A Methodology for Reconstructing Source Properties of a Conical Piezoelectric Actuator Using Array-Based Methods

Abstract

We investigated the force produced by a conical piezoelectric (PZT, lead zirconate titanate) transducer actuated by high voltage pulses (HVP) in contact with a steel transfer plate. Using elastic wave propagation theory in a semi-infinite plate, we aimed to quantify the magnitude and estimate the shape of the force–time function via the body waves produced in the transfer plate using the displacement field recorded on an array of 20 absolutely calibrated PZT receivers. We first calibrated the receiver array using glass capillary fracture. We proceeded to use a conical PZT transducer to actively produce a source at the origin, allowing us to study the displacement field produced on the now calibrated PZT receiver array. We studied two types of HVP: An impulsive and step source. The calibrated receiver array was used to estimate the general shape of the force–time functions for each type of HVP. From our hypothesized force–time functions we were able to estimate the peak force produced by the PZT actuator: The impulsive source generated a force of $$f_{peak} = 2.90 \pm 0.42$$ f peak = 2.90 ± 0.42 N and the step source generated $$f_{peak} = 1.79 \pm 0.30$$ f peak = 1.79 ± 0.30 N, respectively, for a peak applied voltage of 273 V. This translates to an applied force of $$\sim $$ ∼ 0.011 N/V and 0.007 N/V for the impulse and step force–time functions, respectively, which is similar to estimates found in the literature for other conical transducers in contact with metallic transfer media. This measurement was verified directly by independent measurements of the peak force $$f_{peak}$$ f peak using a dynamic force transducer. We found that our methodology correctly estimated the magnitude of the force but is limited to transducers with incident angles $$\theta<$$ θ < 53$$^{\circ }$$ ∘ . Beyond this angle, overestimates of the force were observed due to the lack of body wave energy produced by the source. These results allow us to quantitatively determine the forces produced by active PZT techniques using only the measurement of the displacement field captured on a calibrated conical PZT array. Quantitative understanding of active PZT sources additionally constrains the transfer functions approach, which is commonly used in the non-destructive testing of materials and in other fields, such as rock physics and laboratory seismology.

Elastic immersive wave experimentation

“…First, the piezoelectric actuator tends to oscillate and emit ringing wavefields into the rock medium after being driven by a voltage signal of finite duration. I believe this oscillation is caused by the lack of the backing mass, which is a critical component of a piezoelectric transducer (Selvadurai et al, 2022;Glaser et al, 1998;Proctor, 1982). Without such a backing mass, the piezoelectric elements will unavoidably oscillate due to remaining motions or momentum, which needs to be damped as fast as possible after the input voltage is removed (Sinkevicius & Baskys, 2019;Vengelis et al, 2019).…”

Laboratory Acousto‐Mechanical Study Into Moisture‐Induced Reduction of Fracture Stiffness in Granite

“…(2023) with its minor axis R 1 given as: $$${R}_{1}=\frac{1}{2}\sqrt{\lambda L+\frac{{\lambda }^{2}}{4}}.$$$ where λ is the wavelength and L is the T‐R distance (65 mm). Ultrasonic pulses are emitted from the transmitter using a 200 V excitation voltage (P. A. Selvadurai et al., 2022; Wu et al., 2020, 2021). A survey is conducted every 15 min with 1,144 measurements obtained over 286 hr.…”

“…Ultrasonic pulses are emitted from the transmitter using a 200 V excitation voltage (P. A. Selvadurai et al, 2022;Wu et al, 2020Wu et al, , 2021. A survey is conducted every 15 min with 1,144 measurements obtained over 286 hr.…”

A Study of Progressive Failure in Porous Rocks Using Numerical and Experimental Modeling

“…The rock failure test is conducted using LabQuake, a stateof-the-art triaxial apparatus for geo-mechanical testing of both soft and hard rocks located in the Rock Physics and Mechanics Laboratory at ETH Zurich, Switzerland. To detect acoustic emissions, this machine is equipped with in-house developed conical-type piezo-electric transducers, which are absolutely calibrated and exhibit a flat, broadband response between 100 kHz and 1.5 MHz (Proctor, 1982; Glaser et al, 1998;McLaskey and Glaser, 2012;McLaskey et al, 2015;Selvadurai et al, 2022) and which are designed to resist high pressures and temperatures. AE data are continuously recorded with a sampling frequency of 10 MHz by a data acquisition system designed by the Swiss company Elsys AG, which also allows for tomographic surveys using a pulsing unit (HVP, Elsys Instruments AE-HV-MUX) that consists of a Piezosystem Jena voltage amplifier for the generation of pulses (HVP 1000/200) (Selvadurai et al, 2022).…”

“…To detect acoustic emissions, this machine is equipped with in-house developed conical-type piezo-electric transducers, which are absolutely calibrated and exhibit a flat, broadband response between 100 kHz and 1.5 MHz (Proctor, 1982; Glaser et al, 1998;McLaskey and Glaser, 2012;McLaskey et al, 2015;Selvadurai et al, 2022) and which are designed to resist high pressures and temperatures. AE data are continuously recorded with a sampling frequency of 10 MHz by a data acquisition system designed by the Swiss company Elsys AG, which also allows for tomographic surveys using a pulsing unit (HVP, Elsys Instruments AE-HV-MUX) that consists of a Piezosystem Jena voltage amplifier for the generation of pulses (HVP 1000/200) (Selvadurai et al, 2022). Three linear variable differential transformers (LVDTs) mounted equally apart around the sample in the interior of the LabQuake cell are employed to measure axial strain throughout the experiment with a sampling frequency of 1 second.…”