(Press-News.org) Only when you are standing beside a wind turbine can you appreciate the immense size of the wind turbine and its rotor blades. The largest wind turbines operating in the world today have rotor blades over 60 meters long – roughly equivalent to three truck-and-trailer units end-to-end. Within the next ten years, manufacturers of high-output wind turbines for offshore wind farms plan to produce blades up to 90 meters long. The prototypes of these new blades have to be tested and certified before they can go into production, and that requires equally as large testing facilities.
The Fraunhofer Institute for Wind Energy and Energy System Technology (IWES) in Bremerhaven is preparing for these outsized rotor blades. In early summer IWES will be inaugurating a new facility with the capability of testing rotor blades up to 90 meters long. The central feature of the new test facility will be a tiltable 1000 metric tons steel and reinforced concrete mounting block. Hydraulic cylinders used to tilt the block and additional cylinders to load the blade will allow the IWES engineers to bend a rotor blade as easily as a finger to a blade of grass. Preparations for testing begin by firmly mounting the flange of the rotor blade to the tilt block while the tip of the rotor blade projects upwards at a slight angle. Loading cables are attached at various locations along the blade and to hydraulic cylinders mounted on the floor. When all the cables and hydraulic cylinders are in place, the loading and tilting are initiated. As the tilt block is rotated and the tip of the blade begins to move upward, the rotor blade bends as its upward movement is counteracted by the loading cables pulling downwards. This unique testing setup allows for the blade tip of 90 meter blades to be bent through a distance of 25 meters.
The IWES researchers and engineers will be building upon their prior rotor blade testing experience with the new 90 meter testing facility. A test facility for rotor blades up to 70 meters long was opened at IWES in Bremerhaven in 2009, but it is not equipped with a tiltable mounting block. "The big advantage of the hydraulic tiltable mounting block is that it allows us to set up the ideal configuration for conducting tests with high precision in a minimum amount of time," says Falko Bürkner, who leads the rotor-blade testing team at IWES. This is especially important when testing the blades under extreme conditions, which involves subjecting the blades to the maximum theoretical loading it has been designed to withstand, i.e. 100% of the design load. This is always an anxious moment for the manufacturer: are our calculations accurate, is the structure robust enough?
The new test facility is not solely devoted to extreme load testing, but is also outfitted to simulate the cyclic forces acting on the rotor blades as they rotate due to the force of the wind. The wind and in turn rotation of the turbine causes constantly changing forces to act on the carbon or glass fiber reinforced materials of the rotor blades. "There is no other engineered rotating system in which the materials must support so many changes in the load parameters," says Bürkner. This fatigue loading is simulated in the new facility by a hydraulic cylinder which alternately pushes and pulls on the blade, causing it to vibrate at its horizontal and/or vertical resonant frequencies. A full series of extreme load and endurance tests takes around four months to complete. During this time, the blade is subjected to the same loads that it would normally have to withstand in 20 years of operation. Bürkner is confident that the new facilities will enable the institute to continue its mission well into the future. "We have a full schedule for the next twelve months – and that is even before the new test hall opens on June 9, 2011." IWES experts will be present at the Hannover Messe on April 4-8, 2011 (Hall 27, Stand H 24) to present a 3-D film of their biaxial rotor-blade testing and provide information for other new testing options. An open day for members of the public will be held at the new rotor-blade test center on June 11, 2011.
INFORMATION:
Extreme testing for rotor blades
2011-04-29
[Attachments] See images for this press release:
ELSE PRESS RELEASES FROM THIS DATE:
Taking safety personally
2011-04-29
A year after the BP explosion and oil spill, those trying to find someone to blame are misguided, says psychological scientist E. Scott Geller, Alumni Distinguished professor at Virginia Tech, and author of a new paper published in Current Directions in Psychological Science, a journal of the Association for Psychological Science. Geller has spent much of his 42-year career developing interventions to keep people safe, particularly helping companies develop a culture that promotes occupational safety.
There's almost never one person to blame for an injury; instead, companies ...
Inverting a standard experiment sometimes produces different results
2011-04-29
Nanoparticles will soon be used as tiny shuttles to deliver genes to cells and drugs to tumors in a more targeted way than was possible in the past.
But as the scientists prepare to use the nanoparticles in medicine, concerns have arisen about their potential toxicity.
Studies of both the applications of nanoparticles and their toxicity rely on the ability of scientists to quantify the interaction between the nanoparticles and cells, particularly the uptake (ingestion) of nanoparticles by cells.
