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 Serendipity uncovers borophene's potential
23.02.2017 | Northwestern University

nachricht Switched-on DNA
20.02.2017 | Arizona State University

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Stingless bees have their nests protected by soldiers

24.02.2017 | Life Sciences

New risk factors for anxiety disorders

24.02.2017 | Life Sciences

MWC 2017: 5G Capital Berlin

24.02.2017 | Trade Fair News

VideoLinks
B2B-VideoLinks
More VideoLinks >>>