The integrity of piezo-composite beams under high cyclic electro-mechanical loads - experimental results

摘要

The present research is a part of a comprehensive experimental study dealing with the structural integrity of smart structures. A laminated composite beam made of graphite-epoxy and having a quasi-isotropic lay-up was used as a host structure for all the piezoelectric patches. Two commercially available piezoelectric patches (PZT-5H, lead zirconate titanate) were employed in the present test series: ACX patches from QP15N Cymer Inc., USA and PIC255 from PI Ceramics, Germany. The first part of the study investigates the behaviour of piezo-laminated beams with embedded or surface bonded patches, subjected to axial tension/compression loads. Seven different specimens (numbered as AX-EM) with embedded piezoceramic patches and another two specimens (numbered as AX-SM) with four piezoceramic patches bonded to the surface of each host structure (one pair of ACX and one pair of PIC-255 patches) were tested. The second part of the present study investigates the behaviour of seven specimens (numbered as BEN1-7) with four piezoelectric patches, one pair of ACX and one pair of PIC-255, bonded on each side of the host structure. These specimens were subjected to cyclic bending moments using a four-point bending test set-up. The degradation in the sensing abilities of the piezoelectric patches due to an increasing number of electro-mechanical load cycles was monitored and recorded.