Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Telltale heat

25.03.2009
At first glance, the rotor blade appears to be flawless, but the expert knows that outward appearances cannot be trusted. He taps the surface and listens.

A full, deep sound tells him that the laminate is homogeneous, while a more flat, hollow tone indicates irregularities in the material.


This is a thermographic image of air inclusions (light-colored) in a rotor blade. Credit: Fraunhofer WKI

Delaminated and hollow sections of a certain size near the surface can also be detected by running an expert hand over the surface material. But even an experienced inspector cannot find all hidden faults in this way.

Rotor blades consist mainly of glass fibers which are processed to form mats or meshes. In order to make a 60-meter rotor blade, hundreds of these mats have to be laid flat inside a mold and impregnated with special resins in a vacuum.

Even minor irregularities can cause air bubbles or other faults to form, and these often lead to mechanical stresses in the material when the blade is subjected to everyday loads. As a consequence, the laminate can rip and cause the rotor blades to fail prematurely.

Researchers at the Fraunhofer Wilhelm-Klauditz-Institut WKI in Braunschweig are able to make such faults visible. "Infrared thermography is well suited to this task, as it is fast, relatively cheap and doesn't cause any damage," explains WKI project manager Dr. Hiltrud Brocke. "The surface is briefly heated with an infrared radiator. A special camera shows how the heat front spreads inside the material. If the front hits on any air inclusions or delaminated areas, it accumulates because heat spreads less in air than in solid laminate."

In this way, the researchers can peer several centimeters into the material. "Because the equipment – the infrared radiator, a camera and a computer – is mobile, we can carry out measurements during production, at the end of the transport route, and also on fully assembled wind energy plants," says Brocke. The researchers will be demonstrating their technology on a rotor blade section incorporating several typical faults at the Hannover-Messe from April 20 to 24 (Hall 27, Stand G20).

Hiltrud Brocke | EurekAlert!
Further information:
http://www.wki.fraunhofer.de

More articles from Power and Electrical Engineering:

nachricht How protons move through a fuel cell
22.06.2017 | Empa - Eidgenössische Materialprüfungs- und Forschungsanstalt

nachricht Fraunhofer IZFP acquires lucrative EU project for increasing nuclear power plant safety
21.06.2017 | Fraunhofer-Institut für Zerstörungsfreie Prüfverfahren IZFP

All articles from Power and Electrical Engineering >>>

The most recent press releases about innovation >>>

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

Im Focus: Can we see monkeys from space? Emerging technologies to map biodiversity

An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.

Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

Individualized fiber components for the world market

23.06.2017 | Physics and Astronomy

How brains surrender to sleep

23.06.2017 | Life Sciences

Can we see monkeys from space? Emerging technologies to map biodiversity

23.06.2017 | Information Technology

VideoLinks
B2B-VideoLinks
More VideoLinks >>>