• Title/Summary/Keyword: elastic modulus equation

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Determining Shear Modulus of 3-ply Laminated Veneer Lumber by Uniaxial Tension Test

  • Oh, Sei-Chang
    • Journal of the Korean Wood Science and Technology
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    • v.41 no.5
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    • pp.425-431
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    • 2013
  • Estimation equations of shear modulus in the plane of laminated veneer lumber (LVL) were compared each other through uniaxial tension test results. The equations - basic elastic equation in the dimensional orthotropic case, Hankinson's formula and empirical equation proposed by Salikis and Falk, were applied to determine the elastic constants at various angles to the grain, which were needed for determination of shear modulus. Tensile elastic modulus of LVL predicted from these equations were compared with test data to evaluate the accuracy of the equation. Tensile elastic modulus rapidly decreased at orientations between 0 and 15 degrees and elastic modulus at grain angles of 15, 30, and 45 degrees overestimated in the presented equations. But the proposed equation by Salikis and Falk showed better prediction, especially at 30, and 45 degrees. This proposed formula would be more useful and practical for estimating of shear modulus of wood composites like LVL to minimize the effect of Poisson's ratio term.

A Proposal of an Elastic Modulus Equation for High-Strength and Ultra High-Strength Concrete

  • Jang, II-Young;Park, Hoon-Kyu;Yoon, Young-Soo
    • International Journal of Concrete Structures and Materials
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    • v.18 no.1E
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    • pp.43-48
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    • 2006
  • This paper presents an elastic modulus equation more appropriate for predicting the elastic modulus of structural materials designed for and made of high- and ultra high-strength concrete under current domestic situation in Korea. In order to validate and assess the proposed elastic modulus equation, more than 400 laboratory test data available in the domestic literature on compressive strength of concrete in the range between 400 to 1,000 $kgf/cm^2$ were used and analyzed statistically. Comparison analyses of the proposed elastic modulus equation with previously suggested equations of ACI363R, CEB-FIP, NS3473 and New-RC are also presented to demonstrate its applicability in domestic practice.

Prediction of Elastic Modulus of High-Strength Concrete (고강도 콘크리트의 탄성계수 추정에 관한 연구)

  • 장일영;박훈규;이승훈;김규동;손유신
    • Proceedings of the Korea Concrete Institute Conference
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    • 2001.05a
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    • pp.37-42
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    • 2001
  • This paper presents the improved elastic modulus equation more appropriate to predict the modulus of elasticity of structural elements designed and made by high-strength concrete. To propose the elastic modulus equation, more than 300 laboratory specimen tests having the range of 5n to 800kgf/$cm^{2}$ in concrete compressive strength were conducted and analyzed statistically. The equation derived in terms of empirical constant, the elastic moduli of coarse aggregate and mix proportions. Comparison of the proposed elastic modulus equation with the previously suggested equations in the ACI363R, and New-RC were also presented to demonstrate the applicability to practice.

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Determination of Elastic Modulus by Time Average ESPI and Euler-Bernoulli Equation (Time Average ESPI와 Euler-Bernoulli 방정식에 의한 탄성계수 측정)

  • Kim, Koung-Suk;Lee, Hang-Seo;Kang, Young-June;Kang, Ki-Soo
    • Journal of the Korean Society for Precision Engineering
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    • v.24 no.7 s.196
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    • pp.69-74
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    • 2007
  • The paper proposes a new sonic resonance test for a elastic modulus measurement which is based on time-average electronic speckle pattern interferometry(TA-ESPI) and Euler-Bernoulli equation. Previous measurement technique of elastic constant has the limitation of application for thin film or polymer material because contact to specimen affects the result. TA-ESPI has been developed as a non-contact optical measurement technique which can visualize resonance vibration mode shapes with whole-field. The maximum vibration amplitude at each vibration mode shape is a clue to find the resonance frequencies. The dynamic elastic constant of test material can be easily estimated from Euler-Bernoulli equation using the measured resonance frequencies. The proposed technique is able to give high accurate elastic modulus of materials through a simple experiment set up and analysis.

Presumption of Optimum Concrete Elastic Modulus according to Content of Crushed Stone Powder (폐석분 함유율에 따른 최적의 콘크리트 탄성계수 추정)

  • Park Do-Kyong;Yang Keek-Young
    • Journal of the Korea Institute of Building Construction
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    • v.6 no.1 s.19
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    • pp.101-107
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    • 2006
  • While a Study with regard to the measurement on Concrete Strength and the Change of Drying Shrinkage in accordace with Content Ratio of Crushed Stone Powder, it is being analyzed as the result that the strength according to Content Ratio of crushed Stone Powder is somewhat lowering. Accordingly, it is the real situation that the Concrete mixed with Crushed Stone Powder is utilized for non-structural material, not for the structural material. Therefore, this Research willing to furnish the suitable utilizing scheme for construction site as well as practical life by means of conduct the experiment on both Concrete Pressure Strength according to mixture with Crushed Stone Powder and Elastic Modulus, it also presumes the optimum Elastic Modulus Equation after analysis of comparison with common concrete strength. As the result of the experiment, in case of the Content Ratio of Crushed Stone Powder is less than 5%, it did not display a big difference in its both strength and matter-property compare with common concrete. In case of Elastic Modulus, when the Pressure Strength is 50% and 40% respectively, the Elastic Modulus Equation accords very well with the provided condition of Quadratic function, and as the result of the Presumption on Elastic Modulus according to Content of Crushed Stone Powder, in case the Pressure Strength is 50%, Elastic Modulus Equation showed that Error Ratio of Cubic function is at degree of 0.0005%, in case the Pressure Strength is 40%, Elastic Modulus Equation was accorded well with the value of the experimental data likely as the Error Ratio of Cubic function is at the degree around 0.0034%, respectively.

