• Title, Summary, Keyword: Tensile properties

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Tensile Creep Properties of Concrete under Restrained Shrinkage (구속수축에 의한 콘크리트 인장크리프 특성)

  • Choi, Hoon-Jae;Seo, Tae-Seok
    • Proceedings of the Korean Institute of Building Construction Conference
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    • pp.28-29
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    • 2016
  • By Testing restrained shrinkage, it is possible to estimating the cracking tendency of concrete such as time to cracking, tensile stress and tensile creep. In this study, tensile creep properties of concrete under restraint shrinkage were investigation through comparison of specimens that JIS and AASHTO proposed. As a results, tensile creep strains in concrete ring specimens were 15% higher than those in uniaxial specimens.

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Measurement of Tensile Properties of Copper Foil using Micro-ESPI Technique (마이크로 ESPI기법을 이용한 동 박막의 인장 특성 측정)

  • 김동일;허용학;기창두
    • Journal of the Korean Society for Precision Engineering
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    • v.21 no.8
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    • pp.89-96
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    • 2004
  • Micro-tensile testing system, consisting of a micro tensile loading system and micro-ESPI(Electronic Speckle Pattern Interferometry) system, has been developed for measurement of micro-tensile properties of thin micro-materials. Micro-tensile loading system had a load cell with the maximum capacity of 50N and micro actuator with resolution of 4.5nm in stroke. The system was used to apply a tensile load to the micro-sized specimen. During tensile loading, the micro-ESPI system acquired interferornetric speckle patterns in the deformed specimen and measured the in-plane tensile strain. The ESPI system consisted of a CCD-camera with a lens and the window-based program developed for this experiment. Using this system, stress-strain curves for 4 kinds of electrolytic copper foil 18$\square$m thick were obtained. From these curves, tensile properties, including the elastic modulus. yielding strength and tensile strength, were determined and also values of the plastic exponent and coefficient based on Ramberg-Osgood relationship were evaluated.

Evaluation of Micro-Tensile Properties for Nano-coating Material TiN (나노 코팅재 TiN 의 마이크로 인장 특성 평가)

  • Huh, Yong-Hak;Kim, Dong-Iel;Hahn, Jun-Hee;Kim, Gwang-Seok;Yeon, Soon-Chang;Kim, Yong-Hyub
    • Proceedings of the KSME Conference
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    • pp.240-245
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    • 2004
  • Tensile properties of hard coating material, TiN, were evaluated using micro-tensile testing system. TiN has been known as a hard coating material commonly used today. Micro-tensile testing system consisted of a micro tensile loading system and a micro-ESPI(Electronic Speckle Pattern Interferometry) system. Micro-tensile loading system had a maximum load capacity of 500mN and a resolution of 4.5 nm in stroke. TiN thin film $1{\mu}m$ thick was deposited on the Si wafer pre-deposited of $Si_3N_4$ film substrate by the closed field unbalanced magnetron sputtering (CFUBMS) process. Three kinds of micro-tensile specimen with the respective width of $50{\mu}m$, $100{\mu}m$ and $500{\mu}m$ were fabricated by MEMS process. The mechanical properties including tensile strength and elastic modulus were determined using the micro-tensile testing system and compared by those obtained by nano-indentation

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Effect of Water Absorption on the Tensile Properties of Carbon-Glass/Epoxy Hybrid Composite in Low Temperature (탄소-유리/에폭시 하이브리드 복합재의 저온 인장 특성에 미치는 수분의 영향)

  • Jung, Hana;Kim, Yonjig
    • Korean Journal of Metals and Materials
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    • v.50 no.10
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    • pp.729-734
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    • 2012
  • This study investigated the effect of water absorption on the tensile properties of carbon-glass/epoxy hybrid composites at room temperature and $-30^{\circ}C$. To investigate the effect of the position of glass fabric in the hybrid composite on the tensile properties, the stacking pattern of the fiber fabrics for reinforcing was created in three different ways: (a) glass fabrics sandwiched between carbon fabrics, (b) carbon fabrics sandwiched between glass fabrics and (c) alternative layers of carbon and glass fabrics. They were manufactured by a vacuum-assisted resin transfer molding (VARTM) process. The results showed that there was surprisingly little difference in tensile strength at the two different temperatures with dry and wet conditions. However, the water absorption into the hybrid system affected the tensile properties of the hybrid composites at RT and $-30^{\circ}C$. When the glass fabrics were at the outermost layers, the hybrid composite had the lowest tensile properties. This is attributed to the fact that the composite had a relatively high water absorption rate.

Measurement of mechanical properties of SU-8 thin film by tensile testing (단축 인장에 의한 SU-8박막의 기계적 물성 측정)

  • 백동천;박태상;이순복;이낙규
    • Journal of the Semiconductor & Display Technology
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    • v.3 no.2
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    • pp.23-26
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    • 2004
  • Thin film is one of the most general structures used in micro-electro-mechanical systems (MEMS). To measure the mechanical properties of SU-8 film, tensile testing was adopted which offers not only elastic modulus but also yield strength and plastic deformation by load-displacement curve. Tensile testing system was constructed with linear guided servo motor for actuation, load cell for force measurement and dual microscope for strain measurement.

