where expertise comes together - since 1996 -

The Largest Open Access Portal of Nondestructive Testing (NDT)

Conference Proceedings, Articles, News, Exhibition, Forum, Network and more

where expertise comes together
- since 1996 -

626 views
Technical Discussions
Rolf Diederichs
Director,
NDT.net, Germany, Joined Nov 1998, 604

Rolf Diederichs

Director,
NDT.net,
Germany,
Joined Nov 1998
604
00:44 May-12-1997
Model generated by an inverse Fast Fourier Transformation

Concerning the article "Approximative Modeling for the Practical Ultrasonic Inspections" by H.Wüstenberg, A.Erhard.
The A-Scans are in the model generated by an inverse Fast Fourier Transformation.
What are the advantages and drawbacks of this approach?

Rolf Diederichs



    
 
 
Hermann Wuestenberg
R & D
BAM Berlin, Germany, Joined Nov 1998, 26

Hermann Wuestenberg

R & D
BAM Berlin,
Germany,
Joined Nov 1998
26
06:37 May-16-1997
Re: Model generated by an inverse Fast Fourier Transformation
: Concerning the article "Approximative Modeling for the Practical Ultrasonic Inspections" by H.Wüstenberg, A.Erhard.
: The A-Scans are in the model generated by an inverse Fast Fourier Transformation.
: What are the advantages and drawbacks of this approach?

: Rolf Diederichs


Pleas find here an first attempt of answering the following question:

1. The model can be linked to well known pulse spectra of UT-probes,
which commonly are available as data measured and also - depending
from the manufacturer - calculated by a KLM-quadrupol model or
similar equivalent circuits for the probe. The influence of the
bandpass filter characteristic of the receiving amplifier within the
UT-equipment can easely be studied.

2. The phase behaviour of reflection or mode conversion factors and of
the point source directivities for the different wave modes and its
influence can be considered without any difficulty

3. This enables us to cut the totality of the process into different
parts and to multiply or add them in order to get the transfer
function of the whole system.

4. The necessary number of frequency samples to be calculated can be
adapted to the extension of the time domain to be considered for the
A-Scan. E.g. many of the examples in the above mentioned contribution
are using 64 samples in the frequeny domain and 128 in the time
domain, which corresponds e.g. to 16 mm sound path length. That means
that the use of the inverse FFT enables us to reach very short
computational times.


The drawbacks have to listed by someone else favorising a time domain
approach.

greetings

and Frohe Pfingsten

Hermann Wuestenberg



    
 
 

Product Spotlight

High-performance Linear Phased Array Probes

Available to order from stock in a range of 5MHz – 7.5MHz and from 16 to 64 elements. Designed w
...
ith piezo-composite elements, Phoenix phased array probes provide high-resolution imaging to maximise sensitivity; accurate ultrasonic detection and sizing of defects in welds; and effective corrosion mapping. Housed in a rugged stainless steel case for on-site industrial NDT applications.
>

Research Center IDEKO develops an ultrasonic train wheel inspection system for CAF

The Basque Research centre IK4-IDEKO has developed a state-of-the-art ultrasonic inspection system f
...
or the train wheel. This system secures a sound condition of train wheels and is thus a significant contribution to rail transport safety. The device was delivered to CAF recently and its use allows the manufacturer to become an approved supplier of rolling stock in Italy, as it meets the demanding homologation standards of this country. \\\\r\\\\n
>

FlexoFORM™

The FlexoFORM™ solution integrates flexible phased array probe technology in a scanner to solv
...
e the challenges that come with inspecting pipe elbows. When combined with a water column, this solution can be used to collect easy-to-interpret data on elbows with diameters ranging from 4.5 in. OD up to flat and offers many benefits.
>

Robotic laser shearography enables 100% inspection of complex, flight-critical composite structures

An article in “Composites World Magazine” showcases Non Destructive Testing of aero-structures
...
with Laser Shearography. Over the years Dantec Dynamics has supplied many solutions for the aerospace industry. Referring to specific customer projects several of these cases are examined to outline the advantages of using Laser Shearography for automated defect detection.
>

Share...
We use technical and analytics cookies to ensure that we will give you the best experience of our website - More Info
Accept
top
this is debug window