• Title/Summary/Keyword: Structural Properties

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Influence of Weft's Cotton Count & Weave Construction on the Mechanical Properties & Hand of Cotton Woven Fabrics (위사번수와 조직이 면직물의 역학특성 및 태에 미치는 영향)

  • Bae, Jin-Hwa;Park, Jung-Whan;An, Seung-Kook
    • Fashion & Textile Research Journal
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    • v.7 no.5
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    • pp.553-559
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    • 2005
  • Hand characteristics related with structural properties of fabrics have something to do with mechanical properties of fabric. In this study, the mechanical properties and hand characteristics have been analyzed according to fabric structural parameters such as the weave structure and the linear density of weft of cotton fabric. Mechanical properties have been used by KES-FB system which measures hand characteristics and mechanical properties of fabric. Linear density of weft, tensile, bending, and shear properties are decreasing with increasing weft linear density, and there is no considerable effects on compression and surface properties. In case of formability with weft linear density, B/W, 2HG/G, 2HB/B, 2HB/W, $\sqrt[3]{B/W}$, $\sqrt{2HB/W}$, W/T except MMD/SMD, WC/T, and WC/W have been effected. There is a high correlation between the crimp, tightness, hand, formability and mechanical properties specially tensile linearity, bending, shear, and compression properties. The weft crimp influences the bending rigidity, shear properties, and the tightness which have effects on the tensile linearity, bending, shear, compression properties, hand, and formability.

Structural Properties of $Ba(Zn_{1/3}Ta_{2/3})O_3$[BZT] Ceramics with Sintering Temperature (소결온도에 따른 $Ba(Zn_{1/3}Ta_{2/3})O_3$[BZT] 세라믹스의 구조적 특성)

  • Lee, Sang-Chul;Kim, Ji-Hoon;Kim, Kang;Lee, Sung-Gap;Lee, Young-Hie
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2000.04b
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    • pp.76-79
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    • 2000
  • The $Ba(Zn_{1/3}Ta_{2/3})O_3$ ceramics were prepared by conventional mixed oxide method. The structural properties of the BZT ceramics with the sintering temperature were investigated by XRD, SEM. The BZT ceramics have a complex-perovskite structure. The BZT ceramics sintered at $1550^{\circ}C$ had a superstructure plane of BZT(100). Increasing the sintering temperature, the bulk density and ordering were increased. The bulk density of the BZT ceramics sintered at $1550^{\circ}C$ was $7.50[g/cm^3]$. Increasing the sintering temperature, the average grain size were increased and pore were decreased.

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Formation and Physical Properties of Yogurt

  • Lee, W.J.;Lucey, J.A.
    • Asian-Australasian Journal of Animal Sciences
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    • v.23 no.9
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    • pp.1127-1136
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    • 2010
  • Yogurt gels are a type of soft solid, and these networks are relatively dynamic systems that are prone to structural rearrangements. The physical properties of yogurt gels can be qualitatively explained using a model for casein interactions that emphasizes a balance between attractive (e.g., hydrophobic attractions, casein cross-links contributed by calcium phosphate nanoclusters and covalent disulfide cross-links between caseins and denatured whey proteins) and repulsive (e.g., electrostatic or charge repulsions, mostly negative at the start of fermentation) forces. Various methods are discussed to investigate the physical and structural attributes of yogurts. Various processing variables are discussed which influence the textural properties of yogurts, such as total solids content, heat treatment, and incubation temperatures. A better understanding of factors contributing to the physical and structural attributes may allow manufacturers to improve the quality of yogurt.

Study on sensitivity of modal parameters for suspension bridges

  • Liu, Chunhua;Wang, Ton-Lo;Qin, Quan
    • Structural Engineering and Mechanics
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    • v.8 no.5
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    • pp.453-464
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    • 1999
  • Safety monitoring systems of structures generally resort to detecting possible changes of dynamic system parameters. Sensitivity analysis of these dynamic system parameters may implement these techniques. Conventional structural eigenvalue problems are discussed in the scope of those systems with deterministic parameters. Large and flexible structures, such as suspension bridges, actually possess stochastic material properties and these random properties unavoidably affect the dynamic system parameters. The sensitivity matrix of structural modal parameters to basic design variables has been established in this paper. Moreover, second order statistics of natural frequencies due to the randomness of material properties have been discussed. It is concluded from numerical analysis of a modem suspension bridge that although the second order statistics of frequencies are small relatively to the change of basic design variables, such as density of mass and modulus of elasticity, the sensitivities of modal parameters to these variables at different locations change in magnitude.

Structural dynamics: Convergence properties in the presence of damage and applications to masonry structures

  • Nappi, Alfonso;Facchin, Giovanni;Marcuzzi, Claudio
    • Structural Engineering and Mechanics
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    • v.5 no.5
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    • pp.587-598
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    • 1997
  • A numerical model for masonry is proposed by following an internal variable approach originally developed in the field of elastic-plastic analysis. The general features of the theoretical framework are discussed by focussing on finite element models applicable to incremental elastic-plastic problems. An extremum property is derived and its implications in terms of convergence for convenient algorithms are briefly discussed, by including the case of softening materials and damage effects. Next, a numerical model is presented, which is suitable for masonry, can be developed according to the same internal variable formulation and enjoys similar properties. Some numerical results are presented and compared with the response of a masonry shear wall subjected to pseudodynamic tests.