In the standard laboratory tests of the biological activity of nanoparticles, ...
Fish livers contain beneficial fatty acids
2011-04-29
The fishing industry usually discards fish livers, but a team of researchers from the University of Almeria (Spain) has confirmed that they are a good source of polyunsaturated fatty acids, which are beneficial to health. Anchovies are one of the fish whose livers contain the highest levels of these substances.
Fish livers have hardly been used to date, with exceptions such as cod livers, which are used to produce the well-known medicinal oil. In general, fishermen tend to throw fish entrails away into the sea, and if they make it to processing plants they are one of ...
Dr. Michael Collins publishes paper on ivory-billed woodpecker
2011-04-29
Dr. Michael Collins, Naval Research Laboratory scientist and bird watcher, has published an article titled "Putative audio recordings of the Ivory-billed Woodpecker (Campephilus principalis)" which appears in the March issue of the Journal of the Acoustical Society of America. The audio recordings were captured in two videos of birds with characteristics consistent with the Ivory-billed Woodpecker. This footage was obtained near the Pearl River in Louisiana, where there is a history of unconfirmed reports of this species. During five years of fieldwork, Collins had ten ...
New insight into chromosome segregation: Centromere-independent kinetochore assembly
2011-04-29
One of the most critical tasks that a dividing cell must accomplish is the successful delivery of a complete set of genetic information to each new daughter cell. Now, a study published by Cell Press in the April 29th issue of the journal Cell, provides fascinating new insight into the complex of proteins that orchestrates the proper segregation of human chromosomes during cell division.
During the process of mitosis, DNA and its associated packing proteins are arranged into structures called chromosomes that are duplicated and then segregated. Duplicated chromosomes ...
Nanotechnologists must take lessons from nature
2011-04-29
It's common knowledge that the perfect is the enemy of the good, but in the nanoscale world, perfection can act as the enemy of the best.
In the workaday world, engineers and scientists go to great lengths to make the devices we use as perfect as possible. When we flip on a light switch or turn the key on the car, we expect the lights to come on and the engine to start every time, with only rare exceptions. They have done so by using a top-down design process combined with the application of large amounts of energy to increase reliability by suppressing natural variability.
However, ...
Era of canopy crane ending; certain research and education activities remain
2011-04-29
The 25-story construction crane used since 1995 to investigate such things as how Pacific Northwest forests absorb carbon dioxide, obtain sufficient water and resist attacks by pests and diseases is being pruned back to just the tower.
The Wind River Canopy Crane, located in a 500-year-old forest near Stevenson in southwest Washington, has been operated cooperatively by the University of Washington, the Forest Service's Pacific Northwest Research Station and the Gifford Pinchot National Forest. The partners say the jib – the arm of the crane – is being removed because ...
Pediatric flu vaccination: Understanding low acceptance rates could help increase coverage
2011-04-29
A study of H1N1 and seasonal influenza vaccination in a sample of black and Hispanic children in Atlanta found a low rate of vaccine acceptance among parents and caregivers. Only 36 percent of parents and caregivers indicated they would immunize children against H1N1, and 22 percent indicated their children received the seasonal influenza vaccine in the previous three months. The majority of children in the sample (71 percent) were from households with less than $40,000 in annual income.
Researchers say this low level of vaccine coverage and acceptance highlights the ...
As the worm turns, its secrets are revealed
2011-04-29
An international team of scientists, led by researchers at the University of California, San Diego School of Medicine, have developed a new method for discerning the functions of previously uncharacterized genes and placing them in interactive, functional networks that reveal how gene products interact to bring about cellular events.
The research is published in the April 29 issue of the journal Cell. It was led by principal investigators Karen Oegema, PhD, professor of cellular and molecular medicine and head of the Laboratory of Mitotic Mechanisms in the Ludwig Institute ...
From the beginning, the brain knows the difference between night and day
2011-04-29
The brain is apparently programmed from birth to develop the ability to determine sunrise and sunset, new research on circadian rhythms at the University of Chicago shows.
The research sheds new light on brain plasticity and may explain some basic human behaviors, according to Brian Prendergast, associate professor in psychology at the University of Chicago and co-author of a paper published April 27 in the journal PLoS One. The lead author is August Kampf-Lassin, an advanced graduate student at the University.
"This finding may show us why infants of many species eventually ...