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Technical Discussions
Wolfgang Holstein
Wolfgang Holstein
09:33 May-13-2003
looking for wind turbine blade testing method

Rotorblade ND-testing quality today is a question of inspectors level of educated guess. Conventional tap testing method is best today. Does anyone have better (objective) techniques? Are there experiences with electronic tap tester (woodpecker)?
Thanks for wisdom.


    
 
 
Jörg Collrep
Jörg Collrep
00:27 May-13-2003
Re: looking for wind turbine blade testing method
The shearogarphy method is a good candidate for testing debondings and separations in this kind of parts. Shearogarphy has successfully proofed it's capabilities in aerospace CFRP components. See more details also on: www.syncretek.com.
Very fast and easy to handle technology. Pls contact us for more details

: Rotorblade ND-testing quality today is a question of inspectors level of educated guess. Conventional tap testing method is best today. Does anyone have better (objective) techniques? Are there experiences with electronic tap tester (woodpecker)?
: Thanks for wisdom.
.



    
 
 
Jens Forker
Jens Forker
01:14 May-13-2003
Re: looking for wind turbine blade testing method
AE testing has been used with good success on composite rotor blades. Email me for more discussion or see our website for info on AE.
A starting point could be the standard ASTM E 2076: Standard Test Method for the Examination of Fiberglass Reinforced Plastic Fan Blades using Acoustic Emission.
regards
Jens

: Rotorblade ND-testing quality today is a question of inspectors level of educated guess. Conventional tap testing method is best today. Does anyone have better (objective) techniques? Are there experiences with electronic tap tester (woodpecker)?
: Thanks for wisdom.
.



    
 
 
Rolf Diederichs
Director,
NDT.net, Germany, Joined Nov 1998, 604

Rolf Diederichs

Director,
NDT.net,
Germany,
Joined Nov 1998
604
02:19 May-13-2003
Re: looking for wind turbine blade testing method
I could find these two articles at NDT.net:

Real-Time Evaluation Of Wind Turbine Blades With Acoustic Emission Monitoring During Certification Tests
http://www.ndt.net/article/v07n09/12/12.htm
in NDT.net - September 2002, Vol. 7 No.09


Acoustic Emission Monitoring from Wind Turbine Blades Undergoing Static and Fatigue Testing
http://www.ndt.net/article/wcndt00/papers/idn553/idn555.htm
15th WCNDT CD-ROM

Rolf Diederichs

----------------
: Rotorblade ND-testing quality today is a question of inspectors level of educated guess. Conventional tap testing method is best today. Does anyone have better (objective) techniques? Are there experiences with electronic tap tester (woodpecker)?
: Thanks for wisdom.
.



    
 
 
Robert Paynter
Robert Paynter
02:50 May-13-2003
Re: looking for wind turbine blade testing method
: Rotorblade ND-testing quality today is a question of inspectors level of educated guess. Conventional tap testing method is best today. Does anyone have better (objective) techniques? Are there experiences with electronic tap tester (woodpecker)?
: Thanks for wisdom.

How big are the blades? - I've seen 40cm to 40m
How complex is the internal structure?

I suspect that the only accurate way would be by UT using a D-scan checked against expected times of flight through the skins. For a typical wind turbine blade the structure will include webs, foam sandwich, various changes in the layup - not simple, but it should be possible to choose critical parts.

The time it takes to do such a scan might be too much but with a well set up automated system it might be OK.

If you want an opinion on the applicability of acoustic emmision ask the Energy Research Unit at Rutherford Appleton Lab (ttp://www.eru.rl.ac.uk/current_projects.htm)

A "full field" measurement would be good to direct detailed UT examination. You could use Thermoelasticity or Shearography (as suggested by another response); my experience is with thermoelasticity applied to Wind Turbine Blades (4.5 and 13m long) in research setting. It's hard work to set up for large objects - but possible.

