Featured Research

from universities, journals, and other organizations

Space Research Provides Earthshaking Revelations

Date:
October 6, 1997
Source:
National Aeronautics And Space Administration
Summary:
Research aboard the Space Shuttle is helping to provide a way to protect structures from major vibrations such as those produced by severe earthquakes and high winds.

Research aboard the Space Shuttle is helping to provide away to protect structures from major vibrations such as those producedby severe earthquakes and high winds.

Dr. Mark S. Whorton, an aerospace engineer at NASA's Marshall SpaceFlight Center, Huntsville, AL, has been working for several years onresolving vibration problems in a microgravity environment that can affectsensitive science experiments conducted aboard the Shuttle in orbit.

"Movements of the Shuttle, such as attitude corrections and theactivities of the crew members aboard the vehicle, create vibrations thatcan affect delicate experiments being conducted on board," he said."Solutions to reducing these minor vibrations in space also can be appliedto reducing the effect of major vibrations produced by earthquakes and high winds on terrestrial structures such as buildings and bridges."

Whorton has been conducting his research as part of his doctoralstudies program under Dr. Anthony J. Calise in the School of AerospaceEngineering at the Georgia Institute of Technology in Atlanta. The researchis part of a larger National Science Foundation effort to understand dynamicloads placed on structures by earthquakes and to identify ways of reducingtheir effect. The Georgia Tech research team for the past eight years hasbeen studying the benefits of using passive and active control strategies to reduce the effects of earthquakes on buildings.

"Technologies we've developed here at Marshall to protect experimentssuch as those involving crystal growth aboard the Space Shuttle are directlyapplicable to buildings and bridges during seismic events. Right now we'reworking on developing technological 'tools' which architects and constructionengineers can use when designing more earthquake-tolerant structures and inenabling existing structures to better survive earthquakes," Whorton said.

The National Science Foundation, under its program on EarthquakeHazards Mitigation in the Civil and Mechanical Systems Division, is funding amajor research program on structural control. Under this effort, the GeorgiaInstitute of Technology and other universities are involved in various aspectsof earthquake engineering such as developing better building materials, passivedamping methods, and active vibration control. Research activities at Marshallare focused in the area of active vibration control.

There are several ways to reduce the effect of structural vibrations.A direct approach is to stiffen the structure, which requires changing its massand therefore its vibration characteristics. While this may be acceptable formany terrestrial applications, the need for strong but lightweight structuresin space renders this option infeasible for NASA.

"Clearly, for applications in the space program, lightweight butequally effective vibration-mitigating alternatives were needed. We foundthat these technologies had down-to-Earth applications as well. One way ofcountering structural vibrations caused by a strong gust of wind or seismicground motion is to place sensors and force producing devices called actuatorsat specific locations on buildings. As sensors in the system measure themotion of the structure, actuators apply forces to counteract the structure'svibrations," Whorton said.

"One such force device would use hydraulic pistons moving counter-weights. Another method involves placing adjustable tendons along the sidesof structures. In fractions of a second, sensors in the systems can read thestructural vibration patterns caused by earthquakes or high winds and adjustthe tension on the appropriate tendons to reduce the excessive forces ormotions of the building," Whorton said.

All the actively controlled buildings in operation today are in Japanwith the exception of one in Taiwan. A TV tower in Nanjing, China, also is tobe retrofitted with active vibration control. Other new construction willincorporate the technology, particularly in seismically active regions; and itmay be possible to retrofit the technology to other existing structures.

"This technology -- in part derived from the nation's space program --is being adapted to meet the needs of the construction industry around theglobe," Whorton said. "The active control technology for vibration isolationis mature and is fully capable of doing the job. This is a technology readynow for commercial applications."


Story Source:

The above story is based on materials provided by National Aeronautics And Space Administration. Note: Materials may be edited for content and length.


Cite This Page:

National Aeronautics And Space Administration. "Space Research Provides Earthshaking Revelations." ScienceDaily. ScienceDaily, 6 October 1997. <www.sciencedaily.com/releases/1997/10/971006051031.htm>.
National Aeronautics And Space Administration. (1997, October 6). Space Research Provides Earthshaking Revelations. ScienceDaily. Retrieved September 18, 2014 from www.sciencedaily.com/releases/1997/10/971006051031.htm
National Aeronautics And Space Administration. "Space Research Provides Earthshaking Revelations." ScienceDaily. www.sciencedaily.com/releases/1997/10/971006051031.htm (accessed September 18, 2014).

Share This



More Earth & Climate News

Thursday, September 18, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Raw: Wildfires in CA Burn Forest Asunder

Raw: Wildfires in CA Burn Forest Asunder

AP (Sep. 18, 2014) An out-of-control Northern California wildfire has nearly 2,800 people from their homes as it continues to grow, authorities said Thursday. Authorities said a man has been arrested on suspicion of arson for starting the fire on Saturday. (Sept. 18) Video provided by AP
Powered by NewsLook.com
Raw: Elephant Undergoes Surgery in Tbilisi Zoo

Raw: Elephant Undergoes Surgery in Tbilisi Zoo

AP (Sep. 18, 2014) Grand the elephant has successfully undergone surgery to remove a portion of infected tusk at Tbilisi Zoo in Georgia. British veterinary surgeons used an electric drill to extract the infected piece. (Sept. 18) Video provided by AP
Powered by NewsLook.com
Raw: Scientists Examine Colossal Squid

Raw: Scientists Examine Colossal Squid

AP (Sep. 16, 2014) Squid experts in New Zealand thawed and examined an unusual catch on Tuesday: a colossal squid. It was captured in Antarctica's remote Ross Sea in December last year and has been frozen for eight months. (Sept. 16) Video provided by AP
Powered by NewsLook.com
Man Floats for 31 Hours in Gulf Waters

Man Floats for 31 Hours in Gulf Waters

AP (Sep. 16, 2014) A Texas man is lucky to be alive after he and three others floated for more than a day in the Gulf of Mexico when their boat sank during a fishing trip. (Sept. 16) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins