Piezoelectric film sensors for the cavitation impact measurement

Menghuot Phan

Master's thesis

Abstract:

Piezoelectric sensors based on the thin piezoelectric polyvinylidene fluoride (PVDF) polymer films are developed and fabricated to measure the interaction magnitude between the cavitating field and the material surface. In this thesis, PVDF sensors ware fabricated by photolithography processes. Kapton tape was tested to protect the sensors from the cavitation damage. The sensors developed within the thesis and commercial variants of the sensors were compared and analyzed. The drop ball calibration technique was used to set the sensitivity of the sensors to the impact forces. Four different ball-masses three and different drop heights were tested during the calibration. The relationship between the time duration of the signal generated by the sensors and the initial drop high in the calibration method was also analyzed. The different sizes and protective layer configurations of the PVDF sensor were prepared and tested. The developed PVDF sensor was successfully applied to the measurement of the acoustic cavitation field generated by ultrasonic horn proving higher sensitivity than commercial variant.

Abstract:

Piezoelectric sensors based on the thin piezoelectric polyvinylidene fluoride (PVDF) polymer films are developed and fabricated to measure the interaction magnitude between the cavitating field and the material surface. In this thesis, PVDF sensors ware fabricated by photolithography processes. Kapton tape was tested to protect the sensors from the cavitation damage. The sensors developed within the thesis and commercial variants of the sensors were compared and analyzed. The drop ball calibration technique was used to set the sensitivity of the sensors to the impact forces. Four different ball-masses three and different drop heights were tested during the calibration. The relationship between the time duration of the signal generated by the sensors and the initial drop high in the calibration method was also analyzed. The different sizes and protective layer configurations of the PVDF sensor were prepared and tested. The developed PVDF sensor was successfully applied to the measurement of the acoustic cavitation field generated by ultrasonic horn proving higher sensitivity than commercial variant.

Keywords

cavitation, collapse, PVDF sensor, photolithography

Language used: English

Date on which the thesis was submitted / produced: 12. 6. 2020

Thesis defence

• Supervisor: Ing. Miloš Müller, Ph.D.

Technical University of Liberec

Faculty of Mechanical Engineering

Master programme / field:
Mechanical Engineering / Machines and Equipment Design