On the Generation of High-Frequency Acoustic Energy with Polyvinylidene Fluoride

Swartz, R.G.; Plummer, J. D.

doi:10.1109/t-su.1980.31193

Cited by 57 publications

(10 citation statements)

References 11 publications

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“…It can be observed from the table that for a constant stack thickness of 110 microns, stack having more number of layers with smaller layer thickness yields better central deflection of the diaphragm. This inference is in line with that of earlier research work where acoustic power outputs with multiplelayer stack are studied (Swartz and Plummer 1980).…”

Section: Multilayer Actuationsupporting

confidence: 92%

Modeling of single and multilayer polyvinylidene fluoride film for micro pump actuation

2009

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Micro pumps are essential components of micro devices such as drug delivery systems. Large numbers of pumps have been proposed based on different actuating principles. Piezoelectric actuation offers advantages such as reliability and energy efficiency. Lead zirconate titanate (PZT) based piezoelectric actuation for micro pumps is predominantly explored despite its disadvantages such as brittle nature, low straining and difficulties in processing. Polymer piezoelectric materials like polyvinylidene fluoride (PVDF) could be promising replacements for PZT owing to their availability in form of films and good strain coefficients. Very limited literature on micro pump with PVDF as an actuator is available. In this paper, finite element analysis (FEA) model of a micro pump actuator using single and multilayer PVDF for actuation is developed in ANSYS Ò . The model takes into account the influence of driving voltage and actuator geometry. The central deflection of the pump diaphragm which is instrumental in defining the pump performance is studied for driving voltages of 100-200 V. The deflection of the pump diaphragm for single layer and multilayer actuation are determined from the model. It could be inferred from the initial part of the study that pump performance depends on driving voltage and actuator film thickness. In order to reduce driving voltage requirement multilayer stacked actuator is tried with four different configurations of the layers. It is concluded that stacking configuration of parallel energized straight polarity PVDF layers yielded best central deflection. An attempt is made to compare the performance of multilayer actuator with an equivalent single thick layer actuator. It is noticed that the multilayer actuator performance was better by about 101% when number of layers is doubled.

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Section: Multilayer Actuationsupporting

confidence: 92%

Modeling of single and multilayer polyvinylidene fluoride film for micro pump actuation

2009

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“…Thus, the two PVDF films were connected electrically in parallel and acoustically in series with their piezoelectric polarization directions antiparallel. The double-layer PVDF films configuration reduces the input electrical impedance of the sensor, which consequently increases the intensity of the output ultrasonic wave from the available driving voltage source [ 102 ]. A flexible brass film for electromagnetic shielding to reduce the environmental noises and a polyimide film for WUS structure protection and electrical insulation were applied to wrap the entire structure of WUS except for the ultrasonic sensing area where the ultrasound is transmitted or received.…”

Section: Methodsmentioning

confidence: 99%

Ultrasound Measurement of Skeletal Muscle Contractile Parameters Using Flexible and Wearable Single-Element Ultrasonic Sensor

AlMohimeed

Ono

2020

Sensors

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Skeletal muscle is considered as a near-constant volume system, and the contractions of the muscle are related to the changes in tissue thickness. Assessment of the skeletal muscle contractile parameters such as maximum contraction thickness ( T h ), contraction time ( T c ), contraction velocity ( V c ), sustain time ( T s ), and half-relaxation ( T r ) provides valuable information for various medical applications. This paper presents a single-element wearable ultrasonic sensor (WUS) and a method to measure the skeletal muscle contractile parameters in A-mode ultrasonic data acquisition. The developed WUS was made of double-layer polyvinylidene fluoride (PVDF) piezoelectric polymer films with a simple and low-cost fabrication process. A flexible, lightweight, thin, and small size WUS would provide a secure attachment to the skin surface without affecting the muscle contraction dynamics of interest. The developed WUS was employed to monitor the contractions of gastrocnemius (GC) muscle of a human subject. The GC muscle contractions were evoked by the electrical muscle stimulation (EMS) at varying EMS frequencies from 2 Hz up to 30 Hz. The tissue thickness changes due to the muscle contractions were measured by utilizing a time-of-flight method in the ultrasonic through-transmission mode. The developed WUS demonstrated the capability to monitor the tissue thickness changes during the unfused and fused tetanic contractions. The tetanic progression level was quantitatively assessed using the parameter of the fusion index (FI) obtained. In addition, the contractile parameters ( T h , T c , V c , T s , and T r ) were successfully extracted from the measured tissue thickness changes. In addition, the unfused and fused tetanus frequencies were estimated from the obtained FI-EMS frequency curve. The WUS and ultrasonic method proposed in this study could be a valuable tool for inexpensive, non-invasive, and continuous monitoring of the skeletal muscle contractile properties.

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“…Piezoelectric plastics like polyvinylidene fluoride (PVDF) are better matched to the low acoustic impedance of liquids or plastics. Unfortunately, PVDF is less sensitive than ceramic [17,18].…”

Section: Introductionmentioning

confidence: 99%

Electromechanical properties of magnetite transducer

Tawfik

Elsharif

2004

Journal of Magnetism and Magnetic Materials

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On the Generation of High-Frequency Acoustic Energy with Polyvinylidene Fluoride

Cited by 57 publications

References 11 publications

Modeling of single and multilayer polyvinylidene fluoride film for micro pump actuation

Modeling of single and multilayer polyvinylidene fluoride film for micro pump actuation

Ultrasound Measurement of Skeletal Muscle Contractile Parameters Using Flexible and Wearable Single-Element Ultrasonic Sensor

Electromechanical properties of magnetite transducer

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