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Technical Discussions
Jeffery
R & D, Ultrasonic Phased Array, Physical Science, NAS-410 LIII
NASA, USA, Joined Dec 1999, 37

Jeffery

R & D, Ultrasonic Phased Array, Physical Science, NAS-410 LIII
NASA,
USA,
Joined Dec 1999
37
01:01 Dec-14-1999
Laser Ultrasonics

I am interested in getting some feedback from anyone who has experience with Laser UT. We here in the NDE facility at NASA's MSFC, are interested in upgrading our Ultrasonic capabilities.

As each year goes by, we are getting larger, and more complex geometry structures, that need to be inspected. Laser UT *seems* to be a good investment, but I'd like to get a feel as to how other people's experience with it is.

We typically do inspections in large automated immersion systems, but we'd like to go to the field, with a little more speed, than a typical contact Ultrasonic unit will afford us.

Thanks to anyone with information -

Jeffery


    
 
 Reply 
 
J. Mark Davis
Teacher, And Consultant
University of Ultrasonics, Birmingham, Alabama, USA, Joined Mar 2000, 85

J. Mark Davis

Teacher, And Consultant
University of Ultrasonics, Birmingham, Alabama,
USA,
Joined Mar 2000
85
02:55 Dec-19-1999
Re: Laser Ultrasonics
: I am interested in getting some feedback from anyone who has experience with Laser UT. We here in the NDE facility at NASA's MSFC, are interested in upgrading our Ultrasonic capabilities.

: As each year goes by, we are getting larger, and more complex geometry structures, that need to be inspected. Laser UT *seems* to be a good investment, but I'd like to get a feel as to how other people's experience with it is.

: We typically do inspections in large automated immersion systems, but we'd like to go to the field, with a little more speed, than a typical contact Ultrasonic unit will afford us.

: Thanks to anyone with information -

: Jeffery

Jeffrey,

Have you contacted the people at Idaho National Labs. They have done a lot of research on Laser UT using EMATS. It looks like you are with Marshall. I am in Birmingham.

Try contacting Mike Anderson at INEL at (208)526-8780.

Also, you might contact Gary Workman at UAH.

Are you aware that the Spring 2000 ASNT Conference is in Birmingham??

J.Mark Davis




    
 
 Reply 
 
Rolf Diederichs
Director,
NDT.net, Germany, Joined Nov 1998, 608

Rolf Diederichs

Director,
NDT.net,
Germany,
Joined Nov 1998
608
02:10 Dec-19-1999
Re: Laser Ultrasonics
: I am interested in getting some feedback from anyone who has experience with Laser UT. We here in the NDE facility at NASA's MSFC, are interested in upgrading our Ultrasonic capabilities.

: As each year goes by, we are getting larger, and more complex geometry structures, that need to be inspected. Laser UT *seems* to be a good investment, but I'd like to get a feel as to how other people's experience with it is.

: We typically do inspections in large automated immersion systems, but we'd like to go to the field, with a little more speed, than a typical contact Ultrasonic unit will afford us.

: Thanks to anyone with information -

: Jeffery
--------------------------

So far no technical discussion started on Jeffery's topic of Laser Ultrasonics (Christmas coming soon!). At least I would like to start with some basics.
Laser generated ultrasonics is particular suitable for inspecting of composite materials and for complex geometry applications and can detect corrosion in metallic airframes. Since this method needs no contact medium and the source can be some meters away; it is used especially for applications such as NDT for very hot materials. However, optical detection is much less sensitive than the piezoelectric method, thus the signal-to-noise ratio of about 40 dB is achieved.
Laser can produce broadband ultrasound up to frequencies of about 100 MHz. Picosecond-pulse lasers can produce much higher frequencies. In many materials the higher frequencies will be attenuated, but for thin film measurements, the short ultrasonic pulses are very useful. Film thicknesses on the order of microns can be measured with these pulses.
With regard to cost, it is clear that laser systems are more expensive than transducer systems, but this
comparison is academic, because laser systems are only interesting for applications where transducers can
not be used.

