• 제목/요약/키워드: standard specimen

검색결과 692건 처리시간 0.03초

현미경의 길이표준 소급성 확립을 위한 배율 교정 시편 인증 (Certification of magnification standards for the establishment of meter-traceability in microscopy)

  • 김종안;김재완;박병천;엄태봉;강주식
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 2005년도 춘계학술대회 논문집
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    • pp.645-648
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    • 2005
  • Microscopy has enabled the development of many advanced technologies, and higher level microscopic techniques are required according to the increase of research in nano-technology and bio-technology fields. Therefore, in many applications, we need to measure the dimension of micro-scale parts accurately, not just to observe their shapes. To establish the meter-traceability in microscopy, gratings have been widely used as a magnification standard. KRISS provides the certification service of magnification standards using an optical diffractometer and a metrological AFM (MAFM). They are based on different measurement principles, and so can give complementary information for each other. In this paper, we describe the configuration of each system and measurement procedures to certificate grating pitch values of magnification standards. Several measurement results are presented, and the discussion about them are also given. Using the optical diffractometer, we can calibrate a grating specimen with uncertainty of less than 50 pm. The MAFM can measure a grating specimen of down to 100 nm pitch value, and the calibrated values usually have uncertainty less than 500 pm.

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Evaluation Methods for Flat Crush Resistance of Corrugated Fiberboard with Microflutes

  • Youn, Hye-Jung;Kwon, Hyun-Seung;Lee, Hak-Lae
    • 펄프종이기술
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    • 제41권5호
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    • pp.8-14
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    • 2009
  • Corrugated fiberboard is a widely used packaging material because of its high compressive strength and stiffness despite light weight. Corrugated fiberboards with microflutes with height $\leq$ 1.5 mm, such as E, F or G, have been developed. As microflutes have a different geometry from other conventional flutes, they may behave differently in testing and require a new testing method. Therefore, we evaluated the flat crush resistance of corrugated fiberboard with microflutes according to the ISO and TAPPI standard test methods. In addition, the effects of specimen area and platen compression rate were examined. The goal of this study was to identify an appropriate method for flat crush test (FCT) of corrugated fiberboard with microflutes. When a test piece with a standard area was subjected to the FCT in accordance with ISO and TAPPI methods, microflute corrugated fiberboard demonstrated a different load-displacement curve. An area of 20 $cm^2$ was determined to be the most appropriate for FCTof microflute corrugated fiberboard.

알루미늄 폼 복합재료로 된 접합된 DCB 시험편의 구조 해석에 관한 연구 (Study on Structural Analysis of DCB Specimen Bonded with Aluminum Foam Composite)

  • 최해규;김세환;조재웅
    • 한국산학기술학회논문지
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    • 제13권4호
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    • pp.1488-1495
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    • 2012
  • 본 논문에서는 알루미늄 폼 복합재료로 된 DCB(이중외팔보) 시험편의 파괴 거동을 시뮬레이션 해석하였다. 시뮬레이션 해석에 사용된 모델은 영국 공업규격과 ISO국제규격에 의거한 3D 형태로 하였다. 모델의 두께가 두꺼울수록 발생한 크랙의 길이가 길게 나타났고, 높은 하중이 발생하였다. 본 연구에서 얻어진 해석 결과를 알루미늄 폼재질로 접합된 실제 복합재 구조물에 적용시켜 파괴거동을 분석하고 그 기계적인 특성을 파악할 수 있다.

복합초전도체의 자기적 임계온도 측정의 표준화연구 (Magnetic $T_c$ Measurements of Composite Superconductors for a Standard Method)

  • 이규원;김문석;김동호;이상근
    • Progress in Superconductivity
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    • 제6권1호
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    • pp.24-31
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    • 2004
  • Magnetic $T_{c}$ of composite superconductors has been studied for providing a standard method. Various magnetization-temperature curves of NbTi, $Nb_3$Sn and Bi-2223 wires were measured using a SQUID magnetometer. Magnetization-temperature curve of zero-field-cooled procedure showed larger values than fie Id-cooled procedure. To obtain higher resolution near the onset temperature, we employed a two-field-direction method which measures a magnetization-temperature curve of a specimen first in positive and then negative fields. Analytical comparison of the magnetic $T_{c}$, with the resistive T$_{c}$ was accomplished for three specimens. The magnetic $T_{c}$/ mettled showed more detailed information on superconducting state of a specimen than the resistive$T_{c}$/ method. We have also studied the field dependence of the magnetic $T_{c}$ from 5 Oe to 120 Oe, however, no significant difference on field strength was found in our three specimensns

