Piezoelectric films for high frequency ultrasonic transducers in biomedical applications

Zhou, Qifa; Lau, Sien-Ting; Wu, Dawei; Shung, K. Kirk

doi:10.1016/j.pmatsci.2010.09.001

Cited by 313 publications

(219 citation statements)

References 130 publications

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“…High frequency transducers are used for practical reasons because they offer an opportunity for smaller packaging, such as through the use of MEMS piezoelectric transducers, since the active element thickness is inversely proportional to ultrasonic wavelength. 9 In this work, the changes in state of charge and state of health are linked to variations in the first arrival time of the high frequency ultrasonic wave. According to elastic wave propagation theory, the wave propagation speed depends upon the bulk modulus, shear modulus, and density within a material.…”

mentioning

confidence: 99%

State of Charge and State of Health Estimation Using Electrochemical Acoustic Time of Flight Analysis

Davies

Knehr

Tassell³

et al. 2017

J. Electrochem. Soc.

155

103

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Ultrasonic analysis was used to predict the state of charge and state of health of lithium-ion pouch cells that have been cycled for several hundred cycles. The repeatable ultrasonic trends are reduced to two key metrics: time of flight shift and total signal amplitude, which are then used with voltage data in a supervised machine learning technique to build a model for state of charge (SOC) prediction. Using this model, cell SOC is predicted to ∼1% accuracy for both lithium cobalt oxide and lithium iron phosphate cells. Elastic wave propagation theory is used to explain that the changes in ultrasonic signal are related to changes in the material properties of the active materials (i.e., elastic modulus and density) during cycling. Finally, we show the machine learning model can accurately predict cell state of health with an error ∼1%. This is accomplished by extending the data inputs into the model to include full ultrasonic waveforms at top of charge. A key component of an electric vehicle is the battery management system (BMS), which is responsible for controlling the operating conditions on a given battery cell (or stack of cells) in order to optimize the performance and lifetime of the full battery system. The most effective battery management systems must be able to track battery state of charge (SOC), state of health (SOH) and cell failure, including early prediction of catastrophic failure. Despite the importance of this task, being able to reliably determine SOC, SOH and failure at low cost still presents a significant challenge. A range of methods exist at present, however the simplest methods can prove inaccurate, and more complex methods are not suitable for low-cost, in-operando SOC determination. 1-3For instance, in its most common implementation, SOC prediction consists of voltage monitoring (direct measurement) combined with coulomb-counting (book-keeping).1 This can present challenges for a variety of reasons. First, for voltage measurements, the flatness of voltage readings over the majority of battery capacity, especially for lithium iron phosphate (LFP) cells, presents difficulties. 4 Furthermore, voltage fade, changing cell impedances, and varying discharge rates impact measured voltage, obscuring true SOC. Second, coulomb counting is also an inexact science, as discharge rate, environmental factors such as temperature, and cell degradation can all impact the actual capacity for any given discharge. This can lead to a cycle of abuse, whereby discharge conditions lead to an incorrect estimate of SOC, and therefore the cell becomes inadvertently over-discharged. This causes damage to the cell, which leads to further inaccuracy in the SOC prediction, resulting in continued over-discharging and cell damage. Effectively, a battery "death-spiral" ensues.One method to further increase the accuracy of battery management systems is to introduce a technique that can directly measure the physical state of the battery to enhance the determination of SOC, SOH, and cell failure, especially when applied i...

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mentioning

confidence: 99%

State of Charge and State of Health Estimation Using Electrochemical Acoustic Time of Flight Analysis

Davies

Knehr

Tassell³

et al. 2017

J. Electrochem. Soc.

155

103

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“…1 Using this type of thickness resonant mode transducer to generate ultrasonic waves in a fluid is straightforward, despite the significant acoustic impedance mismatch. It is more difficult to obtain high detection sensitivity, due to the large mismatch between the acoustic impedance of the transducer and the fluid.…”

