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SHAPE MEMORY ALLOYS The potential is almost as huge as the cost to capture it


With shape memory alloys (SMAs) being a relatively new field, few people can talk about their practical significance in the automotive sector, although some consultants have heard about them, including Erich Merkle, vice president of forecasting at automotive consultancy IRN Inc., Grand Rapids, Mich.

"The real benefit is weight savings, and anything that saves weight is important because fuel efficiency is becoming such a big issue and often times suppliers will say 'I can save weight here, but at what cost?' So if you can actually reduce cost and actually save weight, it shouldn't be a really tough sell to automakers if, in fact, that is true," Merkle said. "But it's still down the road. I don't know of it being in use anywhere. But if you can make a good value proposition in terms of weight savings and cost savings, it would make very good economic sense, especially if you can replace motors with this type of product."

There is always intense competition between materials, and manufacturers of the different materials have the ability to respond to market forces, Dennis DesRosiers, founder and president of DesRosiers Automotive Consultants Inc., Richmond Hill, Ontario, said. "Obviously, the growth of plastics has led to a significant response on a wide variety of fronts from metals. If you go back two decades, people were talking about the end of steel in vehicles as we knew them at the time, but steel content has continued to grow or at least hold its share. This (SMAs) is just another competitive response to a very competitive marketplace. Whether it works or doesn't work, I don't know, but nobody disappears."

Material choices are a complex "algorithm," with a wide variety of aspects to be considered in terms of selection, DesRosiers said, adding that the more the consumer wins the better it is for the automotive industry. "But in terms of how it's going to develop, I have no idea."

The primary barrier to widespread usage taking flight is the cost of entry research and development. It can add up to a significant amount when you factor in the time required for practical implementation of products using the materials, which in some cases are estimated at 20 years to reach the market.

But Giorgio Vergani, business development manager of SAES Getters SpA, Milan, Italy, sees a bright future for SMAs in today's automobile. He pointed to autos that feature an increasing number of sensors, actuators and microchips, which account for a major part of the weight and volume of vehicle components. "This is confirmed by the fact that despite research into new materials such as aluminum, plastics and composites, a new model usually weighs more than the previous model."

Today, more than 60 actuators on a vehicle are implemented exclusively with conventional electromagnetic motors, which in many cases aren't optimal in terms of weight, volume or reliability, Vergani said. "The use of 'smart materials' for actuation represents an excellent technological opportunity for the development of electromechanical components for the vehicle. Developers are particularly attracted by automotive applications due to the high sales volume involved. However, competition is very strong and the market is extremely price sensitive."

Researchers at the Polymorphic Robotics Laboratory at the University of Southern California (USC) are using shape-shifting technology to build modular robots capable of breaking themselves apart and re-forming into different shapes based on environment and terrain—forming a snake to squeeze into tight spaces, or a ball to roll downhill.

The SuperBot, as it's called, will have about 100 reconfigurable modules allowing it to crawl, walk, roll, climb, carry, fetch or survey. The individual modules basically dock and undock with each other—which is where SMAs come into play. An SMA system in the active end of the module controls a spring-loaded lock, allowing the robot modules to pull away from its neighbor at the joint. The reconfiguration and module exchanges don't require any special knowledge or training, with the key being a collective, cooperative operation. There's no central system controlling the modules, which negotiate movements collectively by signaling the other modules via miniature radio transmitters and receivers.

"Such robots are economic because a single robot can provide diverse behaviors and can be changed frequently. This is ideal for home companions, search and rescue, security, surveillance and so on," Polymorphic Robotics Laboratory says on its Web site.

"The SuperBot project will be built upon the first spiral of the development completed in the last decade with small-scale, Earth-oriented prototype self-reconfigurable robots by the proposing team, with total support of more than $8 million from DARPA (Defense Advanced Research Projects Agency), AFOSR (Air Force Office of Scientific Research), NSF (National Science Foundation) and NASA (National Aeronautics and Space Administration)," Wei-Min Shen, Polymorphic Robotics Laboratory's director, said in an abstract on the project.

Aircraft also stand to gain significantly from use of SMAs. The morphing project at NASA's Langley Research Center in Hampton, Va., has high hopes for SMAs and other "smart" alloys. The project aims to create an aircraft "capable of changing its features by reacting and adapting to diverse, multi-variable conditions in flight," according to information on NASA's Web site. It also could eventually lead to a space shuttle with self-healing skin to repair itself when hit by micrometeoroids in space.

"However, don't expect the technology to immediately materialize into some of the far-out conceptual aircraft capable of radically 'morphing' their shape," Anna McGowan, NASA's Morphing Aircraft project manager, said in a report published on the agency's Web site. "In fact, it will likely be in much smaller ways that the technology will first be seen."

Under the project, aircraft would take on more bird-like features, with sensors in the wings acting similarly to nerves in a bird's wing, essentially measuring wing surface pressures and issuing responses to changing flight conditions. The sensor responses would direct actuators functioning like muscles in a bird's wing. "And just as a bird instinctively uses different feathers on its wing to control flight, the actuators will change the shape of the aircraft's wings to continually optimize flying conditions," according to NASA. "Active flow control effectors will help mitigate adverse aircraft motions when turbulent air conditions are encountered, leading to more-efficient, better-performing and quieter aircraft."

Such aircraft are still a long way off, likely at least 20 years according to NASA estimates, but it's these fantastic, futuristic visionary concepts that keep researchers pushing onward and upward. "That's my job," McGowan said. "We are the Einsteins behind the theory of relativity. We are the Edisons behind the light bulb. When people say 'that can't be done,' I say 'thank you,' because that means we are looking at the right technologies."

Renate F. Mas, New York, contributed to this story.

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