Week 2

We are glad to communicate: it works! In contrast to last lab classes, this time everything went well. Nevertheless, we start this report (as it was announced recently) by placing the photo of the measurement site.

Measurement site
<<click to enlarge>>

In the foreground, there you can see the ultrasonic flaw detector CUD 10 (between the monitor and the keyboard). There are also cylindrical metal specimens, printed manual, water bottle, piezoelectric heads (on the blue notebook) and two racks (holders). In the background, there is visible older version of the ultrasonic detector but we don’t need it. As it was mentioned last week, the detailed description of the equipment will be given soon in separated news.

Concerning the progress made this week we can say that we are quite satisfied. The planned exchange of the computers was realized without any problem and all software was installed successfully. We have managed to run the first measurements which is encouraging for the future. However, the beginning wasn’t easy because the device manual it not helpful in many cases.

The measurement using ultrasonic flaw detector CUD 10 requires setting material of the sample and type of currently plugged head. Our device has built-in data base with different types of both. For the first test we chose normal head generating longitudinal waves. The sample was made of aluminium. To provide proper transmission of ultrasonic waves from the head to the sample we used water as a coupling liquid.  Additionally we tried to observe what happens in case when the coupling fluid is removed. The results were quite surprising. We expected significant attenuation of recorded signal (due to scattering of waves on the rough surface of the specimen) but there was no signal at all! It’s very valuable experience. On the ground of this observation Justyna figured out that it’s worth checking the influence of different coupling liquids on the recorded signal.

Actually, to be more strict, our measurement wasn’t fully controlled. The choice of the head and the specimen was determined by available data in detector’s register. There’s only a few files with necessary information so we need to download missing data to be able to use all of our heads and samples. If it would occur impossible, we plan to calibrate heads using method described in the manual. The problem regarding the specimens is more complicated because we don't know its composition. If we don’t find any notes about it, we will try to measure the speed of sound in each sample and compare results with the values published in literature to recognize the material.