A Proposal of Elastic Modulus Equation for High-Strength and Ultra-High-Strength Concrete (국내 실정에 적합한 고강도 및 초고강도 콘크리트의 탄성계수식 제안)

  • 장일영;송재호;박훈규;윤영수
    • Proceedings of the Korea Concrete Institute Conference
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    • 1996.10a
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    • pp.245-250
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    • 1996
  • The aim of this study is to suggest the new elastic modulus equation that suits to a domestic situation to coincide the improved mechanical properties of high-strength concrete and ultra-high-strength concrete. For thish purpose, this study collected the laboratory data more than 400 connceted with the the modulus of elasticity that performed in this country and also analyzed it statistically. The compressive strength of investigated concrete ranged from 400 to 1,400kg/$\textrm{cm}^2$. As a result, a practical and useful elastic modulus equation is proposed, it can be considered as most suitable equation in domestic situation.

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A Proposal of Elastic Modulus Equation for High-Strength and Ultra-High-Strength Concrete (국내의 실험자료를 이용한 고강도 및 초고강도 콘크리트의 탄성계수식 제안)

  • 장일영;박훈규;윤영수
    • Magazine of the Korea Concrete Institute
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    • v.8 no.6
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    • pp.213-222
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    • 1996
  • This paper presents the improved elastic modulus equation more appropriate to predict the modulus of elasticity of structural elements designed and made by high- and ultra high-strength concrete under domestic situation in Korea. To justify and assess the proposed elastic modulus equation, more than 400 laboratory test data domestically available in the literature and having the range of 400 to 1.000kg/$\textrm{cm}^2$ in concrete compressive strength were collected and analyzed statistically. Comparison of the proposed elastic modulus equation with the previously suggested equations in the ACI363R. CEB-FIP, NS3473 and New-RC were also presented to demonstrate the applicability to practice.

Evaluation of Young's Modulus of a Cantilever Beam by TA-ESPI (TA-ESPI에 의한 외팔보의 탄성계수 측정)

  • Lee H.S.;Kim K.S.;Kang K.S.;Jung H.C.;Yang S.P.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2005.06a
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    • pp.1115-1119
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    • 2005
  • The paper proposes the elastic modulus evaluation technique of a cantilever beam by vibration analysis based on time-average electronic speckle pattern interferometry (TA-ESPI) with non-contact and nondestructive and Euler-Bernoulli equation. General approaches for the measurement of elastic modulus of thin film are Nano indentation test, Bulge test and Micro-tensile test and so on. They each have strength and weakness in the preparation of test specimen and the analysis of experimental result. ESPI has been developed as a common measurement method for vibration mode visualization and surface displacement. Whole-field vibration mode shape (surface displacement distribution) at a resonance frequency can be visualized by ESPI. And the maximum surface displacement distribution from ESPI is a clue to find the resonance frequency at each vibration mode shape. And the elastic modules of test material can be easily estimated from the measured resonance frequency and Euler-Bernoulli equation. The TA-ESPI vibration analysis technique is able to give the elastic modulus of materials through the simple processing of preparation and analysis.

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Prediction of Elastic Modulus of Unidirectional Short Fiber Composite Materials (일방향으로 배열된 단섬유 보강 복합재료의 탄성률 예측)

  • 임태원;권영두;한경섭
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.14 no.2
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    • pp.407-412
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    • 1990
  • Elastic modulus of unidirectional short fiber composite has theoretically derived with the consideration of Poisson's ratios of matrix and fiber. Unidirectional short fiber composite is modeled as an aggregate of grains developed by Kerner. Under the assumption of extra strain at fiber ends, the strain distribution along the fiber's length is determined, and the elastic modulus is derived from this distribution. For the consideration of effects of Poisson's ratio, Kerner's results for particulate composites are adapted as boundary conditions. The effect of differences in Poisson's ratio of fiber and matrix on elastic modulus is studied. Proposed equation shows a good agreement with experimental data of Halpin and Tock, et al.

Measurement of Dynamic Elastic Modulus of Foil Material by ESPI and Sonic Resonance Testing (ESPI와 음향공진법을 이용한 Foil 재료의 동적탄성계수 측정)

  • Lee H.S.;Kim K.S.;Kang K.S.;Ahmad Akhlaq
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2005.10a
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    • pp.914-917
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    • 2005
  • The paper proposes a new sonic resonance test for a dynamic elastic constant measurement which is based on time-average electronic speckle pattern interferometry(TA-ESPI)and Euler-Bernoulli equation. Previous measurement technique of dynamic elastic constant has the limitation of application for thin film or polymer material because contact to specimen affects the result. TA-ESPI has been developed as a non-contact optical measurement technique which can visualize resonance vibration mode shapes with whole-field. The maximum vibration amplitude at each vibration mode shape is a clue to find the resonance frequencies. The dynamic elastic constant of test material can be easily estimated from Euler-Bernoulli equation using the measured resonance frequencies. The TA-ESPI dynamic elastic constant measurement technique is able to give high accurate elastic modulus of materials through a simple experiment and analysis.

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