Active Health Monitoring of Composites by Embedded PZT Transducers

The work encompasses a study of interaction between
embedded PZT transducers and composite structures as
well as technique improvement to simplify Lamb waves
analysis. The design of embedded PZT transducers was
improved by reducing the stress concentrations in
composites. The experiments, performed in static
loading, indicated that the embedded PZT transducer
did not significantly reduce the strength of the
composite. Further investigations were conducted to
evaluate the performance of the improved PZT
transducer used as a Lamb wave generator embedded in
composites subjected to mechanical loading. The
tests were performed in static and fatigue loading.
The study showed a large working range of the
embedded PZT transducers. A post processing
technique based on wavelets was developed for damage
assessment. This method focused on the wavelet
coefficients from the Lamb wave response
decomposition, improving the damage detection
capabilities. The other technique was devoted to
filtering the Lamb waves by the use of multi-element
transducers. This technique allowed the reduction of
the effect of a Lamb wave mode towards another

Autorentext

Christophe received his Master of Engineering (Hons) in Mechatronics and a PhD in Electronics from Valenciennes University, France. He also holds a PhD in Aeronautics from the Royal Institute of Technology, Sweden. He worked for FOI in Sweden from 1996 to 2002 on SHM. In 2002 he joined Airbus where he still works as SHM Technology Leader

Klappentext

The work encompasses a study of interaction between embedded PZT transducers and composite structures as well as technique improvement to simplify Lamb waves analysis. The design of embedded PZT transducers was improved by reducing the stress concentrations in composites. The experiments, performed in static loading, indicated that the embedded PZT transducer did not significantly reduce the strength of the composite. Further investigations were conducted to evaluate the performance of the improved PZT transducer used as a Lamb wave generator embedded in composites subjected to mechanical loading. The tests were performed in static and fatigue loading. The study showed a large working range of the embedded PZT transducers. A post processing technique based on wavelets was developed for damage assessment. This method focused on the wavelet coefficients from the Lamb wave response decomposition, improving the damage detection capabilities. The other technique was devoted to filtering the Lamb waves by the use of multi-element transducers. This technique allowed the reduction of the effect of a Lamb wave mode towards another