Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Choosing a wave could accelerate airplane maintenance

24.07.2013
Ultrasonic waves can find bubbles and cracks in adhesive bonds holding airplane composite parts together, and now aerospace engineers can select the best frequencies to detect adhesive failures in hard-to-reach places more quickly, thanks to Penn State researchers.

Different ultrasonic modes work best for different materials and configurations using the right one will locate more flaws with higher precision, according to the researchers. The selection process could save time and effort for engineers who perform maintenance on complex structures made from composite materials -- like airplanes.


This image shows an experimental setup to test the ultrasonic wave modes selected by based on a variety of criteria. Researchers placed an ultrasonic wave emitter and receiver on either side of a sample bonded with adhesive to another surface. Faults purposely included are outlined in white.

Credit: Baiyang Ren

Adhesive bonds are better for attaching composite parts than nuts and bolts, which pierce and weaken structural integrity. But heavy operation can crack the glue, damaging the bond's effectiveness. Ultrasonic waves let engineers examine bonded regions without having to dismantle anything.

"This technique is very widely used in aerospace engineering because those structures require a very high reliability," said Baiyang Ren, postgraduate in engineering science and mechanics. "When something like an airplane or helicopter, bridge, ship has some component that fails suddenly, that could cause a severe accident."

For bonded regions located between easily accessible, wide surfaces, obtaining a clean readout is easy. Ultrasonic waves pass through the bonded intersection to a receiver on the other side without interference.

However, for bonds between inaccessible, irregularly angled surfaces, the ultrasonic wave will convert into a different mode by the time it enters and travels through the bonded region. This new wave mode may not be as sensitive to adhesive flaws.

"Usually…the mode conversion at this region is a blind thing for people," said Ren."We want to know (the mode conversion) so that we know how to inspect that bond."

There are thousands of ultrasonic modes, and for the best results, engineers have to choose one that will convert into the actual mode they want. Identifying the right one for a specific project through trial and error can be time-consuming.

Researchers devised a selection process to determine the best combination of ultrasonic modes for a given material by identifying the criteria for optimal frequencies and eliminating possibilities through a series of models and calculations.

"We want the mode to travel fast, travel longer, and be sensitive to this bond and still be received by some particular receiver," said Ren. "Each criteria will filter out some of the modes. After several steps, what things you have left are the modes that you want to try."

The results are available online in the International Journal of Adhesion and Adhesives.

To evaluate the efficacy of the selection process, researchers tested two of the optimal modes on pieces of carbon-fiber-reinforced polymer, glued together with planned defects created by inserting Teflon into the bonded region.

They then compared the results with a readout produced by one of the discarded frequencies. The two modes predicted to be successful detected flaws at a much finer resolution than the discarded one. Cliff Lissenden, professor of engineering science and mechanics, also worked on this project.

The U.S. Government funded this project.

A'ndrea Elyse Messer | EurekAlert!
Further information:
http://www.psu.edu

More articles from Materials Sciences:

nachricht Borophene shines alone as 2-D plasmonic material
21.11.2017 | Rice University

nachricht Quantum dots amplify light with electrical pumping
21.11.2017 | DOE/Los Alamos National Laboratory

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Nanoparticles help with malaria diagnosis – new rapid test in development

The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.

Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.

During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....

Im Focus: Researchers Develop Data Bus for Quantum Computer

The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.

Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

Previous evidence of water on mars now identified as grainflows

21.11.2017 | Physics and Astronomy

NASA's James Webb Space Telescope completes final cryogenic testing

21.11.2017 | Physics and Astronomy

New catalyst controls activation of a carbon-hydrogen bond

21.11.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>