• Title/Summary/Keyword: 변형 측정

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Sensitivity Enhancement of Shadow Moiré Technique for Warpage Measurement of Electronic Packages (반도체 패키지의 굽힘변형 측정을 위한 그림자 무아레의 감도향상 기법연구)

  • Lee, Dong-Sun;Joo, Jin-Won
    • Journal of the Microelectronics and Packaging Society
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    • v.22 no.3
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    • pp.57-65
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    • 2015
  • Electronic packages consist of various materials, and as temperature changes, warpage occurs because of the difference in coefficient of thermal expansion. Shadow $moir{\acute{e}}$ is non-contact, whole field measurement technique for out-of-plane displacement. However, the technique has low sensitivity above $50{\mu}m/fringe$, it is not adequate for the warpage measurement in some circumstance. In this paper, by applying phase shifting process to the traditional shadow $moir{\acute{e}}$, measurement system having enhanced sensitivity of $12.5{\mu}m/fringe$ is constructed. Considering Talbot effect, the measurement is carried out in the half Talbot area. Shadow fringe pattern having four times enhanced sensitivity is obtained by the image process with four shadow fringes. The measurement technique is applied to the fibered package substrate and coreless package substrate for measuring warpages at room temperature and at about $100^{\circ}C$.

A Study on Passive Force Control of a Flexible Manipulator (유연 매니퓨레이터의 피동적인 힘 제어에 관한 연구)

  • Kim, Jin-Soo
    • Journal of the Korean Society for Precision Engineering
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    • v.16 no.10
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    • pp.209-216
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    • 1999
  • 일반적으로 힘 제어는 힘 센서의 사용 여부에 따라 능동적 힘 제어와 피동적 힘 제어로 분류시킬 수 있다. 능동적 힘 제어는 힘 세서를 이용하여 구속력을 목표한 힘에 근접하도록 제어한다. 유연 매니퓨레이터의 함수(위치, 속도, 가속도)를 이용하여 일정한 힘에 근접하도록 제어한다. 유연 매티퓨레이터에 있어서 링크 선단의 강성 증대는 힘 제어뿐만이 아니라, 링크의 진동을 크게 유발함으로서 위치 제어에 불리하게 작용한다. 주로 사용되고 있는 힘 센서는 많은 변형 게이지(strain gauge)로 구성되어 있다. 유연 매니퓨레이터 또한 링크 선단의 변형을 측정하기 위해 변형 게이지를 사용하고 있다. 본 논문에서는 이점에 착안하여, 유연 매니퓨레이터의 선단의 탄성 변형을 측정하기 위해 장착한 변형 게이지를 이용한 위치/힘 제어를 제안한다. 먼저, 유연 매니퓨레이터의 집중 정수 모델로부터 링크의 탄성 변형과 구속력 관계를 도출한 후 이 관계를 이용하여 3차원 실험 유연 매니퓨레이터를 실시간 위치/힘 제어 실험을 수행하였다. 또한 범용 동력학 해석 소프트웨어인 ADAMS FEM 을 이용하여 해석하였다. 마지막으로, 실험 결과와 해석 결과를 비교 분석하여 본 논문에서 제안한 유연 매니퓨레이터의 위치/힘 제어의 타당성을 입증시켰다.

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레이져 스페클간섭법에 있어서 스페클 크기와 측정한계에 관한 연구

  • 김경석;양승필;정현철;김정호;이도윤
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1994.10a
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    • pp.521-528
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    • 1994
  • 레이저광의 우수한 가간섭성으로 인해서 거친표면으로 부터 확산된 광에서도 간섭현상을 볼 수가 있다, 이와 같은 레이져광의 독특한 특성으로 인해 나타나는 스페클은 광학적인 간섭계를 사용하여 광을 확산적으로 반사시키는 물체의 변형과 변위, 진동 등을 비접촉적으로 측정 할수 있게 되었다.이와같은 측정법으로써 Holography 간섭법, Speckle 간섭법, Speckle 사집법등이 있으며 비록 이러한 측정법들이 독립적으로 발전되었다 할지라도 기본적인 광학적인 배치와 함수들에 있어서는 유사한 특징을 가지고 있다. 따라서 본 연구에서는 주로 면내변형을 측정하기위한 스페클간섭법에 있어서의 스페클 사이즈와 그에 따른 측정 한계를 확인할 것이다.

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Precision Measurement of Vehicle Shape using Industrial Photogrammetry (산업 사진측량에 의한 자동차의 외형 정밀 측정)

  • 정성혁;박찬홍;이재기
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.22 no.2
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    • pp.179-186
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    • 2004
  • This study describes that the method of precision measurement of vehicle shape and the method of measurement the deformation that it is occurred the reason of accident using industrial photogrammatry. The curved shape is measured using the projection target which is able to acquire the point cloud data. 3D coordinates of the target were able to acquire through object picturing and analysis of coordinates. The acquired point cloud data was done 3D modeling to form the surface with TIN. Also, It able to interpretate a deformation surveying accurately the occurred parts of deformation, then can furnish to the analysis of traffic accident the precise and effective data.