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confidence: 99%

The electro-mechanical behaviour of flexural ultrasonic transducers

Dixon

Kang

Ginestier

et al. 2017

Applied Physics Letters

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Flexural ultrasonic transducers are capable of high electro-mechanical coupling efficiencies for the generation or detection of ultrasound in fluids. They are the most common type of ultrasonic sensor, commonly used in parking sensors, because the devices are efficient, robust, and inexpensive. The simplest design consists of a piezoelectric disc, bonded to the inner surface of a metal cap, the face of which provides a vibrating membrane for the generation or detection of ultrasonic waves in fluids. Experimental measurements demonstrate that during the excitation of the piezoelectric element by an electrical voltage, there are three characteristic regions, where the frequency of the emitted ultrasonic wave changes during the excitation, steady-state, and the final decay process. A simple mechanical analogue model is capable of describing this behaviour. V C 2017 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license

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“…It is also of applied benefit for structural acoustics engineers interested in improvement of low-frequency sound radiation characteristics of thick piezo-composite smart circular plates in the face of uncertainties. 15,19,[41][42] These elements are of realistic concern in advancement of intelligent micro-electromechanical systems, 43,44 for which precise movement control is essential. It can readily be combined with the classical passive control methods 1,2,45,46 and/or expediently be augmented with multiple pairs of electroded piezoelectric actuator/sensor segments in a multi-input multi-output (MIMO) active control framework [47][48][49] to effectively deal with the medium-and high-frequency acoustic radiation problems.…”

Section: Introductionmentioning

confidence: 99%

Robust active sound radiation control of a piezo-laminated composite circular plate of arbitrary thickness based on the exact 3D elasticity model

Hasheminejad

Keshavarzpour

2016

Journal of Low Frequency Noise, Vibration and Active Control

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A multi-objective mixed H 2 /H 1 robust output feedback control synthesis with regional pole placement constraints in a linear matrix inequalities framework is adopted for active low-frequency sound radiation control of an arbitrarily thick, rigidly baffled, simply supported, multi-layered piezo-composite circular panel. The adopted control system concurrently captures the benefits of both H 2 transient control performance and H 1 robust stability in the face of external disturbances and system uncertainties. Also, the implemented volumetric sensing/actuation configuration avoids the typical problems associated with conventional (spatially discrete) piezoelectric sensor/actuator patches, where the total volume velocity can be effectively cancelled with the main contribution being to the long wavelength acoustic power emission. The elasto-acoustic analysis is based on the spatial state-space method in the context of exact 3D elasticity theory along with the Rayleigh integral formula where Neumann's addition theorem is incorporated in the associated Hankel transform representation to arrive at a computationally efficient expression for the nonaxisymmetric pressure field within the acoustic half-space, valid in both near and far fields. Subspace system identification of the fully coupled structure-fluid interaction problem is performed, and the truncated modes are considered as multiplicative uncertainties in synthesis of the mixed-norm controller. Numerical simulations establish the ability of the implemented volumetric sensing/actuation methodology in cooperation with the multi-objective robust active control scheme for restraining low-frequency sound radiation from a Ba 2 NaNb 5 O 15 /steel/PZT4 circular piezo-laminated plate, without provoking instability of the closed-loop system. Also, superior bandwidth frequency and tracking performance in comparison to the H 2 and H 1 controllers are observed. This work is believed to be the first such attempt to exactly model (and actively control) the 3D nonaxisymmetric acousto-elastodynamic frequency response of an arbitrarily thick, smart piezo-laminated circular plate in heavy fluid loading condition (i.e. without using any kind of far-field, low-frequency, and/or light fluid coupling approximations), with straightforward extensibility for any arbitrary through-thickness variation of distributed material properties.

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Piezoelectric films for high frequency ultrasonic transducers in biomedical applications

Cited by 313 publications

References 130 publications

State of Charge and State of Health Estimation Using Electrochemical Acoustic Time of Flight Analysis

State of Charge and State of Health Estimation Using Electrochemical Acoustic Time of Flight Analysis

The electro-mechanical behaviour of flexural ultrasonic transducers

Robust active sound radiation control of a piezo-laminated composite circular plate of arbitrary thickness based on the exact 3D elasticity model

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