Material Issues of Smart Structures

In 1997 BMBF, within the framework of an Adaptronics describes the field of technology in developing a new class of so-called intelligent structures. This concept starts out from the development of adaptive systems which, due to their self-regulating mechanisms, are able to self-adapt to different requirement conditions. This requires a system-optimized linking of sensors and actuators on the basis of new functional materials, such as piezoceramic fibers and patches with adaptive controllers. These new structural systems are then able to self-adjust to changing external conditions through selfoptimization, thus preventing the occurrence of disturbing deformations, etc. As a result, it will also become possible to suppress vibrations right at the place at which they occur and, consequently, preclude structure-borne noise problems which are often linked with vibrations. In contrast to classical approaches employing special spring systems, hydraulic-pneumatic dampers, damping materials, etc., adaptive components form an integral part of the structure. They fulfil both load-bearing and actuator/ sensor functions and, hence, are multifunctional. Therefore, adaptronics will become an essential prerequisite for further development of ultralight structures. On the one hand, this process requires new approaches by engineers as, apart from classical stiffness and strength considerations, they also need to include in their design and calculations "virtual" properties such as changing dynamic stiffness, damping, or mass distribution. In this way, structural elements can be developed which are not subject to any deformation as a result of external forces and, consequently, exhibit an apparently "infinite" stiffness. On the other hand, an interdisciplinary system approach is necessary to implement such adaptive structures. With this approach it becomes possible to equip optimized mechanical structural systems with structure-conforming integrated actuatorics and sensories as well as adaptive control systems offering real-time capability. The technical potentials resulting from this development will considerably broaden the range of new products in the various branches of industry. New developments wiiJ focus on -) Noise and vibration reduction, -) shape control, -) Micro-positioning, which, will lead to quantum leaps in the product development in branches such as -) Traffic engineering, -) Mechanical engineering, -) Optical engineering. -) Medical engineering, and -) Aerospace. However, full advantage from adaptronics as to lightweight structures can only be drawn if the actuator and sensor components are successfully integrated in the structure such that the material and/or structural properties are only negligibly affected if at all (structural conformity and multiftmctionality).