These materials could sense environmental disturbances such as earthquakes and change their properties to alleviate the effects of these events. SMAs are created by cyclic heating and cooling of an alloy using electric currents. SMAs may be metal alloys, such as nickel-titanium or ferrous alloys, ceramics or polymers. Steel alloys may have the greatest potential for structural uses at the lowest cost. Several challenges are associated with production of SMAs, including determination of material composition, difficulty of thermomechanical processing, fatigue life and, especially, cost and scale.
Much work remains to be done before SMAs can be used cost-effectively in new construction.
These structures, called actively controlled systems, were the first generation of smart structures. There are about 20 buildings in Japan that have these computer-controlled active seismic absorption devices. Japan is the only country where this technology has been implemented in structural systems. Furukawa and Masuka arrived at NC State to conduct research with Noori earlier this fall. They hope to apply their research advances to several aspects of earthquake mitigation technology, particularly structural health monitoring of existing structures.