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Acoustic Emission Consulting, Inc.
Acoustic Emission Consulting, Inc. specializes in the design of small portable AE instruments for field and lab use.
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Technical Discussions
Roman
Engineering,
Mechanics of Adaptive Systems, Germany, Joined Jan 2018, 4

Roman

Engineering,
Mechanics of Adaptive Systems,
Germany,
Joined Jan 2018
4
10:01 Jan-11-2018
Ultrasonic Testing on Rocks

Dear all,

I am working on the ultrasonic testing of rocks for research on tunnel exploration.
We developed inversion methods to detect changes in the material, and now we want to relate it to experimental data.

By now I am trying to reproduce the experimentally obtained time domain data by simulation.
This works quite well for aluminium blocks, but for rocks it was not possible at all by now. I tried it on blocks of sandstone and granite with frequencies of about 50 kHz. Material models are simplified by taking a homogeneuous and isotropic model with experimentally obtained wavespeeds.

Can anyone tell me if it is possible for sandstone and granite to get good simulation results compared to the experimental data? Are there rocks for which it is easier?


Thank you and best regards,

Roman

 
 Reply 
 
Anmol Birring
Consultant,
Birring NDE Center, Inc., USA, Joined Aug 2011, 805

Anmol Birring

Consultant,
Birring NDE Center, Inc.,
USA,
Joined Aug 2011
805
14:57 Jan-11-2018
Re: Ultrasonic Testing on Rocks
In Reply to Roman at 10:01 Jan-11-2018 (Opening).

I think you should look at seismic tests used for oil exploration. They are quite advanced

 
 Reply 
 
Ed Ginzel
R & D, -
Materials Research Institute, Canada, Joined Nov 1998, 1300

Ed Ginzel

R & D, -
Materials Research Institute,
Canada,
Joined Nov 1998
1300
16:04 Jan-11-2018
Re: Ultrasonic Testing on Rocks
In Reply to Roman at 10:01 Jan-11-2018 (Opening).

Roman, there is a group in civil engineering at the University of Waterloo that has been working on ultrasonic pulse-velocity assessments in rock and concrete. You might try contacting the supervising professor (Giovanni Cascante [gcascante@uwaterloo.ca]). I know several of the researchers there have been using Comsol. A group in Norway also used Comsol in part of their work simulating sandstone...see https://arxiv.org/ftp/arxiv/papers/1604/1604.02255.pdf

 
 Reply 
 
Rolf Diederichs
Director,
NDT.net, Germany, Joined Nov 1998, 616

Rolf Diederichs

Director,
NDT.net,
Germany,
Joined Nov 1998
616
16:59 Jan-11-2018
Re: Ultrasonic Testing on Rocks
In Reply to Roman at 10:01 Jan-11-2018 (Opening).

EWGAE 2012
http://www.ndt.net/?id=13595
Acoustic Emission and Ultrasonic Transmission Monitoring of Hydraulic Fracture Initiation and Propagation in Rock Samples
S. Stanchits, A. Surdi, E. Edelman, R. Suarez-Rivera
TerraTek A Schlumberger Company, Salt Lake City, UT [USA]

You can find more papers in the database. Most of the research is done by AE methods.

 
 Reply 
 
Roman Rettich
Engineering,
Mechanics of Adaptive Systems, Germany, Joined Jan 2018, 4

Roman Rettich

Engineering,
Mechanics of Adaptive Systems,
Germany,
Joined Jan 2018
4
14:42 Jan-15-2018
Re: Ultrasonic Testing on Rocks
In Reply to Rolf Diederichs at 16:59 Jan-11-2018 .

Thank you very much for your hints!!
Most of the papers only do concern about arrival times and wave speeds, unfortunately I did not find any paper which concerns about full reconstruction of the waveforms.

Maybe anyone still got some more hints?

