• Title/Summary/Keyword: 변형률 게이지

Search Result 92, Processing Time 0.03 seconds

Investigation on the Vibrating Wire Strain Gauges for the Evaluation of Pipeline Safety in Extreme Cold Region (극한지 파이프라인 안정성 평가를 위한 진동현식 변형률 게이지 연구)

  • Kim, Hak Joon
    • The Journal of Engineering Geology
    • /
    • v.26 no.4
    • /
    • pp.583-591
    • /
    • 2016
  • Vibrating wire (VW) strain gauges are widely used for the evaluation of pipeline safety in extreme cold region. The development of VW strain gauges for the low temperature environment is necessary because of the high cost of gauges sold in developed countries. Thermistors embedded in the regular VW strain gauges and PT 100 sensors embedded in the gauges specially manufactured for this study have gone through credibility tests for temperature measurements. The use of PT 100 is recommended at low temperature environments because thermistors have low credibility at temperatures below $-15^{\circ}C$. Strain measurements using regular VW strain gauges also show low accuracies as temperature goes down. VW strain gauges manufactured using inconel give high credibility of strain measurements at low temperatures. More reliable VW strain gauges for the low temperature environment will be developed in the near future.

Investigation on the Credibility of the Vibrating Wire Strain Gauges used for the Tunnel Instrumentation (터널 진동현식 변형률 게이지의 신뢰성 시험 연구)

  • Kim, Hak-Joon;Park, Chan
    • The Journal of Engineering Geology
    • /
    • v.18 no.2
    • /
    • pp.153-158
    • /
    • 2008
  • Vibrating-wire strain gauges are widely used for the tunnel instrumentation because of the long-term stability at humid environments. Domestic strain gauges are mainly used in Korea due to the high cost of the foreign strain gauges. The credibility of the domestic strain gauges is not properly proven even though strain gauges produced by many different companies are available in the markets. The purpose of this paper is to investigate the credibility of the 2.5" strain gauges by using a laboratory compression test.

그래핀을 이용한 투명 변형율 센서

  • Bae, Sang-Hun;Lee, Yeong-Bin;Kim, Jae-Hyeon;An, Jong-Hyeon
    • Proceedings of the Materials Research Society of Korea Conference
    • /
    • 2012.05a
    • /
    • pp.91.1-91.1
    • /
    • 2012
  • 그래핀의 우수한 기계적 물성에 관한 연구가 보고된 이후 그래핀의 기계적 특성을 이용한 다양한 어플리케이션에 관한 연구가 진행되고 있다. 기계적 특성을 이용한 다양한 어플리케이션 중 가장 대표적인 것은 발생한 스트레인을 측정하는 스트레인 게이지일 것이다. 때문에 본 연구에서는 다양한 기계적 활용 방안 중 스트레인 게이지를 목표로 그래핀을 이용한 스트레인 게이지의 가능성에 관한 실험을 진행하였다. 먼저 그래핀 내에서의 Piezo-resistive 효과에 관한 기초 테스트를 진행을 통해 그래핀의 gauge factor 수치가 2.5가량이 나옴을 확인하였다. 이 때 사용된 그래핀의 경우 Ni 촉매층을 이용하여 CVD 장비를 이용하여 사용되었고 7%의 투과도를 보였다. 추가적으로 이 같은 그래핀의 Piezo-resistive 특성을 이용하여 우리는 두 종류의 변형률 센서를 제작하였다. 한 가지는 기존의 단일 게이지의 경우 미리 지정된 방향의 변형률 정도만을 측정할 수 있다는 단점을 극복하기 위한 rosette 형태의 스트레인 게이지를 제작함으로써 변형률 뿐만 아니라 표면에서 발생하는 주변형률의 방향을 측정할 수 있었다. 또한 제작된 스트레인 센서를 장갑위에 부착 함으로써 다가올 입는 형태의 전사소자에 응용이 가능한 모양의 변형률 센서 제작에 성공하였다.

  • PDF

Strain Analysis by Measured Displacement Data (측정 변위를 이용한 변형률 해석)

  • Kim, Tae Nam
    • Journal of the Korea institute for structural maintenance and inspection
    • /
    • v.6 no.4
    • /
    • pp.147-155
    • /
    • 2002
  • To find the safety and serviceability of bridges, it must consider the behaviour of structural member and evaluation of the exact resistance of the member subjected to external loads. To evaluate the behaviour and the resistance of the structural member, it must measure the strains and displacements of the structures. Usually we use the strain gauge to measure the strains. When, the bridge is long span and high pier, the setting of strain gauge is very difficult and not economic. It is not recommendable for the use of strain gauge, when the structural member has many cracks and moisture. Thus, to make up for this demerits, the algorithm of strain analysis by measured displacements data is proposed.

Fabrication of a Temperature-Compensating FBB Sensor for Measurement of Mechanical Strain (온도 보상형 Double FBG센서의 제작과 기계적 변형률 측정시험)

  • Jung, Dal-Woo;Kwon, Il-Bum;Choi, Nak-Sam
    • Journal of the Korean Society for Nondestructive Testing
    • /
    • v.25 no.5
    • /
    • pp.356-361
    • /
    • 2005
  • A temperature-compensating double fiber Bragg grating(FBG) sensor having two different FBGs in one fiber line was proposed for real time measurement of mechanical normal strain in structures. Measurement of mechanical strains of the aluminum beam surface by the double FBG sensor was performed under various thermal conditions, and the results were compared with those of electrical resistance strain gage. The FBG sensor fabricated in this study was able to measure accurately the mechanical strains without containing any thermal strain component.