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반복하중 크리프시험에 의한 아스팔트 혼합물의 소성변형특성 평가 (Rutting Potential Evaluation of Asphalt Mixtures by Repeated-Load Creep Test)

  • Zhu L.Y.;Fwa T.F.
    • 한국도로학회논문집
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    • 제8권3호
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    • pp.21-28
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    • 2006
  • Field or laboratory wheel tracking tests have been employed for the evaluation of the rutting potential of asphalt paving mixtures. Compared to field tests, laboratory wheel tracking tests are much less expensive and more manageable for most road projects. However, most test laboratories are not equipped to perform such tests because there does not exist any standard test procedure, and the required equipment is rather expensive. Futhermore, the size of test specimens and the relatively large quantity of test mixture required present difficulties for laboratory specimen mixing and compaction. This paper describes a project conducted to study the feasibility of replacing wheel tracking testsby a repeated-load creep test for rutting potential evaluation. Comparisons were made between the results of the two tests for different test temperatures, loading speeds and applied pressures. Three types of asphalt mixtures were studied in the test program. Favorable conclusions concerning the use of the repeated-load test for rutting potential evaluation were drawn based on the findings of the experimental test results. The correlation between the two types of tests was found to be good for all threeasphalt mixtures. Adopting the repeated-load creep test would lead to cost savings since it employs standard test equipment already available in most laboratories. It would also result in substantial time savings due to the much smaller quantity of mix needed, and the ease in specimen preparation.

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크리프 균열 성장 실험을 위한 소성 변위 결정법 (Plastic Displacement Estimates in Creep Crack Growth Testing)

  • 허남수;윤기봉;김윤재
    • 대한기계학회논문집A
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    • 제30권10호
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    • pp.1219-1226
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    • 2006
  • The ASTM test standard recommends the use of the compact tension specimen for creep crack growth rates measurement. In the creep crack growth rate test, the displacement rate due to creep is obtained by subtracting the contribution of elastic and plastic components from the total load line displacement rate based on displacement partitioning method fur determining $C^*-integral$, which involves Ramberg-Osgood (R-O) fitting procedures. This paper investigates the effect of the R-O fitting procedures on plastic displacement rate estimates in creep crack growth testing, via detailed two-dimensional and three-dimensional finite element analyses of the standard compact tension specimen. Four different R-O fitting procedures are considered; (i) fitting the entire true stress-strain data up to the ultimate tensile strength, (ii) fitting the true stress-strain data from 0.1% strain to 0.8 of the true ultimate strain, (iii) fitting the true stress-strain data only up to 5% strain, and (iv) fitting the engineering stress-strain data. It is found that the last two procedures provide reasonably accurate plastic displacement rates and thus should be recommended in creep crack growth testing. Moreover, several advantages of fitting the engineering stress-strain data over fitting the true stress-strain data only up to 5% strain are discussed.

고로슬래그 미분말 및 순환잔골재를 적용한 PVA섬유 보강 철근콘크리트 보의 구조성능 평가 (Evaluation of Structural Performance of RC Beams retrofitted PVA Fiber to the Change of Replacement Ratio of Recycled Fine Aggregates and Blast Furnace Slag)

  • 하기주;이동렬;하재훈
    • 대한건축학회논문집:구조계
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    • 제34권8호
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    • pp.3-11
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    • 2018
  • In this study, total nine R/C beams, designed by the PVA Fiber with ground granulated blast furnace slag and recycled fine aggregate were constructed and tested under monotonic loading. In the material development, micromechanics was adopted to properly select the optimized range of the composite based on steady-state cracking theory and experimental studies on the matrix and interracial properties. Experimental programs were carried out to improve and evaluate the structural performance of the test specimens: the load-displacement, the failure mode, the maximum strength, and ductility capacity were assessed. Test results showed that test specimens (BSPR-20, 40) was increased the maximum load carrying capacity by 3~6% and the ductility capacity by 9~14% in comparison with the standard specimen (BSS). And the specimens (BSPR-60, 80, 100) was decreased the maximum load carrying capacity by 0~4% and the ductility capacity by 79% in comparison with the standard specimen (BSS) respectively.

