Development of a New PEA Cell for Model Cables

In this work, a prototype of a new PEA cell configuration has been built and its principle of operation investigated and described. The reasons that led the authors to this work are due to the fact that the traditional cell still presents some issues. In particular, it known that that for cable specimens the reflection phenomenon and the signal attenuation are the main responsible factors that affecting the main output signal. Concerning the acoustic wave attenuation phenomenon, it was found that the signal magnitude can increase by replacing the metallic ground electrode with a polymeric acoustic coupler and the PVDF absorber with a metallic block. Based on this, after a description of the classic and the new PEA cell structure, in the present paper the acoustic wave behavior in the sensor/absorber interface has been simulated by means of a previously developed model. Simulation results show that in the new PEA cell the signal sensed by piezoelectric sensor is doubled in comparison with that detected in the traditional configuration. However, in the first experimental test carried out with the built PEA cell prototype in a model cable specimen it has been observed that the magnitude of the space charge profile needs to be further improved.