• Title/Summary/Keyword: Ultrasonic measurement

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Thickness Measurement of A Thin Layer Using Plane Ultrasonic waves (평면 초음파를 이용한 미소 간극 측정)

  • 김노유
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1995.10a
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    • pp.415-418
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    • 1995
  • This paper describes a new technique for thickness measurement of a very thin layer less than one-quarter of the wavelength of ultrasonic wave using ultrasonic pulse-echo method. The technique determines the thickness of a thin layer in a layered medium form the amplitudes of the total reflected waves from the back side layer of interst. Thickness of a very thin layer few inch deep inside the media can be measured without using a very high frequency ultrasonic transducer over 100MHz which must be used in the conventional techniques for the precision measurement of a thin layer. The method also requires no inversion process to extract the thickness from the waveform of the reflected waves, so that it makes possible on-line measurement of the thickness of the layer.

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A Study on the Ultrasonic Technique for Measurement of Vibration in Journal Bearing (저어널 베어링의 진동 계측을 위한 초음파 응용 기술에 관한 연구)

  • 김노유
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 1999.10a
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    • pp.476-481
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    • 1999
  • This paper describes a new technique for measurement of the displacement less than one-quarter of the wavelength of ultrasonic wave using ultrasonic pulse-echo method. The technique determines the displacement of a journal bearing from the amplitudes of the total reflected waves from the surface of journal inside the bearing. Vibration of journal bearing can be measured without using a very high frequency ultrasonic transduce over 100MHz which must be used in the conventional techniques for the precision measurement of a small displacement. The method also requires no inversion process to extract the thickness from the waveforms of the reflected waves, so that it makes possible on-line measurement of the vibration of journal bearing.

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Complete Modeling of an Ultrasonic NDE Measurement System - An Electroacoustic Measurement Model

  • Dang, Changjiu;Lester W. Schmerr, Jr.
    • Journal of the Korean Society for Nondestructive Testing
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    • v.21 no.1
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    • pp.1-21
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    • 2001
  • It will be shown how models can simulate all the elements of an ultrasonic NDE measurement system, including the pulser/receiver, cabling, transducer(s), and the acoustic/elastic waves fields. When combined, these models form what is called the electroacoustic measurement model. It will be demonstrated how this electroacoustic measurement model can be used to conduct parametric transducer and system studies and how the model can form the basis for experimentally characterizing all the elements of the ultrasonic measurement system, using purely electrical measurements.

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Torque Measurement System of Piezoelectric Ultrasonic Motor (압전 초음파 전동기의 토크측정 시스템)

  • Kim, Young-Gyoon;Kim, Jin-Soo
    • Proceedings of the KIEE Conference
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    • 1999.07d
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    • pp.1780-1782
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    • 1999
  • The ultrasonic motor used here is the windmill type ultrasonic motor operated by single-phase AC source. A metal-ceramic composite component was used as the stator element to generate ultrasonic vibrations. The windmill type ultrasonic motors has only three components; a stator element of two wind-mill shape slotted metal endcaps, a rotor and a bearing. In this paper we proposed a system for torque measurement of piezoelectric ultrasonic motor.

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A Study on the Ultrasonic Measurement for Damage Evaluation of Power Plant Bearing (발전용 베어링 손상평가를 위한 초음파 측정 연구)

  • Lee, Sang-Guk
    • Proceedings of the KSME Conference
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    • 2004.11a
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    • pp.1727-1732
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    • 2004
  • For the purpose of monitoring by ultrasonic test of the ball bearing conditions in rotating machinery, a system for their diagnosis was developed. ultrasonic technique is used to detect abnormal conditions in the bearing system. And various data such as frequency spectrum, energy and amplitude of ultrasonic signals, and ultrasonic parameters were acquired during experiments with the simulated ball bearing system. Based on the above results and practical application for power plant, algorithms and judgement criteria for diagnosis system was established.

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Study on Non-contact Ultrasonic Transducer for Measurement of Fruit Firmness (과실 경도측정을 위한 비접촉 초음파 변환기 연구)

  • Lee, Sang-Dae;Ha, Tae-Hoon;Kim, Ki-Bok;Kim, Man-Soo
    • Journal of Biosystems Engineering
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    • v.35 no.3
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    • pp.189-196
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    • 2010
  • This study was conducted to develop an non-contact ultrasonic transducer for measurement of fruit firmness. The center frequency of non-contact ultrasonic transducer was 500 kHz. As an active element of non-contact ultrasonic transducer, the 1-3 piezoelectric composite material was selected. That material has high piezoelectric properties such as electro-mechanical coupling factor, $k_t$ and piezoelectric voltage constant, $d_{33}$ and also that material has low acoustical impedance which enables to matching the acoustical impedances between piezoelectric material and air. As a front matching material between 1-3 piezoelectric composite material and air, various kinds of paper with different thickness were tested. To control the dead-zone of the fabricated non-contact ultrasonic transducer, the backing material composed of epoxy resin and tungsten powder were made and evaluated. The fabricated non-contact ultrasonic transducer for fruit showed that the cneter frequency, bandwidth and beamwidth were approximately 480 kHz, 30 % and 12 mm, respectively. It was concluded that non-contact measurement of apple firmness would be possible by using the fabricated non-contact ultrasonic transducer.

