Finite Element Simulation of a Composite Piezoelectric Ultrasonic Transducer

Kagawa, Y.; Yamabuchi, Tatsuo

doi:10.1109/t-su.1979.31071

Cited by 63 publications

(26 citation statements)

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“…The numerical results are obtained by using a commercial FEM package, ANSYS 6.1. Since the whole bending actuator is symmetric in circumferential direction, only a wedge-shaped part of it with fixing and symmetric boundary conditions is considered for the calculation [53]. A 3-D tetrahedral structural solid element type, Solid-92 is chosen to model the passive plate and a 3-D tetrahedral coupled-field solid element type, Solid-98 is chosen to model the PZT layer.…”

Section: Verification By Numerical Simulation and Experimental Measurmentioning

confidence: 99%

06/00145 Valveless piezoelectric micropump for fueldelivery in direct methanol fuel cell (DMFC) devices

2006

Fuel and Energy Abstracts

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Presented in this dissertation is the study of a novel fuel delivery system combined with miniaturized direct methanol fuel cell (DMFC). The core component of this system is a valveless micropump driven by ring-type piezoelectric bending actuator. By applying an alternating electrical field across the actuator, the resultant reciprocating movement of the pump diaphragm can be converted into pumping effect. Nozzle/diffuser elements are used to direct the flow. To make the power system applicable for portable electronic devices, the micropump needs to meet some specific requirements: low power consumption but sufficient fuel flow rate. In this study, both theoretical and experimental methods have been used to investigate the effects of materials properties, actuator dimensions, driving voltage, driving frequency, nozzle/diffuser dimension, and other factors on the performance of the whole system. As a result, a viable design of micropump system for fuel delivery in DMFC devices has been achieved and some further improvements are suggested.In the beginning of this dissertation, the history, working principle, types, and current research status of both fuel cell and micropump are reviewed. Following this comprehensive introduction, the research objective to develop a novel portable power system that combines fuel cell technology and micropump technology is presented. To help design such a system, a series of analytical models are established to estimate the deflection, volume change, flow rate, and power iv consumption of the micropump. Both finite element method (FEM) and experimental method are applied to verify the models. Based on the analytical analysis, material properties and dimensions of the micropump actuator are optimized to obtain maximum flow rate and minimum power consumption. Later a separated micropump prototype has been fabricated and tested. It is observed that the performance of a DMFC device is improved by using this micropump to supply fuel. In addition, the electrochemical impedance analysis of this fuel cell device is conducted to try to understand the reasons for the performance improvement. Finally, the accomplishments of this study are summarized and future perspective is provided.v

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Section: Verification By Numerical Simulation and Experimental Measurmentioning

confidence: 99%

06/00145 Valveless piezoelectric micropump for fueldelivery in direct methanol fuel cell (DMFC) devices

2006

Fuel and Energy Abstracts

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“…Numerical simulations were used to demonstrate design performance. The simulations included all the elements required, including the transducer characteristics, the ultrasound phenomena, and water, the transmission medium [31][32][33][34][35]. It was observed that channel volume and medium density affected the ratio of energy penetration to energy loss.…”

Section: Introductionmentioning

confidence: 99%

A novel sound-blocking structure based on the muffler principle for rib-sparing transcostal high-intensity focused ultrasound treatment

Chao

Hsu

et al. 2015

International Journal of Hyperthermia

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(2015) A novel sound-blocking structure based on the muffler principle for rib-sparing transcostal high-intensity focused ultrasound treatment, International Journal of Hyperthermia, 31:5, 507-527, DOI: 10.3109/02656736.2015 AbstractThe main challenge in transcostal high-intensity focused ultrasound therapy is minimising heat deposition in the ribs while ensuring that a sufficient dose is delivered to the target region. Current approaches rely on expensive multichannel phased-array systems to turn the individual transducer on and off according to either geometrical arrangements or complicated wave calculations. To protect the ribs from heating, the ultrasound energy must not only not reach the ribs, but must also not accumulate in front of the ribs. The research in this paper proposes a different approach, of attaching a sound-blocking structure in front of the rib cage with similar effects to those of an engine exhaust muffler. The sound-blocking structure is based on the muffler principle to prevent ultrasound energy from reaching the ribs and reduce the amount of energy reflected back to the applicator. Finite element simulations with a 0.5-MHz transducer of the overall sound fields and temperature distribution showed that the ultrasound pressure and energy level would decrease behind the novel sound-blocking structures, thereby resulting in a lower temperature at the ribs than at the tumour. Without the protecting structure, the rib temperature reached 104.19 C whereas with the structure it reached only 37.86 C. An experimental set-up using porcine ribs with a phantom was also developed to validate the concept, which showed that the rib temperature reached 73 C without protection within 1 min of ablation time whereas it reached 36.5 C with the device. The tumour region in the tests reached 51C and 49 C with and without protection, respectively.

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“…Only few papers are devoted to the strict mathematical analysis of the above named problems. In the following papers mainly are obtained numerical results (see [13], [15], [16]). In the present paper for boundary-transmission problems generated by the above mentioned mathematical model, we prove the existence and uniqueness theorems in Sobolev-Slobodetski spaces.…”

Section: Introductionmentioning

confidence: 99%

Mathematical problems of interaction of different dimensional physical fields

Chkadua

2013

J. Phys.: Conf. Ser.

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Abstract. In the paper we consider mathematical problem of interaction of different dimensional physical fields for complex composite structures. We investigate the mixed transmission problem arising in the model of fluid-solid acoustic interaction when a piezo-ceramic elastic body (Ω + ) is embedded in an unbounded fluid (Ω − ). The corresponding physical process is described by boundary-transmission problems for second order partial differential equations. In particular, in the bounded domain Ω + we have 4 × 4 dimensional matrix strongly elliptic second order partial differential equation, while in the unbounded complement domain Ω − we have a scalar Helmholtz equation describing an acoustic wave propagation. The physical kinematic and dynamic relations mathematically are described by appropriate boundary and transmission conditions. With the help of the potential method and theory of pseudodifferential equations the uniqueness and existence theorems are proved in Sobolev-Slobodetski spaces.

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Finite Element Simulation of a Composite Piezoelectric Ultrasonic Transducer

Cited by 63 publications

References 0 publications

06/00145 Valveless piezoelectric micropump for fueldelivery in direct methanol fuel cell (DMFC) devices

06/00145 Valveless piezoelectric micropump for fueldelivery in direct methanol fuel cell (DMFC) devices

A novel sound-blocking structure based on the muffler principle for rib-sparing transcostal high-intensity focused ultrasound treatment

Mathematical problems of interaction of different dimensional physical fields

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