The Apparent Strains of Strain Gages in Cryogenic Environment (극저온 환경에서 스트레인 게이지의 겉보기 변형률 특성에 관한 연구)

  • 주진원;김갑순
    • Transactions of the Korean Society of Mechanical Engineers
    • /
    • v.16 no.6
    • /
    • pp.1099-1107
    • /
    • 1992
  • The apparent strain of temperature self-compensated strain gages at cryogenic temperature is presented. By joining the international round robin test on electrical strain gages at cryogenic temperatures, apparent strain curves of up to the fourth order with respect to the temperature are obtained with different strain gages and different materials. The liquid nitrogen and the liquid helium are employed to get the cryogenic environment. The results can be effectively utilized to determine the real strains by mechanical loading at cryogenic temperature. This paper also describes the optimal selection of strain gages and test materials for the use of strain gages at cryogenic temperature.

Development of Fiber Optic Total Reflected Extrinsic Fabry-Perot Interferometric Sensor for Structural Strain Measurement (구조물의 변형률 측정을 위한 광섬유 TR-EFPI 센서의 개발)

  • Kwon, In-Bum;Choi, Man-Yong;Moon, Hahn-Gue;Kim, Min-Soo
    • Journal of Sensor Science and Technology
    • /
    • v.9 no.2
    • /
    • pp.96-105
    • /
    • 2000
  • Fiber optic TR-EFPI(total reflected extrtinsic Fabry-Perot interferometric) sensor was developed to measure the strain of structures, such as building, bridge, aircraft, etc. It has been difficult to distinguish the increase and decrease of the strain from the conventional fiber optic EFPI sensor because their signals only have a sinusoidal wave pattern related to the change of strain. Also, the absolute strain could not be measured by the simple fiber optic EFPI sensor. In this study, in order to measure the magnitude of strain with the direction of strain, the fiber optic sensor was simply constructed with the total reflected EFPI sensor probe. This probe was manufactured with a single mode fiber and a mirror coated fiber in a silica glass capillary tube. The output signal of this fiber optic TR-EFPT sensor can give the information about the magnitude and the direction of strain. The loading-unloading test was performed by the universal testing machine with alluminum beam specimen to compare the strain from fiber optic TR-EFPI sensor with the value from electrical strain gauge. In the result of this experiment. the strain from fiber optic TR-EFPI sensor had a good agreement with the values from the electrical strain gauge.

  • PDF

The Characteristic Test for Gage Factors of Strain Gages in Cryogenic Environment (극저온 환경에서 스트레인 게이지의 게이지상수 및 변형률 측정에 관한 연구)

  • 김갑순;주진원
    • Transactions of the Korean Society of Mechanical Engineers
    • /
    • v.17 no.9
    • /
    • pp.2205-2213
    • /
    • 1993
  • The characteristic test for gage factors of temperature self-compensated strain gages at cryogenic temperature is presented. By joining the international round robin test on electrical strain gages at cryogenic temperatures, the gage factors of three kinds of widely-used strain gages are obtained at the room temperature, the temperatures of liquid nitrogen and liquid helium. The calibration system which produce precise bending strain is by mechanical loading at cryogenic temperature. This paper also presents the creep characteristic of strain gages at maximum strain level.

Understanding the Principles of Wheatstone Bridge Circuit (휘트스톤 브리지 회로의 원리에 대한 이해)

  • Choi, Byung-Hee;Ryu, Chang-Ha
    • Explosives and Blasting
    • /
    • v.35 no.2
    • /
    • pp.9-17
    • /
    • 2017
  • The Wheatstone bridge is an important electrical circuit that is widely used to measure extremely small resistance changes in strain gages. The strain gages are attached to the structure or specimen whose deformation is to be detected. The Wheatstone bridge finds one of its major applications in the areas of static and dynamic strength tests for various engineering materials. In the split Hopkinson pressure bar (SHPB) system, for example, the bridge circuit is required to measure the dynamic strains of the incident and transmitted bars along which the stress wave propagates. In this article, the principles of the Wheatstone bridge circuit are in detail explained for easy reference during laboratory experiments associated with rock dynamics. Especially, the circuit arrangements of the quater, half, and full bridges are presented with their basic uses.

Development of Analysis Tool for Structural Behavior of Domestic Containment Building with Grouted Tendon (CANDU-type) (국내 부착식 텐던 격납건물(CANDU형)의 구조거동 분석 도구 개발)

  • Lee, Sang-Keun;Song, Young-Chul
    • KSCE Journal of Civil and Environmental Engineering Research
    • /
    • v.26 no.5A
    • /
    • pp.901-908
    • /
    • 2006
  • The structural integrity of containment building in Nuclear Power Plants has to be verified by the ISI(In Service Inspection) because there are some variations on the structural behavior of it due to the change of the physical properties of concrete and tendon with the lapse of time. In this study, the program 'SAPONC-CANDU' which can monitor and analyze the structural behavior of the containment building with grouted tendon (CANDU-type, 'Wolsong unit-2, 3, and 4' in Korea) was developed. This program is based on the algorithm which can calculate the prediction values of the quantities of strain variation for the vibrating-wire strain gauges embedded into the concrete of the containment building under temperature and time dependent factors which are creep, shrinkage, and prestressing force. The readings of the strain gauges are used as input data for the operation of the program. And it finally provides graphically a prediction value, line and band of the quantity of strain variation for the respective strain gauges, therefore, it is thought that the site engineers are able to assess the structural integrity of the domestic containment building with grouted tendon with easy using this program.