C. Fiedler, Wright Laboratory, presented
Laser Based Ultrasound - Advantages/Disadvantages

Advantages:
Laser Based Ultrasound(LBU) inspections require minimum setup time.
LBU inspections do not require special fixtures
LBU works well on curved parts
LBU works in production invironment
Does not contaminates parts - can be used in-process
Requires only single sided access
LBU is cost effective in niche markets

Disadvantages:
High Initial cost
Less Sensitivity
Inspection varies with material/coating
Cannot penetrate honeycomb stiffened materials
No through transmission

References:
http://www.ndt.net/article/ecndt98/aero/002/002.htm
Laser-Ultrasonics Inspection and Characterization of Aeronautic Materials

http://www.ndt.net/abstract/asntf97/064.htm
Air Force Large Area Composite Inspection Systems

http://www.ndt.net/abstract/asntf97/065.htm
Results of Laser Ultrasonic Inspection of Aerospace Components

UT-Encyclopedia: Laser generated ultrasound
http://www.ndt.net/article/az/ut/info/laser.htm


    
 
 Reply 
 
Jeffery
R & D, Ultrasonic Phased Array, Physical Science, NAS-410 LIII
NASA, USA, Joined Dec 1999, 37

Jeffery

R & D, Ultrasonic Phased Array, Physical Science, NAS-410 LIII
NASA,
USA,
Joined Dec 1999
37
00:14 Dec-20-1999
Re: Laser Ultrasonics
Rolf -

Thanks for that information. I am interested more in, volumetric inspection of thicknesses of about .250" or less, but not really interested in thickness coatings, or very thin materials.

I will take a look at the links - so far, it seems many use Laser UT for very thin materials ... our application would be 18 - 24 ply composite, tape lay-up, materials.

Thanks again -

Jeffery

: So far no technical discussion started on Jeffery's topic of Laser Ultrasonics (Christmas coming soon!). At least I would like to start with some basics.

: Advantages:
: Laser Based Ultrasound (LBU) inspections require minimum setup time.
: LBU inspections do not require special fixtures
: LBU works well on curved parts
: LBU works in production invironment
: Does not contaminates parts - can be used in-process
: Requires only single sided access
: LBU is cost effective in niche markets

: Disadvantages:
: High Initial cost
: Less Sensitivity
: Inspection varies with material/coating
: Cannot penetrate honeycomb stiffened materials
: No through transmission




    
 
 Reply 
 
Jeffery
R & D, Ultrasonic Phased Array, Physical Science, NAS-410 LIII
NASA, USA, Joined Dec 1999, 37

Jeffery

R & D, Ultrasonic Phased Array, Physical Science, NAS-410 LIII
NASA,
USA,
Joined Dec 1999
37
00:20 Dec-20-1999
Re: Laser Ultrasonics
J.M. Davis -

Nice to hear from you ... I do work in Huntsville, at Marshall. If you ever make it up this way, look me up - I'll show you what we have here.

We have some experience in EMAT systems ... working with NASA's Michould facility in New Orleans. Ah yes ... Gary Workman - he is a regular face in my building here at MSFC. Actually, I haven't seen him in a while now. Next time I see him, I'll ask him about it too.

Thanks for the contact information ... I'll be looking into it.

Jeffery


: Jeffrey,

: Have you contacted the people at Idaho National Labs. They have done a lot of research on Laser UT using EMATS. It looks like you are with Marshall. I am in Birmingham.

: Try contacting Mike Anderson at INEL at (208)526-8780.

: Also, you might contact Gary Workman at UAH.

: Are you aware that the Spring 2000 ASNT Conference is in Birmingham??

: J.Mark Davis




    
 
 Reply 
 
Rolf Diederichs
Director,
NDT.net, Germany, Joined Nov 1998, 608

Rolf Diederichs

Director,
NDT.net,
Germany,
Joined Nov 1998
608
01:01 Jan-06-2000
Re: Laser Ultrasonics
In the recent Table of Contents Delivery Service I noticed the following articles:

JT Aviation week and space technology.
DA NOV 29 1999 v 151 n 22
PG 44
TI Laser ultrasonic tool images composite parts.
SU Such as large fuel tanks and assemblies for F-22, Joint Strike Fighter.

JT Experimental mechanics.
DA DEC 01 1999 v 39 n 4
PG 329
AU Lanza di Scalea, F.
AU Green Jr., R.E.
TI High-sensitivity Laser-based Ultrasonic C-scan System for Materials Inspection.


Table of Contents Delivery Service - Ultrasonic Testing
http://www.ndt.net/publicat/bibliog/toc_0100.htm

-----------------
: I am interested in getting some feedback from anyone who has experience with Laser UT. We here in the NDE facility at NASA's MSFC, are interested in upgrading our Ultrasonic capabilities.

: As each year goes by, we are getting larger, and more complex geometry structures, that need to be inspected. Laser UT *seems* to be a good investment, but I'd like to get a feelas to how other people's experience with it is.

: We typically do inspections in large automated immersion systems, but we'd like to go to the field, with a little more speed, than a typical contact Ultrasonic unit will afford us.

