Abstract
The use of thin monolithic piezoceramic patches as actuators and sensors for adaptive structures is well known and has been described in literature. Nevertheless the manufacturing of adaptive structures is still very challenging. During the manufacturing process it is often necessary to apply high mechanical loads on the extreme brittle piezoceramic material. As a result very often cracks in the piezoceramic material make the structure uselessness. This problem becomes serious when large scale structures with many actuators and sensors are considered. To come to more reliable results the use of encapsulated piezoceramic actuators and sensors came into focus. Within the German industrial project “Adaptronik” a new modular concept has been developed to pre-encapsulate different kinds of piezoceramic materials before further processing. During this manufacturing step the piezoceramic material is provided with a mechanical stabilization, an electrical insulation, electrodes and reliable electric contacts. The multifunctional elements are characterized by an increased damage tolerance, good long term properties and an easy handling. Due to the modular concept, the multifunctional elements can be designed to meet a great variety of different requirements. This involves for example driving voltages, size and shape of the elements and the piezoceramic material itself. The manufacturing of curved elements was demonstrated. A technology to bond these elements on spatial curved surfaces and to integrate them into fiber composite structures was developed. Experiments have been carried out to investigate the active and passive properties of the multifunctional elements and their interaction with structural components.
