• Title/Summary/Keyword: ultrasonic-wave

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Feasibility study of wide-band low-profile ultrasonic sensor with flexible piezoelectric paint

  • Li, Xin;Zhang, Yunfeng
    • Smart Structures and Systems
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    • v.4 no.5
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    • pp.565-582
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    • 2008
  • This paper presents a feasibility study of flexible piezoelectric paint for use in wide-band low-profile surface-mount or embeddable ultrasonic sensor for in situ structural health monitoring. Piezoelectric paint is a piezoelectric composite with 0-3 connectivity. Because of its ease of application, piezoelectric paint can be readily fabricated into sensing element with complex pattern. This study examines the characteristics of piezoelectric paint in acoustic emission signal and ultrasonic guided wave sensing. A series of ultrasonic tests including pitch catch and pencil break tests were performed to validate the ultrasonic wave sensing capability of piezoelectric paint. The results of finite element simulation of ultrasonic wave propagation, and acoustic emission generated by a pencil lead break on an aluminum plate are also presented in this paper along with corresponding experimental data. Based on the preliminary experimental results, the piezoelectric paint appears to offer a promising sensing material for use in real-time monitoring of crack initiation and propagation in both metallic and composite structures.

Finite Element Analysis of a Particle Manipulation System Using Ultrasonic Standing Wave (정재초음파를 이용한 입자제어 시스템의 유한요소해석)

  • Cho, Seung-Hyun;Park, Jae-Ha;Ahn, Bong-Young;Kim, Ki-Bok
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.20 no.1
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    • pp.3-9
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    • 2010
  • Micro particles in fluid can be manipulated by using ultrasonic standing wave since the ultrasound makes particles move by means of its acoustic radiation force. This work concerns the micro particle manipulation system using ultrasonic standing wave which consists of a microchannel, a reflector, and an ultrasonic transduer. In the present system, the effects of the structural elements should be carefully considered to comprehend the system and find the optimal operational condition. In this investigation, finite element analysis was employed to analyze the system. Some interesting characteristics on the reflector thickness, the channel width, and the operational frequency were observed. Several experimental results were compared with the analytic results. Consequently, this work solidifies the importance of those system parameters and reveals the possibility of various applications of the particle manipulation using ultrasonic standing wave.

The Directivity Measurement of Angle Probe by Photoelastic Visualization Method (광탄성가시화법에 의한 사각탐촉자의 지향성 평가에 관한 연구)

  • Nam, Y.H.;Date, K.
    • Journal of the Korean Society for Nondestructive Testing
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    • v.14 no.2
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    • pp.83-89
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    • 1994
  • It is important for an ultrasonic testing to know the sound pressure field and the directivity of ultrasonic waves propagating in a solid. The directivity of ultrasonic wave is closely related to the sensitivity, the scanning pitch, the arrangement of angle probe, and the defect kind in ultrasonic testing. This paper describes on the directivity measurement of ultrasonic wave using ultrasonic wave visualization method. The directivity of the shear wave emitted from the angle probes were constant during propagation. The difference of directivity was existed between 2MHz and 4MHz angle probes. The centers of directivity were located backward from the incident poing and inside of the angle probe and were not changed during the wave propagation.

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Finite Element Analysis of a Particle Manipulation System Using Ultrasonic Standing Wave (정재초음파를 이용한 입자제어 시스템의 유한요소해석)

  • Cho, Seung-Hyun;Park, Jae-Ha;Ahn, Bong-Young;Kim, Ki-Bok
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2009.04a
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    • pp.565-570
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    • 2009
  • Micro particles in fluid can be manipulated by using ultrasonic standing wave since the ultrasound makes particles move by means of its acoustic radiation force. This work concerns the micro particle manipulation system using ultrasonic standing wave which consists of a microchannel, an adaptive layer, a reflector, and an ultrasonic transduer. In the present system, the effects of the structural elements should be carefully considered to comprehend the system and find the optimal operational condition. In this investigation, finite element analysis was employed to analyze the system. Some interesting characteristics on the reflector thickness, the channel width, and the operational frequency were observed. Several experimental results were compared with the analytic results. Consequently, this work solidifies the importance of those system parameters and reveals the possibility of various applications of the particle manipulation using ultrasonic standing wave.

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Development of Ultrasonic-Optical Fiber Sensor and its Applications (초음파-광섬유 센서의 개발과 그 응용)

  • Oh, Il-Kwon;Lim, Seung-Hyun
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2006.11a
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    • pp.169-174
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    • 2006
  • The outstanding mechanical property of optical fiber and the merits of acoustic emission sensing technique are unified for novel sensor system. The generated ultrasonic wave from piezoelectric generator are propagated along the optical fiber and also sensed. The propagated wave can be influence by external pressure on the optical fiber or environmental circumstance. The optical fiber sensor using ultrasonic wave has advantages compare with existing sensor system. In this study, the sensitivity of the optical fiber sensor is experimentally investigated. As the applications of the optical fiber sensor system using piezoelectric ultrasonic waves, the point load on the optical fiber is measured and the monitoring system for the void fraction of two phase flows is developed. The experimental results show the linear relationship between sensed voltage and void fraction.