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A Novel Tensile Specimen and Tensile Tester for Mechanical Properties of Thin Films (박막의 기계적 물성을 위한 새로운 인장 시편 및 인장 시험기)

  • Park, Jun-Hyub;Kim, Yun-Jae
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.31 no.6
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    • pp.644-650
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    • 2007
  • Mechanical property evaluation of micrometer-sized structures is necessary to help design reliable microelectromechanical systems(MEMS) devices. Most material properties are known to exhibit dependence on specimen size and such properties of microscale structures are not well characterized. This paper describes techniques developed for tensile testing of thin film used in MEMS. Epi-polycrystalline silicon is currently the most widely used material, and its tensile strength has been measured as 1.52GPa. We have developed a tensile testing machine for testing microscale specimen using electro-magnetic actuator. The field magnet and the moving coil taken from an audio-speaker were utilized as the components of the actuator. Structure of specimen was designed and manufactured for easy handling and alignment. In addition to the static tensile tests, it is described that new techniques and procedures can be adopted for high cycle fatigue test of a thin film.

Relationship between RVA Properties and Film Physical Properties of Native Corn Starch and Hydroxypropylated Corn Starch (천연옥수수전분과 hydroxypropyl화 옥수수전분의 RVA특성과 필름 물성의 관계)

  • Han, Youn-Jeong;Kim, Suk-Shin
    • Korean Journal of Food Science and Technology
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    • v.34 no.6
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    • pp.1023-1029
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    • 2002
  • Relationship between RVA properties and physical properties of film made from native corn starch and hydroxypropylated corn starch at various levels of plasticizers was examinel. Tensile strength of the film decreased, but its elongation and water vapor permeability increased with increasing plasticizer concentration. The film with glycerol showed greater changes in physical properties than that with sorbitol. Hydroxypropylated starch film showed lower tensile strength, higher elongation, and higher water vapor permeability than the native starch film. Sorbitol resulted in films with relatively high tensile strength, whereas glycerol produced films with increased elongation. The most reliable parameters for the relationship between RVA properties and film properties were RVA peak viscosity, tensile strength, and water vapor permeability. Water vapor permeability and tensile strength had linear relationship with RVA properties. The tensile strength and water vapor permeability of film could be predicted using the RVA peak viscosity.

Analysis of Notched Bar Tensile Tests for Inconel 617 at Room and Elevated Temperatures (Inconel 617 노치시편의 상온 및 고온 인장실험 해석)

  • Oh, Chang-Sik;Ma, Young-Wha;Yoon, Kee-Bong;Kim, Yun-Jae
    • Proceedings of the KSME Conference
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    • pp.1818-1823
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    • 2007
  • In this paper, notched bar tensile tests of Inconel 617 were performed at room ($20^{\circ}C$) and elevated ($800^{\circ}C$) temperature. Finite element analyses are also performed. It is found that, at the room temperature, smooth bar tensile test results could be used to simulate notched bar tensile tests. However, at the elevated temperature, notched bar tensile test results can not be simulated from smooth bar tensile test results. Metallurgical examination reveals that strength weakening results from many cavities over the specimens for smooth bar test at the elevated temperature. "True" tensile properties at the elevated temperature is found using FE simulations. It also suggests that cautious should be taken to determine tensile properties of Inconel 617 at elevated temperatures using smooth bar tests.

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Measurement of Tensile Properties Dependent on the Small-Scaled Specimen Dimension for Evaluation of In-Service Materials Properties (사용재 물성 평가를 위한 미소 시험편 크기에 따른 인장 특성 평가)

  • Huh, Yong-Hak;Kim, Dong-Iei;Kim, Dong-Jin;Lee, Hae-Moo;Park, Jong-Seo
    • Journal of the Korean Society of Safety
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    • v.23 no.5
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    • pp.30-34
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    • 2008
  • To evaluate the mechanical properties of in-service materials, tensile properties measurement using small-scaled specimen has been carried out. Tensile testing specimens with various dimensions, including standard and sub-size specimen specified in ASTM and ISO and small-scaled specimen, were prepared. Tensile strain in small-scaled specimen was measured using micro-ESPI system set up in this study. This system was used in the specimen with the parallel length of 2 mm and in subsequently measuring the strain under tensile loading. From each type of tensile specimen, stress-strain curves were determined. The dimension effect of the tensile properties was investigated comparing the tensile results obtained from standard specimens and small-scaled specimens. It was shown that the tensile strength for the small-scaled specimen is lower by 15% than those for the standard specimen.

Tensile strength of unidirectional CFRP laminate under high strain rate

  • Taniguchi, Norihiko;Nishiwaki, Tsuyoshi;Kawada, Hiroyuki
    • Advanced Composite Materials
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    • v.16 no.2
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    • pp.167-180
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    • 2007
  • The tensile strength of unidirectional carbon fiber reinforced plastics under a high strain rate was experimentally investigated. A high-strain-rate test was performed using the tension-type split Hopkinson bar technique. In order to obtain the tensile stress-strain relations, a special fixture was used for the impact tensile specimen. The experimental results demonstrated that the tensile modulus and strength in the longitudinal direction are independent of the strain rate. In contrast, the tensile properties in the transverse direction and the shear properties increase with the strain rate. Moreover, it was observed that the strain-rate dependence of the shear strength is much stronger than that of the transverse strength. The tensile strength of off-axis specimens was measured using an oblique tab, and the experimental results were compared with the tensile strength predicted based on the Tsai-Hill failure criterion. It was concluded that the tensile strength can be characterized quite well using the above failure criterion under dynamic loading conditions.