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CRC/TR 39: Production technologies for light metal and fiber reinforced composite based components with integrated piezoceramic sensors and actuators
Sub-project B1

Subproject B1

Shaping of Piezo-Metall-Composites

Coordinators:

Prof. Dr.-Ing. habil. Prof. E. h. Dr.-Ing. E. h. Dr. h.c. Reimund Neugebauer
Fraunhofer Institut for Machine Tools and Forming Technology IWU
Reichenhainer Straße 88
09126 Chemnitz

Telephon: +49-(0)371 / 5391-1401
Telefax: +49-(0)371 / 5391-1404
E-Mail: reimund.neugebauer@iwu.fraunhofer.de


PD Dr.-Ing. Lutz Lachmann
Fraunhofer Institut für Werkzeugmaschinen und Umformtechnik IWU
Reichenhainer Straße 88
09126 Chemnitz

Telephon: +49-(0)371 / 531-35109
Telefax: +49-(0)371 / 531-23509
E-Mail: lutz.lachmann@iwu.fraunhofer.de

Contact

Dipl.-Ing. Matthias Nestler
Fraunhofer Institut für Werkzeugmaschinen und Umformtechnik IWU
Abteilung Blechbearbeitung
Reichenhainer Str. 88
09126 Chemnitz

Telephon: +49-(0)371 / 5397-1263
Telefax: +49-(0)371 / 5397-1298
E-Mail: matthias.nestler@iwu.fraunhofer.de

Presenting the Research Program

Motivation and objective of research

The integration of piezoceramics e. g. Macro-Fibre-Composites (MFC) in metal-structures offers the possibility to achieve different functionalities like a reduction of vibrations or structural health monitoring. The use in a high volume production e. g. automotive industry is only possible with an appropriate production technology. The time- and cost-intensive subsequent application of sensors and actors on shaped sheet metals has to be avoided.

Methods

In order to achieve this aim the approach is the fabrication of double layer sheets with an integration of piezo modules using an adhesive joint method. The forming of the double layer composites is performed in a jellied condition of adhesive, the hardening finishes after the forming process. So this method leads to a considerable reduction of tensile stresses in the piezoceramic module and allows the elastic forming of brittle piezoceramic fibres. Consequently it is possible to fabricate two- and three-dimensional shaped geometries.

Results

It was shown that the presented method allows the forming of brittle piezo fibres. Therefore bending, deep drawing and stretch drawing operations have been performed. For the characterisation of functionality different methods were investigated. It has become evident that the measurement of capacitance as well as the x-ray analysis are very good indicators for a forming induced damage of the piezo module. Furthermore the test of sensor and actor functionality allows an application oriented characterisation. The simulation of the forming process as well as the loading of the piezo fibres was performed in TP B2.
 












Figure 1:
Forming tool for rectangular cup

 












Figure 2:
Rectangular cup with R250
   






Figure 3:
Micrograph of bending specimen R10

Research programme

Based on positive results of the forming of double layer sheets with integrated piezo modules the aim is a further development of this technology for a later use in a high volume production. Objective of research is the characterisation of the deformability behaviour of composites with global and local applied commercial and non-commercial modules under variation of the top layer and the type of piezo module. Forming tests in combination with a test of functionality allow the identification of an optimal design.
The investigation of degradation behaviour of the piezo modules is performed by simulation and experiment in subproject B2. This allows to draw conclusions about the residual functionality of the piezo module after performing the forming operation.
By the use of piezo modules developed in subproject A5 or A6 an improvement of the contacting and a reduction of preparation time in comparison to commercial modules is planned to be performed.
The forming of micro-structured piezo-metal-composites (subproject A2) is planned with a reduced transfer of stresses and strains into the forming zone. Therefore a tool has to be developed, which avoids the expansion of the micro-cavities during the forming process.

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