Good luck,

Robert


    
 
 
Steve Alderton
Steve Alderton
03:13 May-13-2003
Re: looking for wind turbine blade testing method
There is an X-ray technique for the inspection of new composite blades at the point where steel incerts are bonded, we have sold dedicated equipment for this purpose. If you need further details contact me direct.

: AE testing has been used with good success on composite rotor blades. Email me for more discussion or see our website for info on AE.
: A starting point could be the standard ASTM E 2076: Standard Test Method for the Examination of Fiberglass Reinforced Plastic Fan Blades using Acoustic Emission.
: regards
: Jens
.
: : Rotorblade ND-testing quality today is a question of inspectors level of educated guess. Conventional tap testing method is best today. Does anyone have better (objective) techniques? Are there experiences with electronic tap tester (woodpecker)?
: : Thanks for wisdom.
: .
.



    
 
 
Athanasios Anastasopoulos
Director,
Mistras Group, Greece, Joined Jan 2000, 14

Athanasios Anastasopoulos

Director,
Mistras Group,
Greece,
Joined Jan 2000
14
03:26 May-13-2003
Re: looking for wind turbine blade testing method
Application of AE for full scale testing of Wind Turbine Blades started In USA, at Sandia Labs, and relevant reports exist at Sandia web site by Dr. Alain Beattie who successfully demonstrated the use of AE.
Later on and at a European Level we worked with key organizations and institutions in developing AE methodologies for WT blades testing. Within this framework dedicated s/w for grading damage in WT blades by means of AE was developed (visit the http://www.envirocoustics.gr/eng_eng.htm to have an idea of the s/w screens)
Further info about the EU project entitled “Acoustic Emission Proof Testing and Damage Assessment of Wind Turbine Blades (AEGIS) funded by European Commission [JOR3-CT98-0283], September 1998 to October 2002” can be found at the project web page: http://www.eru.rl.ac.uk/AEGIS/aegis.htm
From the link above you can also download the following articles:
Acoustic emission monitoring for wind turbine blades undergoing static and fatigue testing, Proceedings of 15th World Conference on Non-Destructive Testing, Roma, October 2000 (PDF: 187kB, 7 pages)
Acoustic Emission Monitoring During Certification Testing Of Wind Turbine Blades, Proceeding of the 2001 European Wind Energy Conference, Copenhagen, July 2001 (PDF: 110kB, 4 pages)
Acoustic Emission Monitoring of Small Wind Turbine Blades, AIAA_2002_0063, Proceeding of the 21st ASME Wind Energy Symposium, Reno, USA, 14-17, January 2002 (PDF: 394kB, 11 pages)
Damage Classification of Acoustic Emission using Aegis Pattern Recognition Software from Ten Small Wind Turbine Blade Tests, Proceeding of Global Windpower, Paris, April 2002 (PDF: 278kB, 5 pages)
Real-time evaluation of wind turbine blades with acoustic emission monitoring during certification tests, NDT.net, NDT.net - Special Issue on Acoustic Emission, September 2002, Vol. 7 No.09
Structural integrity evaluation of wind turbine blades using pattern recognition analysis on acoustic emission data, The 25th European Conference on Acoustic Emission Testing - EWGAE 2002, Prague, Czech Republic, 11–13 September 2002 (PDF: 176kB, 8 pages)
P.A. Joosse, M.J. Blanch, A.G. Dutton, D. Kouroussis, T.P. Philippidis, P. Vionis, Acoustic Emission Monitoring of Small Wind Turbine Blades, JSEE Paper No. 10/2-112, Vol. 124, pp 446-454, November 2002. (Abstract only PDF: 63kB, 1 page; Full paper available from: ASME on-line store)
Should you need further info about AE on WT blades or in general full scale testing of WT blades please contact me at nassos@envirocoustics.gr

: Rotorblade ND-testing quality today is a question of inspectors level of educated guess. Conventional tap testing method is best today. Does anyone have better (objective) techniques? Are there experiences with electronic tap tester (woodpecker)?
: Thanks for wisdom.
.



