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 -

Vallen-Systeme GmbH
The Acoustic Emission Company! Since 1987 Vallen stands for competence and continuity in AE and for reliable business cooperation and support.
349 views
Technical Discussions
Pedro
Spain, Joined Jan 2020, 1

Pedro

Spain,
Joined Jan 2020
1
20:02 Jan-07-2020
Detecting lack of bondings in metal/Nomex sandwiches

Hello and happy New Year everybody.
I currently have an application using sandwich panels made of aluminium skins (0.4 to 0.8mm thick) with Nomex honeycomb core (cell size of either 3.2mm or 4.8mm and thickness around 15mm). Adhesive films are employed to ensure the skin-to-core bonding.

As expected, ultrasonic through transmission is effective to detect the areas with lack of bondings (provided that the flaw has at least the area of 3 circumscribed cells in order for the wave to propagate in enough cell walls) but I cannot know if this defect is located at the lower skin-to-core interface or at the upper skin-to-core interface.

That's why I'm trying to identify an additional NDT method to inspect areas already known as flwaed from the UT inspection in order to know on which of the upper or lower interfaces it is located. Ideally, minium detectable size should be between 8 and 12mm. Tap test is not an option because not objective nor reliable enough for this application.

An Olympus BondMaster has been tried with Pitch-Catch and MIA probes and different kind of adjustments. Pitch-Catch seems to give some results, but sensitivity between safe and flawed areas is not big enough to ensure a reliable detection (either give false positive or miss some flaws) . It seems especially harder to get good sensitivity as the skin thickness under the probe increases.

Anyone already had to deal with similar application? Do you think I'm missing something and this should be possible with another resonance probe or equipment ? Another NDT technique easy to implement ?

Thank you very much in advance for your ideas, suggestions...

 
 Reply 
 
Carlos Caceres
,
Mexico, Joined Jan 2020, 1

Carlos Caceres

,
Mexico,
Joined Jan 2020
1
18:29 Jan-08-2020
Re: Detecting lack of bondings in metal/Nomex sandwiches
In Reply to Pedro at 20:02 Jan-07-2020 (Opening).

Hi Pedro

Have you try to try linear array pulse echo, I've inspect carbon fiber sandwich with aluminum core with different cell size. On some cases that ATTU flag an indication, the path forward is to perform Tap Test with hammer and Pitch-Catch Bondascope, Manual PE single element and if no luck, we perform Manual Phased Array PE, 5MHz 32el RotoArray from GE with U32 Max Testia UT box, and you can see were the cell walls adhesive fillets are not present.

Hope this advice helps you!

 
 Reply 
 
J.B.
J.B.
01:37 Jan-10-2020
Re: Detecting lack of bondings in metal/Nomex sandwiches
In Reply to Carlos Caceres at 18:29 Jan-08-2020 .

Your task is not a new task.
The solution is described in Airbus NDT procedures, which are well established since more than 10 years
Check e.g. Airbus A320 NTM 51-10-24 or using Array and Omniscan see Airbus A320 NTM 55-40-09.
This is an advanced universal procedure to check nearly every case of problem in honeycomb sandwich with ultrasound. Refer to the following Presentation from 2010:
https://www.ndt.net/article/atandt2010/papers/18.pdf

Check this forum posting: https://www.ndt.net/forum/thread.php?msgID=75311#75311
I described the task there already.

 
 Reply 
 
Simon Amallraja
Simon Amallraja
13:59 Jan-19-2020
Re: Detecting lack of bondings in metal/Nomex sandwiches
In Reply to Pedro at 20:02 Jan-07-2020 (Opening).

I can suggest couple of testing options- Advanced NDT Methods.
1. You can try Ultran Air Coupled UT System with their GMP (Gas Matrix Probes) for clear results. You can find about 5 mm x 5 mm size defects
2. Laser Shearography - you can use it for large components like up to 1800 mm x 1800 mm size in a single shot. You can choose different models suiting to your applications.
3. You can also use High Power and High UT Pulser Receivers from RITEC - a tone burst system like RPR 4000 with Air Coupled probes will give you better results.
4. All of these can be automated for different applications depends on need and component size.

if you need more info, you contact the manufacturers or email me. I will send required details

 
 Reply 
 

Product Spotlight

On-Demand Webinar: Advanced Ultrasonic Techniques for HTHA Detection & Assessment

In the Oil and Gas industry, High Temperature Hydrogen Attack (HTHA) can occur in steels operating a
...
t high temperature, usually above 205°C (400°F). Early stages of HTHA are very difficult to detect. Join us for a webinar presented by Guy Maes, Zetec Sales Engineer Director. The webinar will demonstrate how advanced ultrasonic techniques are deployed for efficient and reliable HTHA inspections.
>

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
>

FD800 Bench Top Flaw Detectors

The bench-top FD800 flaw detector range combines state-of-the-art flaw detection with advanced mater
...
ial thickness capabilities. Designed for use in the laboratory these gauges are the tool you need for all your flaw detecting needs.
>

GEKKO - Portable Phased Array Testing with TFM in Real-Time

The portable phased array testing system GEKKO provides 64 parallel test channels. On creating testi
...
ng parameters the operator is assisted by the CIVA software. Due to its modular set-up the GEKKO instrument is suitable for operators of all skill levels.
>

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