This class of materials allows for the straightforward implementation of functions within load-bearing mechanical structures. While in artifacts such as machines or buildings, these functions are realized by adding actuators or sensors, smart structures provide these functions alongside mechanical load in a very simple and elegant manner. An example is an aerodynamic wing structure made of shape memory metal, which undergoes significant deformation with temperature changes. Instead of complex structural solutions to alter the aerodynamic shape, such as aerodynamic flaps, smart materials render these technical elements unnecessary.
Among the well-known smart materials are shape memory alloys, plastics, magnetostrictive metals, and piezoelectric materials. Piezoelectric materials have a crucial advantage: they can be shaped by changing an electric voltage and can be easily commanded by electronic control. Additionally, they are inherently very fast.
Smart materials have been extensively utilized in research projects and tested in technology demonstrators. Shape memory materials have been studied in programs aiming to realize aircraft wings that avoid the aerodynamic drawbacks of flaps, such as the opening of gaps in the wing during flap operation. In helicopter blades, piezoelectric materials have been investigated to enable rapid shape changes of the rotor blade during rotation. These fast-responding aerodynamic profiles facilitate the suppression of vibrations and noise. Due to their rapid response, piezoelectric materials are ideally suited for combating body sound vibrations in machinery or noise-reducing structures.