    
 
 
Athanasios Anastasopoulos
Director,
Mistras Group, Greece, Joined Jan 2000, 14

Athanasios Anastasopoulos

Director,
Mistras Group,
Greece,
Joined Jan 2000
14
03:34 May-13-2003
Re: looking for wind turbine blade testing method
Please note that fan blades are of different design compared with WT blades. In addition to that WT blades are designed for different working loads than fan blades (even WT blade certification requirements might vary depending on the installation site).
Our research (“Acoustic Emission Proof Testing and Damage Assessment of Wind Turbine Blades (AEGIS) funded by European Commission [JOR3-CT98-0283], September 1998 to October 2002” can be found at the project web page: http://www.eru.rl.ac.uk/AEGIS/aegis.htm ) and our experience shows that the aforementioned ASTM standard for fan blades is not suitable for AE testing of WT Blades. Should you need help, please contact me by e-mail.

: AE testing has been used with good success on composite rotor blades. Email me for more discussion or see our website for info on AE.
: A starting point could be the standard ASTM E 2076: Standard Test Method for the Examination of Fiberglass Reinforced Plastic Fan Blades using Acoustic Emission.
: regards
: Jens
.
: : Rotorblade ND-testing quality today is a question of inspectors level of educated guess. Conventional tap testing method is best today. Does anyone have better (objective) techniques? Are there experiences with electronic tap tester (woodpecker)?
: : Thanks for wisdom.
: .
.



    
 
 
Wolfgang Bisle
R & D, Project leader & Group Leader InService Inspect.
Airbus Deutschland GmbH, Germany, Joined Jul 2000, 35

Wolfgang Bisle

R & D, Project leader & Group Leader InService Inspect.
Airbus Deutschland GmbH,
Germany,
Joined Jul 2000
35
05:49 May-16-2003
In Service inspections of wind turbine blade
I don't think that Acousitc Emmission testing will be a feasable technique for In-Sevice inspections (except it would be included as a health monitoring system in the blade, but under commercial aspects this would be - with todays systems - much too expensive). It is even not qualified for this (in the means of a qualification process as it is do for instance in the aeronautics)

Shearography might look attractive, but remember you need a technique to load the structure. In most cases it is more or less impossible to check structures thicker then 8 mm with current available techniques. Then the stiffness of a FRP-structure will not give enough response to the load. For handling thermal load is today the easiest, but penetration depth of heat is limited. Applying vacuum needs heavy chambers to apply and even here the 8mm is more or less a limit today.

Thermography (pulsed or lock-in) might result in similar detection capabilities and limits for fiberplastics - thats until now the experience in aeronautics.

In case of using vibration loading (for shearography as well as for Thermography (here ultrasonic burst excitated phase thermography according to Prof. Busse, IKP) might lead to improved capabilities, still this is in a research phase.

X-Ray seems to be not feasable, because of security reasons, handling reasons and typically delamination cannot be detected. If you look into commercial aviation it is normally not used for InService inspections of FRP's.

What is left?

Mainly acoustic methods.
The taptest is a primitive but quiet effectfull way to check FRP structures. It is the first choice for a first step.
To overcome the primitivity the Mitsui Woodpecker is the further step to decrase the human factor; the next step would be the CATT (computer aided tap test)from CNDE now sold by Advanced Structural Imaging, Inc.
If this instrument could be combined with a mapping technology used in the Ultrasonic inspection instrument ISONIC from SONOTRON NDT (Israel) - this is an acoustic triangulationsystem for position mapping - it would be perfect.

The same would mnecessary be if using the Staveley Bondmaster - as for such huge structures a mapping technology is essential.

Mapping is also essential to overcome problems with interpretation of signals if you have not an exact layup-plan of the FRP-layers. Otherwise you get lost in echoes or resonances. This is still - as it was told to me - a major draw-back, because the manufacturers don't offer access to their drawings to independent inspectors.