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2 D Computer Simulation of Laser-Generated Ultrasonic Wave (레이저 여기 초음파의 2차원 컴퓨터 시뮬레이션)

  • Kim, Gyeong-Jo
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.24 no.7 s.178
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    • pp.1847-1853
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    • 2000
  • A computer simulation technique for 2-dimensional laser generated ultrasonic waves was developed for visualization and investigation of ultrasonic propagation in solids. The technique is similar to a finite difference method (FDM) and a mass-particle model method, but uses a new nodal calculation method based on fundamental consideration of an elastic wave equation. By this method, the propagation behavior oflaser generated ultrasonic wave in thermoelastic and ablation mode is visualized and shows good agreement with previous experimental result or the numerical analysis result by Green function.

Transport Characteristics according to Flexural Beam Shape for the Ultrasonic Transport Systems (초음파 물체 이송시스템에서 Flexural Beam 의 형태 변화에 따른 이송특성에 관한 연구)

  • Shin, Byung-Su;Jeong, Sang-Hwa;Cha, Kyung-Rae
    • Proceedings of the KSME Conference
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    • 2003.11a
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    • pp.1608-1613
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    • 2003
  • In the semiconductor and the optical industry, a new transport system which can replace the conventional sliding system is required. These systems are driven by the magnetic field and the conveyer belt. The magnetic field damages semiconductor and contact force scratches the optical lens. The ultrasonic wave driven system can solve these problems. In this paper, the object transport system using the excitation of ultrasonic wave is proposed. The experiments for finding the optimal excitation frequency, finding phasedifference between two ultrasonic wave generators are performed. The relationship of transporting speed according to the change of flexural beam shape is verified. In addition, the system performance for practical use is evaluated.

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Measurement of Ultrasonic Wave Velocity Changes in Silica-Sand Specimens with Voids (공극을 포함한 실리카샌드 시편의 초음파 속도변화 측정)

  • Kim, Dae-You;Rhim, Hong-Chul;Cho, Youn-Jin
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2017.05a
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    • pp.48-49
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    • 2017
  • In order to examine the effect of voids on the ultrasonic wave velocity, specimens made of Silica-Sand with voids were prepared for the measurements. The volume fraction of 0, 15, and 30% of voids were used to compare the differences. Because of its more homogeneous distribution of materials properties, the Silica-Sand specimens were used, as compared to mortar specimens. The results showed clear change in ultrasonic wave velocity with different volume fraction of voids. This result is to be used for the estimation of the integrity of concrete structures using ultrasonic wave velocity method as nondestructive testing.

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Developement of Efficient Algorithm to Eliminate Aliasing of Ultrasonic Pulsed Wave Doppler Signal (초음파 Pulsed Wave 도플러 신호의 Aliasing 제거를 위한 효율적인 알고리즘 개발)

  • Kim, G.D.;Hwang, J.S.;Ahn, Y.B.;Song, T.K.
    • Proceedings of the KOSOMBE Conference
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    • v.1998 no.11
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    • pp.213-214
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    • 1998
  • The important role of the ultrasonic Doppler system in the modem clinical medicine is to provide the clinical information of the vascular system. The ultrasonic pulsed wave(PW) Doppler system, a kind of the ultrasound Doppler system, is more available than the ultrasonic continuous wave(CW) Doppler system because it can evaluate the velocity and the direction of blood flow as well as the depth of vessel. However, the ultrasonic PW Doppler system has the disadvantage that the range of evaluating velocity of blood flow is limited(Nyquist limit). In order to solve this limit, we propose the algorithm for eliminating this aliasing in this paper. In addition, we propose the efficient signal processing algorithm.

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Characteristics of Particle Separation in Suspension using an Ultrasonic Standing Wave

  • Shin, Beom-Soo;Danao, Mary-Grace C.
    • Journal of Biosystems Engineering
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    • v.37 no.2
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    • pp.113-121
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    • 2012
  • Purpose: Particle separation in solution is one of important process in a unit operation as well as in an extract preparation for biosensors. Contrary to centrifuge-type of mesh-type filter, using an ultrasonic standing wave make the filtering process continuous and free from maintenance. It is needed to investigate the characteristics of particle movement in the ultrasonic standing wave field. Methods: Through the computer simulation the effects of major design and driving parameters on the alignment characteristics of particles were investigated, and a cylindrical chamber with up-stream flow type was devised using two circular-shape PZTs on both sides of the chamber, one for transmitting ultrasonic wave and the other for just reflecting it. Then, the system performance was experimentally investigated as well. Results: The speed of a particle to reach pressure-node plane increased as the acoustic pressure and size of particle increased. The maximum allowable up-stream flow rate could be calculated as well. As expected, exact numbers of pressure-node planes were well formed at specific locations according to the wavelength of ultrasonic wave. As the driving frequency of PZT got close to its resonance frequency, the bands of particles were observed clearer, which meant the particles were trapped into narrower space. Higher excitation voltages to the PZT produced a greater acoustic force with which to trap particles in the pressure-node planes, so that the particles gathered could move upwards without disturbing their alignments even at a higher inlet flow rate. Conclusions: This research showed the feasibility of particle separation in solution in the continuous way by an ultrasonic standing wave. Further study is needed to develop a device to collect or harvest those separated particles.