Test Equipment and Test Portfolio for Education of Strain and Vibration Measurements (변형률 및 진동 측정 교육을 위한 실험 장치와 실험 포트폴리오)

  • Yang, Jimin;Lee, Dooyoul
    • Journal of Practical Engineering Education
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    • v.13 no.3
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    • pp.497-505
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    • 2021
  • Test equipment for strain and vibration measurement was designed for educational purposes. Widely available and affordable materials were put into making this device. Three strain gauges placed on an iron ruler made cantilevered beam were used to measure values according to external load. An electromagnet triggered excitation and a function generator created vibration of the beam. We present three different tests conducted with this equipment regarding production of scales, measurement of resonant frequency, and calculation of the difference between excitation frequency and measured frequency. Overall, this paper presents a piece of simple yet inexpensive test equipment and its corresponding portfolio with expectations of being applied to the educational field for efficient measurement of load and vibration.

Anisotropy in Strength and Deformation Properties of a Variety of Sands by Plane Strain Compression Tests(Part II) -Deformation Characteristics at Extremely Small Strain Level (평면변형률압축시험에 의한 각종 모래의 강도.변형특성의 이방성(II)-미소변형률에서의 변형특성 이방성)

  • 박춘식;장정욱
    • Geotechnical Engineering
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    • v.14 no.4
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    • pp.33-46
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    • 1998
  • Anisotropy of stiffness, from extremely small strains to post-failure strains, of isotropically consolidated air-pluviated sands in plane strain compression was studied by using the newly developed instrumentation for small strain measurements. Seven types of sand of the world-wide origins were tested, which have been extensively used for research purposes. Stress-strain at the specimen boundaries. It was found that the maximum Young's modulus $E_{max}$ was irrespective of the angle $\delta$ of the $\delta_1$ direction relative to the bedding plane. However, the normalized$ E_{max}$ was varied with the types of sand. Furthermore, the dependency of the strain and stress level on the stiffness was increased as $\delta$ decreased.

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A Study on the Estimation of the Deformation of Object under Hydrostatic Pressure Test Using Image Processing (영상처리기법을 이용한 내압시험체의 변형도 추정에 관한 연구)

  • Lee, S.G.;Oh, S.W.;Choi, H.J.;Lee, S.H.
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.14 no.4
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    • pp.287-292
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    • 2011
  • To evaluate the pressure-resistant performance of underwater equipment, hyperbaric chamber test facility which can make the hydrostatic pressure is used. In this test, strain gage is generally applied to measure the strain of object under test is suitable for measuring a tiny deformation, but it can not measure a large deformation. Thus this paper suggests a method to estimate the over -order deformation of object under test by the image processing with the image acquired from underwater camera in the hydrostatic test. The main procedure of suggested method comprises the first step to find significant points by processing the image two dimensionally and the second step to estimate a deformation of object under test by tracking the motion of these points. If completing the remained research which is estimating the deformation and comparing it with a real one, it can be a method to measure the over -order deformation of object under test.

용접구조물의 제작시 발생되는 변형사례 모음

  • 배강열;권봉재;김희진
    • Journal of Welding and Joining
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    • v.6 no.1
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    • pp.11-20
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    • 1988
  • 이 글에서는 Butt joint에서 발생되는 가로수축, 각변형 그리고 bowing의 관찰을 통해 mechanism을 서술하였고, box beam, damper blade, bulk head, ball tank, 그리고 cylindrical column 등 실구조물의 변형문제에 접근하여 변형예측, 측정 data제시, 그리고 그 해석을 통해 구조물의 변형 크기를 인식케 하고, 동일한 구조물의 제작에 guide가 되고자 하였다. 변형에 대해서는 일률적인 방지방법이 없기 때문에 우선은 구조물의 제작시마다 변형의 크기와 향상에 대한 예측과 함께 변형계측이 계속되어 data가 축적된다면 차후 그 이용 및 응용 효과는 지대할 것이다.

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Anisotropy in Strength and Deformation Properties of a Variety of Sands by Plane Strain Compression Tests(Part III) -Shear Deformation Characteristics- (평면변형률압축시험에 의한 각종 모래의 강도.변형특성의 이방성(III) -전단변형 특성-)

  • 박춘식;황성춘;장정욱
    • Journal of the Korean Geotechnical Society
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    • v.16 no.4
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    • pp.95-105
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    • 2000
  • Anisotropy of stiffiness, from extremely small strains to post-failure strains, of isotropically consolidated air-pulviated sands in plane strain compression was studied by using the newly developed instrumentation for small strain measurements. Seven types of sand of the world-wide origins were tested, which have been extensively used for research purposes. Stress-strain relationships for a wide range of strain from about 0.0001% to 10% were obtained with measuring axial and lateral strains locally free from the effects of bedding and membrane penetration errors at the specimen boundaries. It was found that the maximum shear modulus Gmax was irrespective of the angle $\delta$of the $\sigma$1 direction relative to the bedding plane. However, the normalized Gmax was varied with the types of sand. Furthermore, the dependency of the strain and stress level on the stiffness increased as decreased.

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