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The present work has been initiated in the frame of the European research project DREAM. Within this highly
interdisciplinary project we are focusing on the development and application of vibration damping solutions
based on piezoelectric shunt circuits for future aeroelastic applications.
The scientific community has put significant effort into the investigation of piezoelectric shunt damping in
conjuction with typical engineering test structures such as beams and plates. However, investigations are mainly
restricted to surface bonded piezoelectric elements. Commercially available actuators and sensors can be easily
bonded to structures using standard epoxy resins. Yet, the structural integration into composite laminates
is cumbersome, due to the implications in terms of overall structural integrity and functionality, and due to
the problems in achieving a good electrical conductivity, intimate contact betwen electrode and piezoceramic
material as well as a perfect isolation from the surrounding host structure. This contribution is concerned with
technological aspects related to the integration of piezoceramic actuators into highly loaded CFRP structures.
In particular, we present results of a comparative study aiming at the characterization of less invasive electrodes
to establish electrical contact between the piezoceramic material and possible shunt circuits.
Another drawback of commercial actuators are their limited strain allowables ranging from 0.1% to 0.3% which
is not sufficient for high performance lighweight structures. The second part of this contribution is therefore
dedicated to the description of a novel prestressing procedure which is used to fabricate actuators that command
170% higher strain allowables than non-prestressed actuators. Mechanical testing of these prestressed actuators
are very encouraging, showing high strain allowables, perfect electrical isolation from the host structure, excellent electric contacting of the piezoelectric material and reliable functionality even when applied to curved structures.
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