Currently in the aeronautics there is a switch from simple ultrasonic equipment to array or phased array inspection systems. But for In-Service Inspection purposes currently only one canadian company (is it the market leader? - you see their system everywhere) offers a system (Omniscan from RD-tech) which will fit the needs (if once in hopefully near future the software would have left the Beta-Version state). These array systems - for this inspection case mostly used in paintbrush array probe configuration - offer lot more insights to the complex structure then every other isntrument. Question: Are for all needs suitable low-frequency arrays on the market? But this will come!

With our current experience mechanical scanners are more or less out. Too much efford to set up. Too much occasions to fail and fall.

What about Vibrometer and acoustic excitation with a sound gun. Under the label of SAM & RAID an interesting setup is now promoted by honeywell. Up to now they sell it as a closed box solution for aircraft testing - for which I am sceptical because of its worth. but the technique itself could be a good platform even for the Wind mill problem.
Let's see if Honeywell picks this up.

Still I think inspecting these rotorblades will be a key issue for the wind enegy industry, as in the near past a lot of wind mills broke down because of structural problems. It seems that the factor structure inspection up to now did not play the role it should have. Or is there already set up a standard for the qualification / training of inspection personal like it is done elsewhere (like EN4179 or NAS410, which are the standards for aerospace, and I guess that they would fit best because of similar materials and problems). Are there nondestructive testing procedures laid down to guide an inspector, how to deal with these complex materials?

What will happen if these propellers work offshore? In a harsh environment? Maybe a failure would not be as fatal as with a rotor just 20 meters beneath a motorway.

Let's see what happens....


    
 
 
Gary Penney
Consultant
TWI, United Kingdom, Joined May 2001, 15

Gary Penney

Consultant
TWI,
United Kingdom,
Joined May 2001
15
09:00 May-17-2003
Re: In Service inspections of wind turbine blade
I do not believe there is a whole lot to say on this subject as Wolfgang has summarised the current state of the art in an excellent manner.

I have recently submitted a 2m Euro CRAFT project, the work programme of which could frankly of been written from Wolfgang,s summary.

We will not know if the proposal will be accepted for a few months but obviously there is a lot of concern in the community surrounding this topic. Consequently we will more than likely try and submit further proposals for large projects in this field, to that end any ideas for particular areas to attack would be more than welcome.

