Featured Research

from universities, journals, and other organizations

University Of Florida Engineers Probe "Shape Memory" Alloy For Better Prostheses

Date:
August 16, 2002
Source:
University Of Florida
Summary:
To keep blood vessels from clogging, surgeons sometimes implant compressed stents that expand to the right size and shape when warmed by body heat. The tiny stents get their so-called "shape memory" from an unusual alloy called nitinol, which exhibits one shape when cool, but forms another when heated. Intrigued by the alloy's biomedical potential, University of Florida researchers have recently begun investigating it for the much larger application of prosthetic limbs.

GAINESVILLE, Fla. --- To keep blood vessels from clogging, surgeons sometimes implant compressed stents that expand to the right size and shape when warmed by body heat.

The tiny stents get their so-called "shape memory" from an unusual alloy called nitinol, which exhibits one shape when cool, but forms another when heated. This property has made the alloy useful in an increasing number of small-scale medical and consumer products that depend on motion, yet do not have enough space for motors or pumps.

Intrigued by the alloy's biomedical potential, University of Florida researchers have recently begun investigating it for the much larger application of prosthetic limbs.

Under the direction of mechanical engineering Professor Carl Crane, UF master's student Jose Santiago-Anadon built a nitinol device that can move the equivalent of more than 100 pounds. While the apparatus is merely a weight-lifting machine now, the hope is the research will one day lead to a nitinol "muscle" that can mimic the strength and motion of the real thing – doing the work of a tendon or other major muscle in a next-generation prosthesis.

"Basically, it's almost the size of a tendon or other large muscle," Crane said. "It requires a lot of electricity, but it does not require the kind of bulky motors or hydraulic pumps that drive similar devices."

Nitinol was discovered by U.S. Navy researchers in the early 1960s. The name combines the abbreviations for nickel and titanium with the acronym for the Naval Ordnance Laboratory, where the first research on the alloy was done.

For years, nitinol was used only in niches. But the development of medical applications has spurred the creation of other nitinol commercial products, including showerheads that automatically shut off the flow of water before it becomes hot enough to scald a person.

The shape memory effect occurs in response to heat, which can be generated through electricity or any other energy source. Inducing the effect requires considerable energy, one reason the development has focused on small products with comparatively little nitinol, say Santiago-Anadon and Crane. Where energy is not a factor but space or weight is, however, large nitinol devices could be quite useful, they say.

To demonstrate that, Santiago-Anadon built a machine that uses 104 nitinol wires to displace the equivalent of 135 pounds – a weight measured by the wires' action against a metal block attached to mechanical and hydraulic springs. When Santiago-Anadon flips on the power switch, the thread-like wires constrict due to the heat generated by the electricity, lifting the block more than an inch. When he turns the power off, the hydraulic springs slowly return the wires to their original size.

When lifting the maximum weight, the machine requires some 1,200 watts, enough to power four computers. However, the wires are much lighter and potentially more compact than a hydraulic system or electric motor needed to do the same amount of work. That makes it a good candidate for prosthetic limbs, which would be hampered by such conventional machines. Santiago-Anadon predicted that researchers could develop a prototype arm prosthesis using shape memory alloys in about five years.

Prostheses, however, are not the only potential application for such large-scale nitinol devices. Nitinol already is used in outer space, for example in cylinders placed around bolts that elongate under temperature change, breaking the bolt to open a box and release a structure such as an antenna on a satellite. Because space is at such a premium in orbital vehicles, any other nitinol devices that replace motors or pumps could be useful, Santiago-Anadon said. The unobstructed heat from the sun in space, meanwhile, serves as an excellent energy source to cause the shape memory effect.


Story Source:

The above story is based on materials provided by University Of Florida. Note: Materials may be edited for content and length.


Cite This Page:

University Of Florida. "University Of Florida Engineers Probe "Shape Memory" Alloy For Better Prostheses." ScienceDaily. ScienceDaily, 16 August 2002. <www.sciencedaily.com/releases/2002/08/020816072745.htm>.
University Of Florida. (2002, August 16). University Of Florida Engineers Probe "Shape Memory" Alloy For Better Prostheses. ScienceDaily. Retrieved July 28, 2014 from www.sciencedaily.com/releases/2002/08/020816072745.htm
University Of Florida. "University Of Florida Engineers Probe "Shape Memory" Alloy For Better Prostheses." ScienceDaily. www.sciencedaily.com/releases/2002/08/020816072745.htm (accessed July 28, 2014).

Share This




More Matter & Energy News

Monday, July 28, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

The Carbon Trap: US Exports Global Warming

The Carbon Trap: US Exports Global Warming

AP (July 28, 2014) AP Investigation: As the Obama administration weans the country off dirty fuels, energy companies are ramping-up overseas coal exports at a heavy price. (July 28) Video provided by AP
Powered by NewsLook.com
Shipping Crates Get New 'lease' On Life

Shipping Crates Get New 'lease' On Life

Reuters - Business Video Online (July 25, 2014) Shipping containers have been piling up as America imports more than it exports. Some university students in Washington D.C. are set to get a first-hand lesson in recycling. Their housing is being built using refashioned shipping containers. Lily Jamali reports. Video provided by Reuters
Powered by NewsLook.com
Europe's Highest Train Turns 80 in French Pyrenees

Europe's Highest Train Turns 80 in French Pyrenees

AFP (July 25, 2014) Europe's highest train, the little train of Artouste in the French Pyrenees, celebrates its 80th birthday. Duration: 01:05 Video provided by AFP
Powered by NewsLook.com
TSA Administrator on Politics and Flight Bans

TSA Administrator on Politics and Flight Bans

AP (July 24, 2014) TSA administrator, John Pistole's took part in the Aspen Security Forum 2014, where he answered questions on lifting of the ban on flights into Israel's Tel Aviv airport and whether politics played a role in lifting the ban. (July 24) 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