emission testing
JB/T 8283-1999 Methods for testing the operating characteristics of acoustic emission instrumentation
ASTM E0750-10 Practice for characterizing acoustic emission instrumentation
For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
3 Terms and definitions
The quantities and units specified in GB 3102.7-1993 are adopted in this specification.
For the purposes of this specification, the terms and definitions given in JJF 1001 and JJF 1034 and the following apply.
3.1
acoustic emission
phenomenon whereby transient elastic waves are generated by the rapid release of energy within a material
[GB/T 12604.4-2005, Definition 2.1]
3.2
acoustic emission signal amplitude
peak voltage of the maximum amplitude obtained from the waveform of the acoustic emission signal
Note: Unit: V, typically expressed in dB, with a reference value of 1 μV.
3.3
threshold value
preset voltage value above which an acoustic emission signal amplitude can be detected, typically expressed in dB, with a reference value of 1 μV
Note: The threshold value is also commonly referred to as threshold.
3.4
hit
any signal that exceeds the threshold value and causes a channel of the acoustic emission instrumentation to acquire data
3.5
rise time
time interval between the first threshold crossing and the maximum amplitude of an acoustic emission signal
3.6
duration time
time interval between the first threshold crossing of the acoustic emission signal and its final return to the threshold
3.7
ring-down count
number of times the amplitude crosses a preset threshold value within each acoustic emission hit signal
3.8
crosstalk
noise resulting from signal coupling between channels
3.9
self noise
equivalent load noise present when the acoustic emission instrumentation is connected to the sensor and preamplifier
4 General
Acoustic emission instrumentation is used to detect acoustic emission signals and to analyze and determine the characteristics of the acoustic emission source. The corresponding parameters of acoustic emission instrumentation include self noise, frequency range, dynamic range, and acoustic emission waveform parameters (rise time, duration time, peak amplitude, and ring-down count). See Figure 1 for its basic characteristic parameters.
Introduction i
1 Scope
2 Normative references
3 Terms and definitions
3.1 acoustic emission
3.2 acoustic emission signal amplitude
3.3 threshold value
3.4 hit
3.5 rise time
3.6 duration time
3.7 ring-down count
3.8 crosstalk
3.9 self noise
4 General
5 Metrological characteristics
5.1 Self noise
5.2 Frequency range
5.3 Dynamic range
5.4 Inter-channel crosstalk
5.5 Waveform parameters
6 Calibration conditions
6.1 Environmental conditions
6.2 Measurement standard and other equipment
7 Calibration items and methods
7.1 Calibration items
7.2 Calibration methods
8 Expression of calibration results
8.1 Calibration data processing
8.2 Calibration certificate
8.3 Measurement uncertainty of calibration result
9 Recalibration time interval
Annex A Recommended format of the inner pages of the calibration certificate of the acoustic emission instrumentation
Annex B An example to evaluate the uncertainty of calibration results of acoustic emission instrumentation
