Desenvolvimento e caracterização de um acelerômetro piezoelétrico uniaxial

Abstract

The piezoelectric accelerometer type vibration sensor converts the mechanical vibration of a machine into electrical signals. By analyzing these signals, the structural health of the equipment is monitored, allowing the determination of the best time to take corrective action. This work aims to design, manufacture, and experimentally characterize a prototype of a uniaxial piezoelectric accelerometer, composed of a base mass, piezoelectric ceramic, seismic mass, reading terminal, and enclosure. The sensor was initially modeled in computer-aided design (CAD) software, and the model was computationally simulated, where the mechanical properties were investigated, using Ansys software. The sensor was manufactured, consisting of 1020 carbon steel, piezoelectric ceramic of titanium, zirconium, and lead, and a BNC connector. The electromechanical properties were obtained by impedance spectroscopy. On a self-manufactured test bench, signals from the manufactured sensor and also from a commercial signal analyzer, Fluke 810, were obtained. The experimental and computational properties were compared, as well as the signals from the two sensors. A functional device was obtained, which can be used on a computer with a sound card and a digital frequency counter installed. Two resonance frequencies were detected in the analysis interval. The first occurred at 94.3 kHz, with a percentage deviation of 3.06% with respect to the numerical value of 91.5 kHz. The second occurred at 129.0 kHz, with a percentage deviation of 4.88% with respect to the numerical value of 123.0 kHz. Due to the relatively small deviation, it is possible to determine the resonance frequencies of the sensor only with harmonic analysis. According to the harmonic analysis, the operating range of the sensor was limited to frequencies up to 89.4 kHz. Finally, by comparing the frequency spectra of the accelerometers, the manufactured one showed comparable performance to the commercial accelerometer. For future work, it is recommended to replace the 1020 steel with stainless steel. This would make the sensor corrosion-resistant and able to withstand the industrial environment.