Profs. Christopher Niezrecki, above, Julie Chen and Peter Avitabile received a three-year $195,000 grant from the National Science Foundation to look at new methods for predicting dynamic stress and strain on vibrating flexible structures — such as wind turbine and helicopter blades — during operation using computer modeling and experimentation.
Profs. Christopher Niezrecki, above, Julie Chen and Peter Avitabile received a three-year $195,000 grant from the National Science Foundation to look at new methods for predicting dynamic stress and strain on vibrating flexible structures — such as wind turbine and helicopter blades — during operation using computer modeling and experimentation.
By Edwin L. Aguirre
As the United States and other countries deal with issues of climate change and global warming, one source of energy is looking more and more attractive: wind power.
“Wind power is a clean and sustainable alternative to fossil fuels,” says Mechanical Engineering Assoc. Prof. Christopher Niezrecki, a member of UMass Lowell’s Wind Energy Research Group (WERG). “It is plentiful, renewable, widely distributed and does not emit greenhouse gases during operation.”
Right now, coal is the most common fuel used for generating electricity in the United States. According to the U.S. Energy Information Administration, 45 percent of the country’s nearly 4 trillion kilowatt-hours of electricity produced in 2010 used coal. Wind power remains a small fraction of the U.S. total electricity production, at about 2 percent.
However, the U.S. Department of Energy (DOE) has set a national goal of reaching 20 percent wind-generated electricity by 2030, thereby reducing annual carbon dioxide emissions by up to 825 million metric tons. This is equivalent to taking 140 million cars off the road.
Niezrecki says land-based wind farms are already in operation in Texas, California, Iowa and Indiana, and similar facilities are planned offshore for Nantucket Sound. Wind already provides enough electricity for nearly 10 million homes in America, and much more wind power is on the way.
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One of the biggest challenges facing wind turbine makers and utility companies is the question of reliability of the turbine blades, either due to manufacturing defects or damage during operation.
“If the blades are not spinning, they are not generating electricity,” says Niezrecki. “This means loss of revenue for the companies and investors. Ultimately, such turbine downtimes raise the cost of generating electricity, making the wind farm prohibitively expensive to operate, especially when competing with fossil fuels.”
He says WERG is doing everything it can to make wind systems more reliable and less expensive to operate, giving consumers and corporations more incentive to adopt wind power as an economically viable source of energy.
Formed in late 2009, WERG consists of 13 interdisciplinary faculty members whose research focuses on turbine blade manufacturing, design and modeling, reliability, structural health monitoring and non-destructive inspection, energy storage and workforce and economic development. The group is supported by the DOE, the National Science Foundation, National Grid, the Massachusetts Technology Collaborative and the UMass President’s Office, and is collaborating with many industry partners and national laboratories.
“We are looking at new ways of detecting blade defects and/or damage by monitoring the vibration response of these blades during operation using optical sensing techniques, such as digital image correlation and photogrammetry with video cameras,” says Niezrecki. “This will help blade makers with quality control during manufacturing. It will also assist turbine operators in improving blade maintenance and avoiding costly repairs and replacements and help extend the life of the blade.”
He says turbine blades, which are made of fiberglass and other composite materials, can span up to nearly 300 feet in length.
“The challenge is that, as the blades get bigger and longer, the likelihood of having structural defects increases,” he says. “The blades’ lifetime is supposed to be 20 years; right now, they don’t last that long.”
To discuss the latest trends in wind energy research and its future, leaders and experts from academia, industry and government gathered at UMass Lowell for the Wind Energy Research Workshop in September. More than 150 people from across the country and Europe participated in the event hosted by WERG. In addition to plenary talks and panel sessions, the workshop featured a tour of the Wind Technology Testing Center’s brand-new facility in Charlestown.
“It is inevitable that the world would adopt wind power,” says Niezrecki. “It is also definitely possible for wind to surpass fossil fuels and nuclear energy in electricity production. But for that scenario to happen, it will require significant commitment on the part our government and overcoming a lot of political hurdles. If our country and our society is behind this goal 100 percent, it certainly can happen.”
www.uml.edu/research_labs/Wind_Energy_Research_Group/default.html