Regards

Gary


: I don't think that Acousitc Emmission testing will be a feasable technique for In-Sevice inspections (except it would be included as a health monitoring system in the blade, but under commercial aspects this would be - with todays systems - much too expensive). It is even not qualified for this (in the means of a qualification process as it is do for instance in the aeronautics)
.
: Shearography might look attractive, but remember you need a technique to load the structure. In most cases it is more or less impossible to check structures thicker then 8 mm with current available techniques. Then the stiffness of a FRP-structure will not give enough response to the load. For handling thermal load is today the easiest, but penetration depth of heat is limited. Applying vacuum needs heavy chambers to apply and even here the 8mm is more or less a limit today.
.
: Thermography (pulsed or lock-in) might result in similar detection capabilities and limits for fiberplastics - thats until now the experience in aeronautics.
.
: In case of using vibration loading (for shearography as well as for Thermography (here ultrasonic burst excitated phase thermography according to Prof. Busse, IKP) might lead to improved capabilities, still this is in a research phase.
.
: X-Ray seems to be not feasable, because of security reasons, handling reasons and typically delamination cannot be detected. If you look into commercial aviation it is normally not used for InService inspections of FRP's.
.
: What is left?
.
: Mainly acoustic methods.
: The taptest is a primitive but quiet effectfull way to check FRP structures. It is the first choice for a first step.
: To overcome the primitivity the Mitsui Woodpecker is the further step to decrase the human factor; the next step would be the CATT (computer aided tap test)from CNDE now sold by Advanced Structural Imaging, Inc.
: If this instrument could be combined with a mapping technology used in the Ultrasonic inspection instrument ISONIC from SONOTRON NDT (Israel) - this is an acoustic triangulation system for position mapping - it would be perfect.
.
: The same would mnecessary be if using the Staveley Bondmaster - as for such huge structures a mapping technology is essential.
.
: Mapping is also essential to overcome problems with interpretation of signals if you have not an exact layup-plan of the FRP-layers. Otherwise you get lost in echoes or resonances. This is still - as it was told to me - a major draw-back, because the manufacturers don't offer access to their drawings to independent inspectors.
.
: Currently in the aeronautics there is a switch from simple ultrasonic equipment to array or phased array inspection systems. But for In-Service Inspection purposes currently only one canadian company (is it the market leader? - you see their system everywhere) offers a system (Omniscan from RD-tech) which will fit the needs (if once in hopefully near future the software would have left the Beta-Version state). These array systems - for this inspection case mostly used in paintbrush array probe configuration - offer lot more insights to the complex structure then every other isntrument. Question: Are for all needs suitable low-frequency arrays on the market? But this will come!
.
: With our current experience mechanical scanners are more or less out. Too much efford to set up. Too much occasions to fail and fall.
.
: What about Vibrometer and acoustic excitation with a sound gun. Under the label of SAM & RAID an interesting setup is now promoted by honeywell. Up to now they sell it as a closed box solution for aircraft testing - for which I am sceptical because of its worth. but the technique itself could be a good platform even for the Wind mill problem.
: Let's see if Honeywell picks this up.
.
: Still I think inspecting these rotorblades will be a key issue for the wind enegy industry, as in the near past a lot of wind mills broke down because of structural problems. It seems that the factor structure inspection up to now did not play the role it should have. Or is there already set up a standard for the qualification / training of inspection personal like it is done elsewhere (like EN4179 or NAS410, which are the standards for aerospace, and I guess that they would fit best because of similar materials and problems). Are there nondestructive testing procedures laid down to guide an inspector, how to deal with these complex materials?
.
: What will happen if these propellers work offshore? In a harsh environment? Maybe a failure would not be as fatal as with a rotor just 20 meters beneath a motorway.
.
: Let's see what happens....
.



    
 
 
Christophe Mattei
Consultant
Exova AB, NDT Dpt., Sweden, Joined Jan 2001, 8

Christophe Mattei

Consultant
Exova AB, NDT Dpt.,
Sweden,
Joined Jan 2001
8
09:01 May-19-2003
Re: In Service inspections of wind turbine blade
Just a general comment on the actual needs for NDE of wind turbine blades. We have recently been in contact with a Scandinavian wind turbine manufacturer and frankly they don't really seem to worry about the integrity of the blades. Their concerns were about the long term performances of the metallic parts (gear box, shaft, etc..). According to them, the blades are overdimensioned since the weight issue is not as critical as in aerospace applications. Moreover there is right now very little legislation about safety since the mills are often located away from urban areas.
Maybe,as Wolfang pointed out, offshore applications will be more critical (with environmental ageing issues and difficult maintenance) but it seems that the only ones interested in wind mill blade inspection are the NDE folks not the manufacturers or companies running the wind mills.
It would be interesting to get reactions from "inside" the wind mill industry.

Christophe Mattei


    
 
 
Athanasios Anastasopoulos
Director,
Mistras Group, Greece, Joined Jan 2000, 14

Athanasios Anastasopoulos

Director,
Mistras Group,
Greece,
Joined Jan 2000
14
00:11 May-19-2003
Re: In Service inspections of wind turbine blade
In addition to the details listing of methods and associated limitations let me add the following:
- AE Health monitoring has been applied during the JOULE project mentioned in previous e-mail. MISTRAS system installed inside the root of the blade and continuous health monitoring was performed.
- An efficient inspection technique, specially developed for thick composites is the so called TSCOUT, developed by Physical Acoustics Corp. www.pacndt.com. It is basically Oblique Angle Acousto-Ultrasonic using long waveforms (through optimized for similar application arbitrary waveform generator board)to excite medium & low frequency AE sensors.
For further details on the 1st item you might contact me by e-mail, while for the 2nd you should contact PAC.

