Application of Smart Materials and Smart Structures to the Study of Aquatic Animals

Smart materials sense aspects of the environment and respond appropriately. Th ey also reverse that response when conditions change. For example, ferroelectric-based piezoelectrics generate electric polarity when subjected to mechanical stress. Conversely, if one applies a voltage to piezoelectric crystals, the crystals respond by changing shape in a linear direction. Electrostrictive and magnetostrictive are also smart materials. Th ese materials change size in response to electric or magnetic stimuli, respectively, and produce a voltage when stretched. Rheological smart

materials are fl uids that change state instantly in response to electrical (electrorheological) or magnetic (magentorheological) stimuli. Electrochromic materials have the ability to change their optical properties when an electric current is applied. And smart gels shrink or swell by factors of 1000 or more a factor useful to absorb or release fl uids. Similarly, smart fabrics are fabrics with a special coating that causes them to contract when strain surpasses a specifi ed limit.