 
 Reply 
 
Henry
Henry
18:19 Jan-15-2018
Re: Ultrasonic Testing on Rocks
In Reply to Roman Rettich at 14:42 Jan-15-2018 .

Roman, you could have a look at the full-waveform inversion method from seismic exploration. You will need to build the velocity model first. There is plenty of information on full waveform inversion in geophysics. You will also find ready to use scripts.

 
 Reply 
 
Simon Amallraja
Simon Amallraja
07:24 Jan-16-2018
Re: Ultrasonic Testing on Rocks
In Reply to Roman at 10:01 Jan-11-2018 (Opening).

You can try with RPR 4000 Tone burst PR unit (from RITEC USA) with some Gas Matrix NCU probes of 140 to 250 kHz (from Ultran Group USA) for this application.
The PR unit generates high voltage and energy up to 15 KW RMS. This should help in penetrating these materials

 
 Reply 
 
Roman Rettich
Engineering,
Mechanics of Adaptive Systems, Germany, Joined Jan 2018, 4

Roman Rettich

Engineering,
Mechanics of Adaptive Systems,
Germany,
Joined Jan 2018
4
09:41 Jan-16-2018
Re: Ultrasonic Testing on Rocks
In Reply to Simon Amallraja at 07:24 Jan-16-2018 .

Thank you!!
I know FWI and we are also getting signals which are strong enough and which are reproducible when we repeat the measurement.
The problem is that I think we do not have a chance if the experimental waveforms and the simulated waveforms look completely different.
Maybe one has to adapt the material models (except of varying velocities), but the question is how!? Do you think I should bring in anisotropy and porosity?

 
 Reply 
 
Henry
R & D,
UT Quality, Canada, Joined Jun 2000, 19

Henry

R & D,
UT Quality,
Canada,
Joined Jun 2000
19
18:23 Jan-16-2018
Re: Ultrasonic Testing on Rocks
In Reply to Roman Rettich at 09:41 Jan-16-2018 .

Roman, this paper could be useful
Anisotropic 3D full-waveform inversion
https://www.cgg.com/technicalDocuments/cggv_0000014292.pdf

See the steps in the FWI workflow. I don't think you will have a perfect match between experimental and simulated waveform without including anisotropy. The other critical step is building the source wavelet. Read comments on step 6 on the paper. How do you build the wavelet for you synthetic data?

regards,

 
 Reply 
 
Roman Rettich
Engineering,
Mechanics of Adaptive Systems, Germany, Joined Jan 2018, 4

Roman Rettich

Engineering,
Mechanics of Adaptive Systems,
Germany,
Joined Jan 2018
4
18:37 Jan-16-2018
Re: Ultrasonic Testing on Rocks
In Reply to Henry at 18:23 Jan-16-2018 .

Thank you, this seems like a useful hint. I will get through the paper in the next days.

I estimate my source wavelet by comparing measured data and experimental data in the frequency domain. I simply divide measurement data by simulation data and multiply it with the input wavelet.
This works quite well for aluminium. But because time domain data of experiment and simulation look so different for soil, I have no chance there...

 
 Reply 
 
Henry
R & D,
UT Quality, Canada, Joined Jun 2000, 19

Henry

R & D,
UT Quality,
Canada,
Joined Jun 2000
19
20:24 Jan-16-2018
Re: Ultrasonic Testing on Rocks
In Reply to Roman Rettich at 18:37 Jan-16-2018 .

Roman, it seems that you have a problem with your inverse filter then. This looks like a classic deconvolution problem and it works well for aluminum because the SNR is high. For noisy signals is unstable. Instead of dividing the spectrum you have to use the Wiener filter or any variant of optimal filtering.
Please have a look at this work I did some time ago:

http://www.ndt.net/events/NDTCanada2015/app/content/Paper/8_Herrera_Rev1.pdf

Note that the wavelet could be statistically estimated from the experimental data as well.

Regards,
Henry

 
 Reply 
 

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