• Title/Summary/Keyword: Modulus Measurement

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Elastic Moduli and Dissolution Rates of Resorbable Na2O-MgO-P2O5 Bioglasses (Na2O-MgO-P2O5 생체 유리의 탄성계수와 용해도)

  • ;T.D.Taylor
    • Journal of the Korean Ceramic Society
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    • v.26 no.6
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    • pp.850-854
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    • 1989
  • The elastic moduli and dissolution rates of 15 glasses with different mole ratios of sodium-magnasium-phosphate as potential non-toxic biomaterials were investigated. In this study, a 3-pint bending test, sonic resonance technique, and theoretical calculation were used to evaluate the modulus of elasticity. The dissolution rates at 37$^{\circ}C$(human body temperature) were determined by the measurement of mass changes in each sample for 24 weeks.

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Young's Modulus Measurement of Terfenol-D using Strain Gauge (스트레인 게이지를 이용한 Terfenol-D의 영률 측정)

  • Shin, M.S.;Son, De-Rac;Cho, Yook
    • Proceedings of the Korean Magnestics Society Conference
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    • 2002.12a
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    • pp.130-131
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    • 2002
  • Terfenol-D는 상온에서 변형이 가장 큰 재료로 알려져 있고, 자기역학적 결합계수 k$_{33}$=0.75로 매우 높기 때문에 전기에너지를 역학적 에너지로 효율적으로 변환시킬 수 있다[1]. 단점으로는 압축강도는 700 ㎫로 높으나, 인장강도 30 ㎫로 매우 낮아서 재료가 brittle하여 장치 설계 시 세심한 주의가 필요하며, 재료의 상대투자율이 3~10정도로 낮기 때문에 자기폐회로를 구성하는데 어려움이 있다[2-4]. (중략)략)

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Estimation of Measurement Uncertainty in Evaluation of Tensile Properties (인장 물성 측정 불확도 평가)

  • Huh, Y.H.;Lee, H.M.;Kim, D.J.;Park, J.S.
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.34 no.1
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    • pp.73-78
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    • 2010
  • Estimation of tensile properties measurement uncertainty of material was carried out. Sources of uncertainty affecting the measurement of tensile properties were classified and analyzed. The models for uncertainty evaluation of measurands to be determined from tensile test, such as elastic modulus, yield strength and tensile strength, were suggested and derived from the mathematical relations, corresponding to the respective measurands, and the measuring quantities by calculating each sensitivity coefficient of the quantities. Based on these models, the uncertainty of the tensile properties was evaluated from the experimental data of SUS316LN determined according to ISO 6892.

Viscoelastic Properties of Fresh Cement Paste to Study the Flow Behavior

  • Choi, Myoungsung;Park, Kyoungsoo;Oh, Taekeun
    • International Journal of Concrete Structures and Materials
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    • v.10 no.sup3
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    • pp.65-74
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    • 2016
  • During concrete pumping, the migration and redistribution of particles occur in a pipe and the lubrication layer that forms between the bulk concrete and the pipe wall is the governing factor determining the flow behavior. In order to identify flow behavior of pumping, in this study, the viscoelastic properties related to the microstructural behavior of a flocculated suspension were examined by using dynamic oscillatory measurements. Cement paste is assumed to be a constituent material of the lubrication layer and ten cases of mixing design are employed by changing the proportions of mineral admixtures. The relationship between the yield stress obtained from the steady shear test and the dynamic modulus resulted from the oscillatory shear measurement was derived and the implications of the correlation are discussed. Moreover, based on the investigation of the viscoelastic properties with oscillatory measurements, the initial behavior of pumped concrete was analyzed systematically.

Cure Monitoring and Nondestructive Evaluation of Carbon Fiber/Epoxy Composites by the Measurements of Electrical Resistance and AE

  • Lee Sang-Il;Yoon Dong-Jin;Park Joung-Man
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 2004.10a
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    • pp.264-267
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    • 2004
  • Cure monitoring and nondestructive characteristics of carbon fiber/epoxy composites were evaluated by the measurements of electrical resistance and acoustic emission (AE). Logarithmic electrical resistivity of the untreated single-carbon fiber composite increased suddenly to infinity when the fiber fracture occurred, whereas that of the electrodeposited composite increased relatively broadly up to infinity. As curing temperature increased. logarithmic electrical resistivity of steel fiber increased. On the other hand, electrical resistance of carbon fiber decreased due to the intrinsic electrical properties based on the band theory. The apparent modulus of the electrodeposited composite was higher than that of the untreated composite due to the improved interfacial shear strength (IFSS).