: I don't think that Acousitc Emmission testing will be a feasable technique for In-Sevice inspections (except it would be included as a health monitoring system in the blade, but under commercial aspects this would be - with todays systems - much too expensive). It is even not qualified for this (in the means of a qualification process as it is do for instance in the aeronautics)
.
: Shearography might look attractive, but remember you need a technique to load the structure. In most cases it is more or less impossible to check structures thicker then 8 mm with current available techniques. Then the stiffness of a FRP-structure will not give enough response to the load. For handling thermal load is today the easiest, but penetration depth of heat is limited. Applying vacuum needs heavy chambers to apply and even here the 8mm is more or less a limit today.
.
: Thermography (pulsed or lock-in) might result in similar detection capabilities and limits for fiberplastics - thats until now the experience in aeronautics.
.
: In case of using vibration loading (for shearography as well as for Thermography (here ultrasonic burst excitated phase thermography according to Prof. Busse, IKP) might lead to improved capabilities, still this is in a research phase.
.
: X-Ray seems to be not feasable, because of security reasons, handling reasons and typically delamination cannot be detected. If you look into commercial aviation it is normally not used for InService inspections of FRP's.
.
: What is left?
.
: Mainly acoustic methods.
: The taptest is a primitive but quiet effectfull way to check FRP structures. It is the first choice for a first step.
: To overcome the primitivity the Mitsui Woodpecker is the further step to decrase the human factor; the next step would be the CATT (computer aided tap test)from CNDE now sold by Advanced Structural Imaging, Inc.
: If this instrument could be combined with a mapping technology used in the Ultrasonic inspection instrument ISONIC from SONOTRON NDT (Israel) - this is an acoustic triangulation system for position mapping - it would be perfect.
.
: The same would mnecessary be if using the Staveley Bondmaster - as for such huge structures a mapping technology is essential.
.
: Mapping is also essential to overcome problems with interpretation of signals if you have not an exact layup-plan of the FRP-layers. Otherwise you get lost in echoes or resonances. This is still - as it was told to me - a major draw-back, because the manufacturers don't offer access to their drawings to independent inspectors.
.
: Currently in the aeronautics there is a switch from simple ultrasonic equipment to array or phased array inspection systems. But for In-Service Inspection purposes currently only one canadian company (is it the market leader? - you see their system everywhere) offers a system (Omniscan from RD-tech) which will fit the needs (if once in hopefully near future the software would have left the Beta-Version state). These array systems - for this inspection case mostly used in paintbrush array probe configuration - offer lot more insights to the complex structure then every other isntrument. Question: Are for all needs suitable low-frequency arrays on the market? But this will come!
.
: With our current experience mechanical scanners are more or less out. Too much efford to set up. Too much occasions to fail and fall.
.
: What about Vibrometer and acoustic excitation with a sound gun. Under the label of SAM & RAID an interesting setup is now promoted by honeywell. Up to now they sell it as a closed box solution for aircraft testing - for which I am sceptical because of its worth. but the technique itself could be a good platform even for the Wind mill problem.
: Let's see if Honeywell picks this up.
.
: Still I think inspecting these rotorblades will be a key issue for the wind enegy industry, as in the near past a lot of wind mills broke down because of structural problems. It seems that the factor structure inspection up to now did not play the role it should have. Or is there already set up a standard for the qualification / training of inspection personal like it is done elsewhere (like EN4179 or NAS410, which are the standards for aerospace, and I guess that they would fit best because of similar materials and problems). Are there nondestructive testing procedures laid down to guide an inspector, how to deal with these complex materials?
.
: What will happen if these propellers work offshore? In a harsh environment? Maybe a failure would not be as fatal as with a rotor just 20 meters beneath a motorway.
.
: Let's see what happens....
.