Development of Robust Single Ultrasonic Module for Distance Measurement of Mobile Robot (이동로봇의 거리측정을 위한 고성능 일체형 초음파 모듈 개발)

  • Choi, Jong-Hoon;Shim, Hyeon-Min;Ryu, Je-Goon;Lee, Eung-Hyuk
    • Proceedings of the KIEE Conference
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    • 2005.10b
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    • pp.418-420
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    • 2005
  • This paper proposed ultrasonic distance measurement module development for correct distance detection with collision escaping or obstacle of mobile robot is traveling self-regulation. Representative ultrasonic module applied in existing was Polaroid company's 6500 series and Devantech company's SRF04/SRF08 series. This ultrasonic sensors are corrupted by systematic errors due mainly to the dependency of sound speed upon surrounding conditions and random errors of uncertain origin. Therefore Ultrasonic distance detecting means of error compensation method and high definition, narrow beam angle, board area distance detecting means to apply to ultrasonic mobile robot control urgently need. In this paper use internal type temperature compensation method to improve problem of ultrasonic distance measurement method instead of that volume that have shortcoming of used correct temperature compensation methods applied big addition device. Compensate error by environment change of temperature. Humidity density etc. and is applicable to mobile robot offering various interface and real-time processing developed possible distance measurement module.

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Application of the Through-Transmitted Ultrasonic Signal for the Identification of Two-Phase Flow Patterns in a Simulated High Temperature Vertical Channel

  • Chu In-Cheol;Song Chul-Hwa;Baek Won-Pil
    • Nuclear Engineering and Technology
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    • v.36 no.1
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    • pp.12-23
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    • 2004
  • In the present study a new measurement technique has been developed, which uses an ultrasonic transmission signal in order to identify the vertical two phase flow pattern. The ultrasonic measurement system developed in the present study not only provides the information required for the identification of vertical two phase flow patterns but also makes real time identification possible. Various vertical two phase flow patterns such as bubbly, slug, churn, annular flow etc. have been accurately identified with the present ultrasonic measurement system under atmospheric condition. In addition, the present test apparatus can practically simulate the ultrasonic propagation characteristics under high temperature and high pressure systems. Therefore, it is expected that the present ultrasonic flow pattern identification technique could be applicable to the vertical two phase flow systems under high temperature and high pressure conditions.

Simultaneous Measurement of Ultrasonic Velocity and Thickness of Isotropic and Homogeneous Solids Using Two Transducers (두개의 탐촉자를 사용한 등방성 균일 고체의 초음파 속도 및 두께 동시 측정법)

  • Lee, Jeong-Ki;Kwon, Jin-O;Kim, Young-H.
    • Journal of the Korean Society for Nondestructive Testing
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    • v.19 no.5
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    • pp.363-368
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    • 1999
  • Ultrasonic pulse-echo methods measuring the transit time through specimens have been widely used in determination of ultrasonic velocity and thickness of specimens. Usually, to determine the velocity of the ultrasonic. the transit time of the ultrasonic pulse through specimen is measured by using the ultrasonic measuring equipment such as the oscilloscope including ultrasonic pulser/receiver and the thickness of the specimen is measured by using the length measuring instrument such as micrometer or vernier calipers etc., i. e. each parameter is measured by using each measuring method. In the case of the measuring the thickness of a specimen by using the ultrasonics. the ultrasonic equipments, which measure the thickness, such as the ultrasonic thickness gauge must be calibrated by using the reference block of which the ultrasonic velocity is known beforehand. In the present work, we proposed a new method for simultaneous measurement of ultrasonic velocity and thickness without reference blocks. Experimental results for several specimens show that proposed method have good agreements with those by traditional ultrasonic method.

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Uncertainty Analysis for the Multi-path Ultrasonic Flowmeter UR- 1000 with Dry Calibration (간접 교정에 의한 다회선 초음파유량계 UR-1000 불확도 분석)

  • Hwang, Shang-Yoon;Park, Sung-Ha;Park, Kyung-Am
    • 유체기계공업학회:학술대회논문집
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    • 2002.12a
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    • pp.378-386
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    • 2002
  • Multi-path ultrasonic Sow measurement system uncertainty is determined by assigning an expected error of each component of flow measurement and then defining the total flow measurement uncertainty as square root of the sum of squared values of the individual error. Sources of uncertainty for flow measurement are geometry, transit time and velocity profile integration uncertainty. A theoretical uncertainty model for multi-path ultrasonic transit time flowmeter configured with parallel 5 chords, is derived from and calculated by dry calibration method.

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