산업부산물과 순환잔골재를 적용한 강섬유 보강 철근콘크리트 보의 구조성능 평가 (Evaluation of Structural Performance of Steel Fiber Reinforced Concrete Beams using Industrial By-products and Recycled Fine Aggregates)

  • 하기주;이동렬;하재훈
    • 대한건축학회논문집:구조계
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    • 제34권11호
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    • pp.11-18
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    • 2018
  • In this study, seven R/C beams, designed by the steel fiber with ground granulated blast furnace slag and recycled fine aggregate were constructed and tested under monotonic loading. In the material development, micromechanics was adopted to properly select the optimized range of the composite based on steady-state cracking theory and experimental studies on the matrix and interracial properties. Experimental programs were carried out to improve and evaluate the structural performance of the test specimens: the load-displacement, the failure mode, the maximum strength were assessed. Test results showed that test specimens (BSSR-20, 40, 60, 80) were increased the maximum load carrying capacity by 2~9% and the ductility capacity by 10~22% in comparison with the standard specimen (BSS) respectively. And the specimens (BSSR-100) was decreased the maximum load carrying capacity by 5% and the ductility capacity by 44% in comparison with the standard specimen (BSS) respectively.

4D full-field measurements over the entire loading history: Evaluation of different temporal interpolations

  • Ana Vrgoc;Viktor Kosin;Clement Jailin;Benjamin Smaniotto;Zvonimir Tomicevic;Francois Hild
    • Coupled systems mechanics
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    • 제12권6호
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    • pp.503-517
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    • 2023
  • Standard Digital Volume Correlation (DVC) approaches are based on pattern matching between two reconstructed volumes acquired at different stages. Such frameworks are limited by the number of scans (due to acquisition duration), and time-dependent phenomena can generally not be captured. Projection-based Digital Volume Correlation (P-DVC) measures displacement fields from series of 2D radiographs acquired at different angles and loadings, thus resulting in richer temporal sampling (compared to standard DVC). The sought displacement field is decomposed over a basis of separated variables, namely, temporal and spatial modes. This study utilizes an alternative route in which spatial modes are con-structed via scan-wise DVC, and thus only the temporal amplitudes are sought via P-DVC. This meth-od is applied to a glass fiber mat reinforced polymer specimen containing a machined notch, subjected to in-situ cyclic tension, and imaged via X-Ray Computed Tomography. Different temporal interpolations are exploited. It is shown that utilizing only one DVC displacement field (as spatial mode) was sufficient to properly capture the complex kinematics up to specimen failure.

중.고층 주상복합 R/C 건축물의 단차형 내부 보-기둥 접합부 내진성능평가 (Seismic Performance Evaluation of R/C Different Floor Type Interior Beam-Column Joints in the Middle and High-rise Mixed-use Residential Building)

  • 하기주;신종학;허민행;홍건호;하재훈;남영식
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 2009년도 춘계 학술대회 제21권1호
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    • pp.453-454
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    • 2009
  • 본 연구에서는 중 고층 철근콘크리트 주상복합형 건축물에서 지진하중과 같은 반복하중이 작용할 때 단차형 내부 보-기둥 접합부의 거동 특성을 파악하기 위하여 단차 유무에 따른 내부 보-기둥 접합부 실험체를 대상으로 실험을 실시하여 다음과 같은 결론을 얻었다. 단차가 있는 내부 보-기둥 접합부 실험체는 단차가 없는 표준실험체(FJ-0D)와 비교하여 단차 수준(1.0D, 2.0D)이 증가함에 따라 수평내력과 에너지소산능력이 증가하였고 내부 보-기둥 접합부 영역을 중심으로 균열진전 상황이 상이하였다. 또한 에너지소산능력은 내부 보-기둥 접합부 단차가 높을수록 1.1${\sim}$1.35배 증가하였다.

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