: Thanks to anyone with information -

: Jeffery




    
 
 Reply 
 
Emmanuel Lafond
Emmanuel Lafond
01:28 Jan-14-2000
Re: Laser Ultrasonics
Hello Jeffery,

As indicated by Richard Roberts, Lasson Technologies
is a good address. I know Marvin Klein, Bruno Pouet
and Dave Bacher and they have a lot of experience in
laser UT. (http://www.lasson.com)
I don't know Mike
Anderson from INEEL mentionned by J. Mark Davis, but
you may want to contact Kenneth Telschow there
(Phone: 208 526-1264, Fax: 208 526-0690,
telsch@inel.gov) who has really a lot of experience
in Laser UT.
The bible is for us "Laser Ultrasonics:
Techniques and Applications", Adams Hilger editor,
New York, 1990, from C.B Scruby & L.E. Drain. It's
aging a little bit but still a good book on the
fundamental aspects of laser ultrasonics.
I have a copy of the report on the workshop on
"Industrial Applications of Laser
Ultrasonics" organized by the U.S. Dept. of Energy in
December 97 at Johns Hopkins University, Baltimore, MD
that I can send you if you're interested.
If you want to use a Fabry-Perot for detection, the
wizard in this domain is Jean-Pierre Monchalin, from
Industrial Materials Institute, in Boucherville, Canada
(http://www.imi.nrc.ca/tofcpi.html). I used to perform
NDT using laser ultrasonics on aerospace parts for
Aerospatiale, that's why I happen to know all these
people. Hope this helps,

Emmanuel Lafond


    
 
 Reply 
 
Marc Choquet
Marc Choquet
08:17 Feb-19-2001
Re: Laser Ultrasonics
Since you are from NASA, I would suggest contacting Eric Madaras @ e.i.madaras@larc.nasa.gov who have been working in laser-ultrasonics for at least the past 5 years.
As for the equipment, the type of laser ultrasonic detection system you should consider will depend on the type of inspection you want to make. If the part is stationary and scanned slowly, you should look at a photorefractive based deteciton unit (such as our TWM series). These system have a very good low frequency response (cut-off frequency can be under 10kHz) with very good sensitivity. This is particularly interesting for porosity evaluation.
If you want a rapid scanning system, then you would have to go with a Fabry-Perot based system (such as our FPC series). However, you would then have to limit the low frequency cut-off to around 1 to 2 MHz.
On the generation side, you should look at CO2 laser system. These lasers have shown in the past to be very good in generating strong ultrasonic longitudinal wave with no damage to graphite-epoxy composite.
If you need more information, please feel free to contact me.
Marc Choquet.


    
 
 Reply 
 
hossein
hossein
09:26 Oct-09-2001
Re: Laser Ultrasonics
: J.M. Davis -

: Nice to hear from you ... I do work in Huntsville, at Marshall. If you ever make it up this way, look me up - I'll show you what we have here.

: We have some experience in EMAT systems ... working with NASA's Michould facility in New Orleans. Ah yes ... Gary Workman - he is a regular face in my building here at MSFC. Actually, I haven't seen him in a while now. Next time I see him, I'll ask him about it too.

: Thanks for the contact information ... I'll be looking into it.

: Jeffery


:
: : Jeffrey,

: : Have you contacted the people at Idaho National Labs. They have done a lot of research on Laser UT using EMATS. It looks like you are with Marshall. I am in Birmingham.

: : Try contacting Mike Anderson at INEL at (208)526-8780.

: : Also, you might contact Gary Workman at UAH.

: : Are you aware that the Spring 2000 ASNT Conference is in Birmingham??

: : J.Mark Davis
: : hossein bahrami



    
 
 Reply 
 
mehdi shafiei
mehdi shafiei
08:26 Nov-24-2001
Re: Laser Ultrasonics
: I am interested in getting some feedback from anyone who has experience with Laser UT. We here in the NDE facility at polytechnic university of iran, are interested in upgrading our Ultrasonic capabilities.

: As each year goes by, we are getting larger, and more complex geometry structures, that need to be inspected. Laser UT *seems* to be a good investment, but I'd like to get a feel as to how other people's experience with it is.

: We typically do inspections in large automated immersion systems, but we'd like to go to the field, with a little more speed, than a typical contact Ultrasonic unit will afford us.

: Thanks to anyone with information -

: mehdi shafiei



    
 
 Reply 
 
Tim
Tim
02:00 Dec-09-2006
Gatoradee New
Has Anyone seen the new Gatoradee ad? It's Hilarious!


    
 
 Reply 
 

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