    
 
 
Doug Breeze
Director, Consultant; R&D
Inspection Software Limited, United Kingdom, Joined May 2000, 20

Doug Breeze

Director, Consultant; R&D
Inspection Software Limited,
United Kingdom,
Joined May 2000
20
02:09 May-19-2003
In Service inspections of wind turbine blade
Ultrasonic mapping is likely to be the most valuable method for reproducible precison analysis. FORCE Technology (Denmark) is already very active in this area using automated UT on wind turbine blades and support structures...

P-scan 4 automatic UT system with integral scan contollers.
Large area precison scanners.
Absolutely ROCK SOLID software.
Unparalleled post-sales support.
(http://www.FORCE.dk)



    
 
 
Spartak Demchishin
Spartak Demchishin
06:28 Jun-09-2003
Re: looking for wind turbine blade testing method
We propose to use our impedance bond tester DAMI-C, in which tap test method is realized and there is a possibility of flaw image reconstruction using ultrasonic mapping technology(ultrasonic coordinates measuring system). Also we can elaborate special probes and scanner systems for these kind of applications.

Regards,
Head of transducers department
Spartak Demchishin
Votum JSC
www.votum.md

: Rotorblade ND-testing quality today is a question of inspectors level of educated guess. Conventional tap testing method is best today. Does anyone have better (objective) techniques? Are there experiences with electronic tap tester (woodpecker)?
: Thanks for wisdom.
.



    
 
 
Fred Perkins
Fred Perkins
00:58 Jun-11-2003
Re: looking for wind turbine blade testing method
Laser Shearography is a powerful and effective technique for improving on tap testing. Much faster, objective, and suitable for a wide range of materials, it may be well suited for your needs. You can find additional information at www.syncretek.com/automatic_shearography.htm.

Sincerely,
Fred Perkins
Syncretek LLC

: We propose to use our impedance bond tester DAMI-C, in which tap test method is realized and there is a possibility of flaw image reconstruction using ultrasonic mapping technology(ultrasonic coordinates measuring system). Also we can elaborate special probes and scanner systems for these kind of applications.
.
: Regards,
: Head of transducers department
: Spartak Demchishin
: Votum JSC
: www.votum.md
.
: : Rotorblade ND-testing quality today is a question of inspectors level of educated guess. Conventional tap testing method is best today. Does anyone have better (objective) techniques? Are there experiences with electronic tap tester (woodpecker)?
: : Thanks for wisdom.
: .
.



    
 
 
Randy Plis
Sales, Consultant
AMDATA NDE Technology LLC, USA, Joined Oct 1999, 23

Randy Plis

Sales, Consultant
AMDATA NDE Technology LLC,
USA,
Joined Oct 1999
23
09:15 Jun-16-2003
Re: looking for wind turbine blade testing method
Another possibility that may work is to perform a contact UT C-Scan, and analyze the acquired data using a "Power C-Scan". Such a test has worked well with other composite layups.

An example of another part inspection that is 100% tap tested, and statistically sampled (i.e., 10%) using the Power C-Scan can be downloaded from the following site: http://www.mtc62.com/lit.asp This application is a metal skin to honeycomb core, but the same inspection technology may also apply to your needs.

Lastly, this same system is offered with a phased array C-Scan capability. The use of phased array was suggested by a previous reply.