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Measurement of Springback Ratio Using Winding Bend Rig (감아굽힘 실험장치를 이용한 스프링백 비의 측정)

  • 김용우
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2000.04a
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    • pp.88-94
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    • 2000
  • A winding bend rig for measurement of springback ratio is made. It measures the bending angles before and after release of bending load which bends specimens with keeping a constant curvature. Thus the springback ratio can be obtained by using this bend rig. Analytical explanations for the spring back are tried by employing simple beam theory. For the analytical calculations with the theory, Young's modulus, fracture strain and stress-strain curve are necessary and these data are obtained from a tensile test. Using both of the beam theory and the results of tensile test, the springback ratio is also calculated. Comparisons of the two springback ratios, one is obtained from bending test and the other from tensile test, show a good agreement.

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Young's Modulus Measurement of FeCoGe/phenol Composites (FeCoGe/페놀 복합체의 영률 측정)

  • Park, K.I.;Kim, H.G.;Shin, K.H.;SaGong, G.
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2003.08a
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    • pp.107-109
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    • 2003
  • The magnetostriction of FeCoGe/phenol composites is measured under the external magnetic field. A few Measurement are carried out by using the electrical-resistance strain gage, the Wheaton Bridge for eliminating the unnecessary voltage, the lock-in-amplifier for the signal amplification and noise filtering. When the external magnetic field is applied to the longitudinal direction against those samples which is the 10wt.% phenol in composites, the theoretical maximum strain of 120ppm is obtained. According to the larger strain than that of others solid state actuators and piezoelectric actuators. FeCoGe/phenol composites could be useful as an actuator.

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Magnetostriction and Young's Modulus Measurement of FeCoGeW/phenol Composites (FeCoGeW/페놀 복합체의 자왜 및 영률 측정)

  • Park, K.I.;Kim, H.G.;Shin, K.H.;SaGong, G.
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2003.11a
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    • pp.325-328
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    • 2003
  • The magnetostriction of FeCoGeW/phenol composites is measured under the external magnetic field. A few Measurement are carried out by using the electrical-resistance strain gage, the Wheaton Bridge for eliminating the unnecessary voltage, the lock-in-amplifier for the signal amplification and noise filtering. When the external magnetic field is applied to the longitudinal direction against those samples which is the 10wt.% phenol in composites, the theoretical maximum strain of 120ppm is obtained. According to the larger strain than that of others solid state actuators and piezoelectric actuators. FeCoGeW/phenol composites could be useful as an actuator.

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Residual Stress Measurement of Flat Welded Specimen by Electronic Speckle Pattern Interferometry (전자처리스페클패턴 간섭법을 이용한 평판 용접시험편의 잔류응력 측정)

  • Chang, Ho-Seob;Kim, Dong-Soo;Jung, Hyun-Chul;Kim, Kyung-Suk
    • Journal of the Korean Society for Nondestructive Testing
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    • v.32 no.2
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    • pp.149-154
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    • 2012
  • The size and distribution of welding residual stress and welding deformation in welding structures have an effect on various sorts of damage like brittle failure, fatigue failure and stress corrosion cracking. So, research for this problem is necessary continuously. In this study, non-destructive technique using laser electronic speckle pattern interferometry, plate of welding specimen according to the external load on the entire behavior of residual stress are presented measurement techniques. Once, welding specimen force tensile loading, using electronic speckle pattern interferometry is measured. welding specimen of base metal and weld zone measure strain from measured result, this using measure elastic modulus. In this study, electronic speckle pattern interferometry use weld zone and base metal parts of the strain differences using were presented in residual stress calculated value, This residual stress value were calculated by numerical calculation. Consequently, weld zone of modulus high approximately 3.7 fold beside base metal and this measured approximately 8.46 MPa.

Anisotropy of Softwood Structural Lumber Using The Elastic Modulus Determined by The Ultrasonic Nondestructive Method (초음파 비파괴 시험법을 이용한 탄성계수의 산정을 통한 침엽수 구조용재의 이방성에 관한 기초연구)

  • Oh, Sei-Chang
    • Journal of the Korean Wood Science and Technology
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    • v.45 no.1
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    • pp.20-27
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    • 2017
  • The aim of this paper is to present the modulus of elasticity of $E_L$, $E_R$, $E_T$ along three principal axis of softwood dimension lumber by nondestructive method. Ultrasonic measurement was carried out on defect free wood samples taken by the Japanese Larch, SPF (spruce-pine-fir) and Hem-fir $2{\times}4s$. The ultrasound velocities were measured to calculate young's moduli and it was derived elastic constants for each wood samples using the ultrasound velocities and densities of wood. From the test, $E_L$ was much greater than $E_R$ and $E_T$. $E_R/E_T$ ratios were about 1.3. The high density wood had high young's moduli in three principal axis and the difference in young's moduli between species was greater in transverse direction than longitudinal direction. The anisotropy of the lumber was presented through the calculated elastic moduli and compliances matrix in diagonal term were determined by inverting the stiffness matrix.