Effect of Oxygen Contents in Thermal Annealed ZnO films on Structural and Optical Properties (열처리한 ZnO 박막 내의 산소 농도 변화에 따른 구조적, 광학적 특성 연구)

  • Lee, Ju-Young;Kim, Hong-Seung;Jung, Eun-Soo;Jang, Nak-Won
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.18 no.7
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    • pp.600-604
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    • 2005
  • We studied that structural and optical properties of ZnO films depend on oxygen contents. ZnO films were deposited on Si (111) substrates at room temperature by rf sputtering system and the thickness of films was 100 nm. The ZnO films were annealed in thermal furnace for 2 h at 800 and $900^{\circ}C$ in $H_2O,\;N_2$, and air ambient gases to control oxygen contents. We used AES, PL, XRD, AFM. As our result, crystal quality and luminescence improved until O/Zn is 1. However, when O/Zn ratio Is larger than 1, the structural and optical properties were getting worse.

A Study on the Fabrication and Structural Properties of BaTiO$_3$ Thin Film by RF Sputtering (RF Sputtering법에 의한 BaTiO$_3$ 박막의 제조 및 구조적 특성에 관한 연구)

  • 이문기;류기원;배선기;이영희
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1996.05a
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    • pp.193-197
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    • 1996
  • BaTiO$_3$films in pure Ar atmosphere were prepared by RF sputtering method at low substrate temperature(100$^{\circ}C$). The structural and crystallographic properties were studied with deposition conditions and annealing methodes. Deposition rates and structural properties of BaTiO$_3$ thin filles were investigated by the SEM and X-ray diffraction. The chemical composition of BaTiO$_3$ thin films grown on Si(100) wafer was studied by tole EDS and EPHA. The optimised Ar pressure and RF power were 8[mtorr] and 180[W], respectively. The thickness of BaTiO$_3$ thin films deposited at optimised conditions was ∼3400[${\AA}$], and the dielectric constant of the thin films heat-treated at 750[$^{\circ}C$] for 1[hr] was 259.

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Characterizing Small-scale Mechanical Behaviors of Heat-treated Materials with Nanoindentation Technique (나노압입시험법을 이용한 열처리 소재의 미소 변형 거동 평가)

  • Choi, In-Chul
    • Journal of the Korean Society for Heat Treatment
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    • v.33 no.2
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    • pp.72-79
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    • 2020
  • To improve the mechanical properties of most structural materials for industrial applications, the control of microstructure is essential by heat treatment process or plastic deformation process. Since the mechanical behavior of structural materials is significantly influenced by their microstructure, it is inevitably preceded to understand the relationship between microstructure and strengthening mechanisms of materials which can be easily changed by heat treatment. In this regard, the nanoindentation test is useful technique for analyzing the influence of the localized microstructural change on small-scale mechanical behavior of various structural materials. Here, the interesting studies performed on various heat-treated materials are reviewed with focus on micromechanical properties obtained by nanoindentation, which are reported in the available literature.

Analytical Study on the Prestress Losses of Prestressed Concrete Bridges (PSC 교량의 프리스트레스 손실에 관한 해석적 연구)

  • Kim, Woon-Hak;Ra, Jeong-Kyoun;Kim, Tae-Hoon;Shin, Hyun-Mock
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.7 no.1
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    • pp.131-138
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    • 2003
  • This paper presents an analytical prediction of the prestress losses of prestressed concrete bridges. In this study a numerical procedure and computer program is developed to analyze the behavior of prestressed concrete bridges considering the time-dependent properties of material. It accounts for the aging, creep and shrinkage of concrete and the stress relaxation of prestressed steel. The structural model uses two dimensional plane frame elements with three nodal degree of freedom and is analyzed based on the finite element method. Member cross section can consist of concrete, reinforcement and prestressing steel. Two different set of equations for the prediction of time-dependent material properties of concrete are presented, which are ACI, CEB-FIP. The proposed numerical method for the prestress losses of prestressed concrete bridges is verified by comparison with reliable experimental results.

Study on Thermal and Structural Properties of Epoxy/Elastomer Blend (에폭시/엘라스토머 블렌드의 열적 및 구조적 특성에 관한 연구)

  • Lee Kyoung-Yong;Lee Kwan-Woo;Choi Yong-Sung;Park Dae-Hee
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.53 no.11
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    • pp.556-560
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    • 2004
  • In this paper, thermal and structural properties of epoxy/elastomer blend were measured by DSC, TGA and FESEM. Specimens were made of dumbbell forms by the ratio of 5, 10, 15, and 20[phr] by changing elastomer content. The measuring temperature ranges of DSC were from -20[℃] to 150[℃] and heating rate was 4[℃/min]. And the measuring temperature ranges of TGA were from 0[℃] to 800[℃], and heating rate was 5[℃/min]. Also we observed structure of specimens through FESEM with magnification of 1000 times and voltage of 15[kV] by breaking quenched specimens. As experimental results, we could know that thermal and structural properties were improved according to decrease of elastomer content. Because it increased glass transition temperature, high temperature and structure of elastic epoxy.