In PULSE-COM project are investigated several piezoelectric elements to be integrated on the photomobile-polymer (PMP). The two main functions of the piezoelectric layer are:
- Sensing,
- Energy harvesting,
Indeed, when the PMP bends due to light excitation, it is expected the mechanical deformation is converted into electricity by the mean of the direct piezoelectric effect.
To measure the performances of the novel piezoelectric elements developed in PULSE-COM, such as the d31 piezoelectric coefficient, we created a test bench based on the buckling analysis technique.
To validate the method, we tested the bench with a known piezoelectric device, to compare the measured d31 with the manufacturer’s data.
Figure 1: Piezoelectric device using PiezoTech® PVDF material manufactured in collaboration with UGA, cantilever configuration
The piezoelectric device shown on the Figure 1 is placed in a cantilever configuration, meaning one of the extremities is totally clamped while the opposite side is free to move.
In the second configuration, presented on Figure 2, the same device is clamped at both sides and is buckled beforehand. It is then supplied with voltage (converse piezoelectric effect) and the deflection of the central part is measured using a vibrometer laser. The measurements are shown on the Figure 3.
Finally, the d31 piezoelectric coefficient was computed at 7.4 +/- 2.5 pC/N (considering the uncertainties of measurements) while the supplier of the PVDF material specified a value of 6 pC/N which validates the applied method.
Thanks to this test bench validation, we will be able to measure the d31 coefficient of the new piezoelectric elements developed in PULSE-COM. This coefficient will help us create physical models that we will use to design new devices based on the new piezoelectric materials.
Figure 2: Piezoelectric device in blocked-blocked configuration and mechanically buckled.
Figure 3: Stroke at the middle of the piezoelectric sample versus voltage applied on its electrodes.
