I would like to measure the crack size of plates (i.e., CT under fatigue loading) once I remove them from the testing equipment (they are unloaded).
In my case, the crack is very small (the crack length is in the order to few mm and the opening mouth displacement in the order of 0.1 mm). When I remove the samples from the testing equipment, the fractured surfaces tightly "merge" and the cracking is not easily quantifiable.
Is there an easy and quick way to highlight the fractured surfaces even if they are tightly coupled? I tried by marking the cracking area with a colored marker, but it is still very hard to quantitatively assess the crack length, with a reasonable accuracy.
Many thanks in advance for your help.
Hi
If the cracks in a mm scale, therefore, you can used an optical light microscope or a magnifying lens to determine the crack size.
If the cracks still not visible with the optical light microscope or the magnifying lens, you can use a liquid penetrant technique with a magnifying lens to determine the size of the cracks. The liquid penetrant technique is a non-destructive technique(NDT) for detecting cracks in solid surfaces
Refer to the link on the liquid penetrant technique:
(https://www.google.com/search?biw=1366&bih=651&tbm=isch&sa=1&ei=A1RQW_KjNZGzsAfl86WoBQ&q=The+NDT+liquid+penetrant+technique&oq=The+NDT+liquid+penetrant+technique&gs_l=img.12...12095.19995.0.22306.18.17.1.0.0.0.313.2357.0j1j8j1.10.0....0...1c.1.64.img..9.0.0....0.YuMH0TwT9kk )
Good luck
Thanks a lot for your help.
I am looking into that I think I will probably solve my issue with that.
Regards,
Danilo
Dear Danilo D'Angela, The detection of a crack and their size can be detected at least in two ways. If the material is a metal, a metallographic paste can be applied to the test area. In case of tensioning between the two ends where there are cracks, the fine metal particles accumulate by closing the current circuit. The magnitude of cracks can be measured. Another way to detect the cracks is by spraying with "Diffu-Therm-Diffusions-Rot" spray (1), which absorbs from 5 to 30 minutes in the cracks. Then wash the surface and spray with "Diffu-Therm-DBP Entwickler Developer Revelateur" or Developer White "waiting for 5 to 30 minutes, red lines where there are cracks. measure.
Wishing for success in scientific research. Emil Yankov
Dear Dr/Prof Yankov,
Many thanks for your help.
Your response has been so clear and complete.
I will surely consider your options since they look very suitable and easy to implement. Thanks for the products suggestion.
Good luck with your research too!
Best regards,
Danilo
I would suggest to use Metal magnetic memory test (If sample is made of ferromagnetic material)
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