Best regards,
Randy Plis
AMDATA NDE Technology
www.amdatande.com


: Laser Shearography is a powerful and effective technique for improving on tap testing. Much faster, objective, and suitable for a wide range of materials, it may be well suited for your needs. You can find additional information at www.syncretek.com/automatic_shearography.htm.
.
: Sincerely,
: Fred Perkins
: Syncretek LLC
.
: : We propose to use our impedance bond tester DAMI-C, in which tap test method is realized and there is a possibility of flaw image reconstruction using ultrasonic mapping technology(ultrasonic coordinates measuring system). Also we can elaborate special probes and scanner systems for these kind of applications.
: .
: : Regards,
: : Head of transducers department
: : Spartak Demchishin
: : Votum JSC
: : www.votum.md
: .
: : : Rotorblade ND-testing quality today is a question of inspectors level of educated guess. Conventional tap testing method is best today. Does anyone have better (objective) techniques? Are there experiences with electronic tap tester (woodpecker)?
: : : Thanks for wisdom.
: : .
: .
.



    
 
 
Brian Larson
Brian Larson
00:05 Jun-21-2003
Re: looking for wind turbine blade testing method
The Computer-Aided Tap Tester (CATT) takes the subjectiveness out of tap testing. This relatively new device measures the contact time of an instrumented tap probe. The contact time changes with skin stiffness. The data can be collected by either hand tapping or by pushing an automated tapper unit that's about the size of a computer mouse across the surface. The data is fed into a computer and a C-scan image of the surface stiffness is produce. More information on the CATT system can be found at www.asi-nde.com


    
 
 
Per Nielsen
Per Nielsen
01:31 Jul-04-2003
Re: looking for wind turbine blade testing method
FORCE Technology (DK)have more than 10 years experience in performing large scale automated ultrasonic inspections on rotor blades,so technique and equipment is already available

: Rotorblade ND-testing quality today is a question of inspectors level of educated guess. Conventional tap testing method is best today. Does anyone have better (objective) techniques? Are there experiences with electronic tap tester (woodpecker)?
: Thanks for wisdom.
.



    
 
 
jagatheeswaran.s.
jagatheeswaran.s.
07:20 Jul-20-2003
Re: In Service inspections of wind turbine blade
i would like to know the type and the length of the blade along with the process the blades were manufactured as i am in the industry for the past 8 yrs.
fine pl.do contact for further details.
jaga.s.


Just a general comment on the actual needs for NDE of wind turbine blades. We have recently been in contact with a Scandinavian wind turbine manufacturer and frankly they don't really seem to worry about the integrity of the blades. Their concerns were about the long term performances of the metallic parts (gear box, shaft, etc..). According to them, the blades are overdimensioned since the weight issue is not as critical as in aerospace applications. Moreover there is right now very little legislation about safety since the mills are often located away from urban areas.
: Maybe,as Wolfang pointed out, offshore applications will be more critical (with environmental ageing issues and difficult maintenance) but it seems that the only ones interested in wind mill blade inspection are the NDE folks not the manufacturers or companies running the wind mills.
: It would be interesting to get reactions from "inside" the wind mill industry.
.
: Christophe Mattei
.



    
 
 
PRABHU SHANKAR
PRABHU SHANKAR
08:35 Aug-30-2004
Re: Information about the type and size of blades in windmills
hello sir
i am ME Student persuing my ENERGY ENGINEERING course in PSG college of technology , i need the details regarding my academic project on FAILURE ANALYSIS OF WIND TURBINE ROTOR BLADES.so please kindly send the details with this regard.
yours sincerely
PRABHU SHANKAR.


    
 
 
Thomas Niederreiter
Thomas Niederreiter
02:39 Apr-13-2005
Re: looking for wind turbine blade testing method
Hi Wolfgang,
I´m from a german company called Themosensorik GmbH. We are developer and producer of a test system for Wind-turbine blades with IR-FPA Array Cameras..-As well we´re producing the cameras ourselves. Theres not a already established System in Industry with our technique, but the principle we already established in finding defects (aerfoils,delmaniations)in turbine blades. The advantage of our system is, that it is fast (comparing to other methods like ultrasonic and others...), it has a picture as result (for documentation). So if you are interessted in such a system visit our hompage www.thermosensorik.de and write a email to info@thermosensorik.de (please write my Name in your question Mail)


    
 
 

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