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H. Vallen
The chapter “Introduction” of the initial draft lists some advantages of the
proposed face-to-face (F2F) method, e.g. the avoidance of a heavy transfer block, a
simpler handling, the absence of indirect paths between source and sensor, the good
reproducibility. It also presents the disadvantage of the F2F method: The obtained
sensitivity spectra are only valid for plane waves arriving in normal direction. Cancellation effects, that happen with e.g. Rayleigh waves, depending on the dimension of
the sensitive face of the sensor, do not occur with the F2F method and hence, are not
considered.
3.2 Scope
Reproduced from Chap. 1 of the initial draft: “This document specifies (a) a method
of determining the receiving sensitivity spectrum of a piezoelectric acoustic emission
sensor in absolute units of volt output per units of particle motion input. Units of
motion can be millimeter per second velocity or nanometer displacement, over a
frequency range used for acoustic emission testing, from about 20 kHz to 1 MHz,
whereby the sensor is stimulated by a particle velocity pulse in normal direction to
the sensor’s face from a directly coupled piezoelectric transmitter; and (b) a method
of determining a transmitter’s transmitting sensitivity spectrum in absolute units of
millimeter per second output per unit of volt input, by measuring both, the particle
velocity pulse over the transmitter’s active face and the transmitter’s input voltage
spectrum, by using measurement channels of common frequency characteristics as
offered by a hireable scanning laser vibrometer.
This document does not include the effects on a sensor’s response, when the length
of the wave passing across the sensor’s sensitive face is shorter than about 5 times
of the dimension of the sensor’s sensitive face.”
3.3 Other Chapters
Three mandatory chapters (Chaps. 2–4) concern: Normative references, Terms and
definitions, Symbols and abbreviations.
Chapter 5 describes the face-to-face setup (F2F), which is used to determine the
SUT’s receiving sensitivity, and the laser vibrometer setup (LVM), which is used to
determine the transmitter’s transmitting sensitivity.
Chapter 6 defines all requirements on the hardware described in Chap. 5.
Chapter 7 “Determination of the receiving sensitivity” contains subchapters
“7.1 Scaling of FFT results”, “7.2 Interpolation of time series data of 8–25 ns
sampling interval”, “7.3 DC offset compensation”, “7.4 Recommended stimulation
signal”, “7.5 Windowing of SUT responses”, “7.6 Relevant spectra for sensor sensitivity determination”, “7.7 Formulae for obtaining sensitivities and F2F velocity”,
“7.8 Examples of velocity sensitivity spectra” (of a wideband, a narrowband and
H. Vallen
The chapter “Introduction” of the initial draft lists some advantages of the
proposed face-to-face (F2F) method, e.g. the avoidance of a heavy transfer block, a
simpler handling, the absence of indirect paths between source and sensor, the good
reproducibility. It also presents the disadvantage of the F2F method: The obtained
sensitivity spectra are only valid for plane waves arriving in normal direction. Cancellation effects, that happen with e.g. Rayleigh waves, depending on the dimension of
the sensitive face of the sensor, do not occur with the F2F method and hence, are not
considered.
3.2 Scope
Reproduced from Chap. 1 of the initial draft: “This document specifies (a) a method
of determining the receiving sensitivity spectrum of a piezoelectric acoustic emission
sensor in absolute units of volt output per units of particle motion input. Units of
motion can be millimeter per second velocity or nanometer displacement, over a
frequency range used for acoustic emission testing, from about 20 kHz to 1 MHz,
whereby the sensor is stimulated by a particle velocity pulse in normal direction to
the sensor’s face from a directly coupled piezoelectric transmitter; and (b) a method
of determining a transmitter’s transmitting sensitivity spectrum in absolute units of
millimeter per second output per unit of volt input, by measuring both, the particle
velocity pulse over the transmitter’s active face and the transmitter’s input voltage
spectrum, by using measurement channels of common frequency characteristics as
offered by a hireable scanning laser vibrometer.
This document does not include the effects on a sensor’s response, when the length
of the wave passing across the sensor’s sensitive face is shorter than about 5 times
of the dimension of the sensor’s sensitive face.”
3.3 Other Chapters
Three mandatory chapters (Chaps. 2–4) concern: Normative references, Terms and
definitions, Symbols and abbreviations.
Chapter 5 describes the face-to-face setup (F2F), which is used to determine the
SUT’s receiving sensitivity, and the laser vibrometer setup (LVM), which is used to
determine the transmitter’s transmitting sensitivity.
Chapter 6 defines all requirements on the hardware described in Chap. 5.
Chapter 7 “Determination of the receiving sensitivity” contains subchapters
“7.1 Scaling of FFT results”, “7.2 Interpolation of time series data of 8–25 ns
sampling interval”, “7.3 DC offset compensation”, “7.4 Recommended stimulation
signal”, “7.5 Windowing of SUT responses”, “7.6 Relevant spectra for sensor sensitivity determination”, “7.7 Formulae for obtaining sensitivities and F2F velocity”,
“7.8 Examples of velocity sensitivity spectra” (of a wideband, a narrowband and