• 제목/요약/키워드: Ultrasonic measurement

검색결과 835건 처리시간 0.025초

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

  • 김노유
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 1995년도 추계학술대회 논문집
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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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저어널 베어링의 진동 계측을 위한 초음파 응용 기술에 관한 연구 (A Study on the Ultrasonic Technique for Measurement of Vibration in Journal Bearing)

  • 김노유
    • 한국공작기계학회:학술대회논문집
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    • 한국공작기계학회 1999년도 추계학술대회 논문집 - 한국공작기계학회
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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.
    • 비파괴검사학회지
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    • 제21권1호
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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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압전 초음파 전동기의 토크측정 시스템 (Torque Measurement System of Piezoelectric Ultrasonic Motor)

  • 김영균;김진수
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1999년도 하계학술대회 논문집 D
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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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발전용 베어링 손상평가를 위한 초음파 측정 연구 (A Study on the Ultrasonic Measurement for Damage Evaluation of Power Plant Bearing)

  • 이상국
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2004년도 추계학술대회
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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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과실 경도측정을 위한 비접촉 초음파 변환기 연구 (Study on Non-contact Ultrasonic Transducer for Measurement of Fruit Firmness)

  • 이상대;하태훈;김기복;김만수
    • Journal of Biosystems Engineering
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    • 제35권3호
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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.

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

  • 최종훈;심현민;유제군;이응혁
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2005년도 학술대회 논문집 정보 및 제어부문
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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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    • 제36권1호
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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.

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

  • 이정기;권진오;김영환
    • 비파괴검사학회지
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    • 제19권5호
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    • pp.363-368
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    • 1999
  • 시험체의 두께나 초음파 속도를 측정하기 위해서 초음파 펄스-에코법이 널리 사용되고 있다. 초음파 속도를 결정하기 위해서는 초음파 송수신 장치를 포함한 오실로스코우프와 같은 초음파 측정 장치를 사용하여 시험편에서의 초음파진행 시간을 측정하고, 초음파 진행 거리에 해당하는 시험편의 두께를 버어니어 캘리퍼스 또는 마이크로미터와 같은 길이측정 도구를 사용하여 측정한다. 그리고 초음파를 이용하여 시험편의 두께를 측정할 때에는 초음파 속도를 알고 있는 대비 시험편으로 기준을 설정하여야 한다. 본 연구에서는, 대비 시험편 없이 재료의 두께와 초음파 속도를 동시에 구하는 방법을 제시하였다. 재질과 두께를 달리한 여러 시험편에서 측정된 초음파 속도와 두께가 기존의 방법에 의해 측정한 값과 잘 일치하였다.

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

  • 황상윤;박성하;박경암
    • 유체기계공업학회:학술대회논문집
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    • 유체기계공업학회 2002년도 유체기계 연구개발 발표회 논문집
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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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