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DMTA-10084-01EN, Rev. 2, November 2018
Chapter 11
180
This curve-height adjustment is possible because the DGS/AVG curves are calculated
based on a captured reference reflector and mathematical probe data. This allows the
EPOCH 6LT to plot the attenuation curve (in steel) for a particular reflector size
without having to acquire individual data points, as is required in a DAC/TCG setup.
This is one of the key advantages of the DGS/AVG sizing technique over the
DAC/TCG sizing technique.
To adjust the registration level
1.
Open the
DGS/AVG
submenu, and then press the Tab key to select
Reg Level
.
2.
Turn the adjustment knob, and then press the Enter key to adjust the current
registration-level value.
11.4.6
Relative Attenuation Measurement
There are several methods for measuring the ultrasonic attenuation within a material.
Often the procedure measures absolute attenuation in a material. This usually
requires an immersion test setup and a time-consuming set of measurements. For the
purpose of flaw sizing with the DGS/AVG method, it might be suitable in many cases
to measure relative attenuation in the test piece or calibration block as needed. This
section outlines one simple method of relative attenuation measurement, which is
generally effective. There may be a more suitable method available. You must decide
the most appropriate method to arrive at the values for ACV Specimen and ACV Cal
Block based on the application and local requirements.
Measurements:
∆
Vg
= Gain difference between two successive back wall echoes (d and 2d)
∆
Ve
= Gain difference on back wall curve from d to 2d
Calculations:
∆
Vs
=
∆
Vg
−
∆
Ve
[dB]
Sound attenuation coefficient:
NOTE
Содержание EPOCH 6LT
Страница 8: ...DMTA 10084 01EN Rev 2 November 2018 Table of Contents viii...
Страница 10: ...DMTA 10084 01EN Rev 2 November 2018 List of Abbreviations x...
Страница 16: ...DMTA 10084 01EN Rev 2 November 2018 Introduction 6...
Страница 20: ...DMTA 10084 01EN Rev 2 November 2018 Chapter 1 10...
Страница 26: ...DMTA 10084 01EN Rev 2 November 2018 Chapter 2 16...
Страница 32: ...DMTA 10084 01EN Rev 2 November 2018 Chapter 3 22...
Страница 68: ...DMTA 10084 01EN Rev 2 November 2018 Chapter 5 58 Figure 5 15 Diagnostic Test setup page...
Страница 109: ...DMTA 10084 01EN Rev 2 November 2018 Calibration 99 Figure 8 7 Calibration Successfully completed...
Страница 110: ...DMTA 10084 01EN Rev 2 November 2018 Chapter 8 100...
Страница 154: ...DMTA 10084 01EN Rev 2 November 2018 Chapter 9 144...
Страница 216: ...DMTA 10084 01EN Rev 2 November 2018 Chapter 11 206 Figure 11 45 Corrosion sidebar menu G2Start...
Страница 220: ...DMTA 10084 01EN Rev 2 November 2018 Appendix 210...
Страница 226: ...DMTA 10084 01EN Rev 2 November 2018 List of Tables 216...
Страница 232: ...DMTA 10084 01EN Rev 2 November 2018 Index 222...