Time of Flight Diffraction (ToFD)
Time-of-flight diffraction (TOFD) method of ultrasonic testing is a sensitive and accurate method for the... View more
TOFD signals between L-L Backwall and L-Shear Backwall echo.
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TOFD signals between L-L Backwall and L-Shear Backwall echo.
In a TOFD image it is recommended (ASME for example) a complete TOFD image including also the shear diffracted signals.
Where can I find clear and practical guidelines to make decissions and to understand the signals which appears between the Long- Long backwall echo and the Long-Shear backwall echo?
Thanks in advance. -
1 Reply
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I do not know if there is an absolute method for this. In the book by Charlesworth and Temple there is an image (Figure 5-8) that shows all the arcs for the Compression, Shear and Rayleigh modes and indicates the top and bottom signals for a single planar flaw. This image is a VERY confusing “mess” to look at.
The authors state that “…it may be necessary to make a judgement as to which are the unconverted compression wave signals from the top and bottom of the defect and then calculate the positions and curve-shapes of all possible mode converted signals.”
