• Title/Summary/Keyword: Mechanical property evaluation

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Electro-mechanical Property Evaluation of REBCO Coated Conductor Tape with Stainless Steel Substrate

  • Dedicatoria, M.J.;Shin, H.S.;Ha, H.S.;Oh, S.S.;Moon, S.H.
    • Progress in Superconductivity and Cryogenics
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    • v.12 no.4
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    • pp.20-23
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    • 2010
  • In this study, the electromechanical property of REBCO coated conductor (CC) tape adopting a stainless steel substrate has been investigated. Sample was subjected to uniaxial tension and measured its mechanical properties at RT and 77 K. $I_c-{\varepsilon}_t$ relations was also studied in which the strain and stress corresponding to the 95% $I_c$ retention and reversible strain limit were measured. In addition, these results were compared to the case of conventional REBCO CC tape adopting a Hastelloy substrate. As a result, by adopting a stainless steel substrate comparable strength and good electromechanical property to Hastelloy one could be achieved.

Evaluation of Stress-Strain Characteristics of Weldment in Natural Gas Pipeline Using Advanced Indentation System (Advanced Indentation System을 이용한 천연가스배관 용접열영향부의 응력-변형률 변화 특성 분석)

  • Jang, Jae-Il;Son, Dong-Il;Kwon, Dong-Il;Kim, Woo-Sik;Park, Joo-Seung
    • Proceedings of the KSME Conference
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    • 2001.06a
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    • pp.483-488
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    • 2001
  • Until now, the tensile properties of materials can be obtained just in accordance with conventional tensile testing methods which are described in several standards such as ASTM (American Society for Testing and Materials) standard and BS (British Standard). For some cases including on-service facility materials, however, the standard testing methods cannot be applicable due to the destructive testing procedure and specimen size requirement. Therefore, simple, non-destructive and advanced indentation technique was proposed. This test measures indentation load-depth curve during indentation and analyzes the mechanical properties related to deformation and fracture. In this paper, the research trend of non-destructive evaluation of tensile properties using AIS (advanced indentation system) and its application fields are reviewed and discussed.

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Study on Optical Properties of Lithium niobate using Chemical Mechanical Polishing (화학 기계적 연마에 의한 리튬 니오베이트의 광학 특성에 관한 연구)

  • Jeong, Suk-Hoon;Kim, Young-Jin;Lee, Hyun-Seop;Jeong, Hae-Do
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2008.06a
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    • pp.121-122
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    • 2008
  • Lithium Niobate (LN:LiNbO3) is a compound of niobium, lithium and oxygen. The characteristics of LN are piezoelectricity, ferroelectricity and photoelectricity, and which is widely used in surface acoustic wave (SAW). To manufacture LN device, the LN surface should be a smooth surface and defect-free because of optical property, but the LN material is processed difficult by traditional processes such as grinding and mechanical polishing (MP) because of its brittleness. To decrease defects, chemical mechanical polishing (CMP) was applied to the LN wafer. In this study, the suitable parameters scuh as pressure and relative velocity, were investigated for the LN CMP process. To improve roughness, the LN CMP was performed using the parameters that were the highest removal rate among process parameters. And, evaluation of optical property was performed by the optical reflectance and non-linear characteristic.

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Characterization of Microstructure and Mechanical Properties of Micro-alloyed Cold Forging Steel and Product (냉간단조용 비조질강 및 성형품의 미세조직과 기계적 특성분석)

  • Suh D.W.;Lee Y.S.;Kwon Y.N.;Lee J.H.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2004.05a
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    • pp.409-412
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    • 2004
  • Microstructures and mechanical properties of microalloyed cold forging steel and cold forged prototype automobile part are characterized. The work hardening according to the increase of plastic strain plays a major role in increasing the tensile strength of microalloyed cold forging steel during cold forming. On the other hand, inhomogeneous distribution of plastic strain causes variations in microstructure and mechanical properties. The relation between inhomogeneous distribution of plastic strain and variations in microstructure and mechanical properties is discussed. The variation of mechanical property in cold forged automobile part is analyzed using quantitative evaluation of plastic strain from finite element method.

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A Berkovich Indentation Technique Based on 3D FEA solutions for Material Property Evaluation (3차원 유한요소해에 기초한 Berkovich 압입 물성평가법)

  • Kim, Min-Soo;Hyun, Hong-Chul;Lee, Kyoung-Yoon;Lee, Hyung-Yil
    • Proceedings of the KSME Conference
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    • 2008.11a
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    • pp.1-6
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    • 2008
  • Due to the self-similarity of Berkovich and conical indenters, different materials may show the same loaddepth curve for single indentation. In this study, we first compare the load-depth characteristics of conical and Berkovich indenters via finite element method. We also analyze the variation of load-depth curves with angle of Berkovich indenter, indentation parameters, and material properties. With numerical regressions of obtained data, we then propose dual-Berkovich indentation formulae for material property evaluation. The proposed approach provides the values of elastic modulus, yield strength and strain-hardening exponent and corresponding stress-strain curve with an average error of less than 3%. The method is valid for any elastic indenters made of tungsten carbide and diamond for instance.

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Blending Effect on the Mechanical and Hand Properties of Wool/Acrylic Blend Knits

  • Park Myung-Ja
    • The International Journal of Costume Culture
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    • v.8 no.1
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    • pp.23-31
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    • 2005
  • Mechanical properties and hand evaluation of wool/acrylic(W/A) blend knits were conducted before and after repeated washing to get the optimum W/A blending ratio, which could help achieve the optimum mechanical and hand properties of the knits. The five test fabrics using the yarns with different W/A blending ratios($\%$), 100/0, 70/30, 50/50, 30/70, 0/100, were knitted. The fabrics were washed by a rotating drum type washing machine. Then, objective mechanical and hand properties were evaluated by KES-FB, Kawabata evalution system for fabric. The results are as follows: there was no change in the hand value of the knitted fabric with the W/A-blended yarn caused by the change in the blending ratio before washing. After washing, however, the increase of acrylic's blending rate caused the bending property to decrease proportionally, while the friction coefficient of the surface property increased. Furthermore, the study showed that W/A 50/50 possesses the most superior tensile property and shearing property, which could attain the optimum blending ratio. Similar results in hand value were derived in all the samples. After washing, however, the increase in acrylic's blending rate caused a proportional decrease in KOSHI and an increase in FUKURAMI. In addition, W/A 50/50 gained the biggest NUMERI value, again corresponding to the optimum blending ratio. Similar results in total hand value were derived in all the samples before washing. After washing, though, all the total hand values decreased, and, as the wool fabric's blending rate increased, the total hand values proportionally decreased further.

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The Mechanical Properties of Corrugated Cardboard using Equivalent Evaluation (등가 물성 평가를 이용한 골판지의 물성치)

  • Kwon, Kyung Young;Jung, Jong-Yun
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.37 no.1
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    • pp.157-164
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    • 2014
  • The usage of corrugated cardboard for packing material is increasing in these days because it is light and easy to manufacture packing boxes. However, the structure analysis of packing boxes, made of cardboard, is not well carried. The reason can be deduced that its mechanical properties for structure analysis are not well known. The cardboards are made different shapes with various types of raw materials that are paper-based compound. In addition, the cardboards are considered to be orthotropic material. This research finds mechanical properties of triple layered cardboard which is composed of outer liner and inner liner. The moduli of elasticity and of shear for liners are found from tension test and T-Peel test. The mechanical properties of the cardboard are calculated using the super position method and equivalent evaluation method.