<title>Comparison of adaptronic microsystems based on piezoelectric fibers for general use or for the utilization in prepreg FRP</title>

Abstract

The field of ,,Adaptronics" combines sensor and actuator effects with electronics. The components furnished with adaptronics shall sense relevant properties and shall adapt in an intelligent way -they shall ,,feel, think and act". For instance, one application is the active vibration compensation of dynamically stressed structures.So far, adaptronics utilises actuators -and partly also sensors -in the mm size range which possess a substantial stiffhess. If such actuators! sensors were to be integrated into light weight structures -e.g. an carbon fibre reinforced aeroplane part or a glass fibre reinforced robot arm -the light weight structures would be severely affected in their advantageous properties. If, however, these specific properties are to be maintained, the actuators! sensors have to feature a small volume and stiffness.The micro manufacturing of such systems is an activity of the Fraunhofer Institute IFAM. The approach chosen includes the utilisation of piezo electric fibres in the diameter range from 20 jim -200j.tm. The micro systems consist of many fibres being contacted by interdigitated electrodes made of electrically conductive adhesives. In addition, structural adhesives and casting polymers are used. These actuator! sensor modules can be both applied onto structures, or integrated into structures. The performance of the different modules will be compared. An interesting approach for the use of sensor!actuator modules especially in prepreg fibre reinforced plastics is to also make the PZT fibre modules in a prepreg state.The presentation will feature the latest results of the developments regarding both, the manufacture and the performance ofcured as well as ofprepreg modules.

Ferroelectric Characterization of Single PZT Fibers

“…Finally, the green fibers are thermally debound and sintered at temperatures up to 12008C. With these techniques, fiber diameters down to 15, 30 and 80 mm can be fabricated using the VSSP, the ALCERU, or the extrusion process, respectively (Bystricky, 2000;Vorbach et al, 2001;Gesang et al, 2002).…”

“…However, none of these authors has given any validation for their measurements. Otherwise, the fibers are tested in a composite structure (Gesang et al, 2002;Nelson et al, 2003) where the fiber properties are extracted from the composite response and symbolize an average value of a multiplicity of fibers. To the knowledge of the authors, Nelson and co-workers (2003) were the first to characterize and compare all commercially available fibers using 1-3 composites, and they found VSSP fibers performed best in terms of free-strain, polarization, coercive field, and hysteresis.…”

<title>New results and future plans of the German major project ADAPTRONICS</title>

“…As actuator thicker fibers have to be used (e.g. 400 jim fibers from Smart Material Corp.) [4]. The PZT patches are pre-encapsulated with a protective skin with a copper mesh as electrical lead, producing a highly reliable component with a large damage tolerance.…”

Reliability of piezoceramic patch sensors under cyclic mechanical loading

“…The structures of the two sensor types investigated are schematically shown in figures 1 and 2. The sensors with embedded piezoceramic foils and fibres of the PZT (lead-zirconate-titanate) system were developed and realized by DLR in Braunschweig and by Fraunhofer IFAM in Bremen [Ges00,Ges02], respectively. The manufacture of the PZT-foil sensors is described in more detail in an accompanying article of this issue [Wie03].…”