• Title/Summary/Keyword: Material thickness

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An Influence of the Frictional Condition on Material Flow in Forward/Backward Combined Extrusion Process (전/후방 복합 압출공정에서 마찰조건이 재료 유동에 미치는 영향)

  • Kim, M.T.;Noh, J.H.;Hwang, B.B.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2009.10a
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    • pp.433-436
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    • 2009
  • This study is concerned with an effect of frictional condition in a forward/backward combined extrusion process. Generally, the material flow of the billet is influenced by the corners of the die cavity, the ratio in reduction in area, and thickness ratio of backward can thickness to forward can thickness. In addition, the frictional condition in contact area between the billet and the punch/die also affect the material flow. This paper investigated the effect of frictional condition for variable friction factors. The FEM simulation has been carried out in order to examine the effect of frictional condition. Deformation patterns and flow characteristics were examined in terms of design parameters such as extruded length ratio etc. Die pressure exerted on the die-workpiece interface is calculated by the simulation results and analyzed for safe tooling. Therefore the numerical simulation works provide a combined extrusion process of stable cold forging process planning to avoid the severe damage on the tool.

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Electroluminescent Properties of Organic Light-emitting Diodes Depending on the Thickness of CuPc Hole-injection Layer (정공 주입층 CuPc 두께 변화에 따른 유기 발광 소자의 발광 특성)

  • Lee, Jung-Bok;Kim, Kyung-Hwan;Kim, Tae-Wan;Lee, Won-Jae
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.26 no.12
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    • pp.899-903
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    • 2013
  • We investigated the luminescence properties of $Alq_3$ in the device structure of ITO/CuPc/TPD/$Alq_3$/Al. The CuPc as a hole-injection material and TPD as hole-transport material. Emission properties were measured by varying a layer thickness of CuPc (0 nm to 50 nm), which is the hole-injection layer. As a result, it was found that the hole injection occurs smoothly when the layer thickness was 20 nm among the thicknesses from 0 nm to 50 nm.

A Study on the Frequency Characteristics of a Class IV Flextensional Transducer (Class IV Flextensional 트랜스듀서의 주파수 특성 변화에 관한 연구)

  • 강국진;노용래
    • The Journal of the Acoustical Society of Korea
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    • v.18 no.7
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    • pp.67-73
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    • 1999
  • We constructed a class Ⅳ Flextensional transducer, and analyzed the effects of the variation in its material properties and structure on the resonance frequency of the transducer. We used the FEM for the analysis. Major axis length, minor axis length, thickness and material properties of the shell turned out to have large effects, while volume of the insert material, material properties and thickness of the ceramic bar have little. Thickness of the nodal-plate has no effect on the resonance frequency. Results of the present work can be utilized to design Class W Flextensional transducers of various resonance frequency.

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Measurement of all the Elastic, Dielectric and Piezoelectric Properties of PMN-PT Single Crystals (공진법을 이용한 PMN-PT 단결정의 탄성, 유전, 압전상수 측정)

  • 이상한;이수성;노용래;이호용;한진호
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.17 no.1
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    • pp.31-38
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    • 2004
  • PMN-PT, a piezoelectric single crystal, has many useful applications such as sensors and actuators. In this paper, all the elastic, piezoelectric, and dielectric constants of the PMN-32%PT single crystals were measured by the resonance method. For the rhombohedral symmetry, a total of twelve independent material constants were measured such as six elastic compliance constants at constant electric field, two dielectric constants at constant stress, and four piezoelectric constants d. Seven sets of crystal samples of each different geometry were prepared for the measurement of length-thickness extensional, thickness extensional, radial, length extensional and thickness shear modes of vibration, respectively. In order to check the validity of the measurement, experimental impedance spectrum of the PMN-PT crystal was compared with numerical data spectrum calculated with the measured material constants. The good agreement between the two spectra confirmed validity of the results in this paper.

Analysis of functionally graded plates using a sinusoidal shear deformation theory

  • Hadji, Lazreg
    • Smart Structures and Systems
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    • v.19 no.4
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    • pp.441-448
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    • 2017
  • This paper uses the four-variable refined plate theory for the free vibration analysis of functionally graded material (FGM) rectangular plates. The plate properties are assumed to be varied through the thickness following a simple power law distribution in terms of volume fraction of material constituents. The theory presented is variationally consistent, does not require shear correction factor, and gives rise to transverse shear stress variation such that the transverse shear stresses vary parabolically across the thickness satisfying shear stress free surface conditions. Equations of motion are derived from the Hamilton's principle. The closed-form solutions of functionally graded plates are obtained using Navier solution. Numerical results of the refined plate theory are presented to show the effect of the material distribution, the aspect and side-to-thickness ratio on the fundamental frequencies. It can be concluded that the proposed theory is accurate and simple in solving the free vibration behavior of functionally graded plates.

A Study on Performance Improvement of Sound Absorbing Noise Barrier (흡음형 방음벽의 성능향상에 관한 연구)

  • 김현실;김재승;강현주;김봉기;김상렬
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2001.11b
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    • pp.849-854
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    • 2001
  • A study on performance of the sound absorbing noise barrier is presented. Noise barrier of sound absorbing type is composed of the front panel, sound absorbing material, and back panel. For allowing sound path, front panel is usually perforated. The performance of the noise barrier is governed by the opening ratio of the perforated panel, sound absorption coefficient of the sound absorbing material. In this study, the effects of the opening ratio, diameter of the hole, thickness of the sound absorbing material are investigated. It is found that the thickness of the sound absorbing material must be at least 50 mm to ensure the required minimum NRC value 0.70, and the opening ratio is greater than 0.2. It is shown that the thickness of the back panel is crucial in providing required STL (Sound Transmission Loss) value. The performance of the developed noise barrier is measured, where its sound absorbing coefficient and sound transmission loss satisfy the criteria.

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Topology optimization of variable thickness Reissner-Mindlin plate using multiple in-plane bi-directional functionally graded materials

  • Nam G. Luu;Thanh T. Banh;Dongkyu Lee
    • Steel and Composite Structures
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    • v.48 no.5
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    • pp.583-597
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    • 2023
  • This paper introduces a novel approach to multi-material topology optimization (MTO) targeting in-plane bi-directional functionally graded (IBFG) non-uniform thickness Reissner-Mindlin plates, employing an alternative active phase approach. The mathematical formulation integrates a first shear deformation theory (FSDT) to address compliance minimization as the objective function. Through an alternating active-phase algorithm in conjunction with the block Gauss-Seidel method, the study transforms a multi-phase topology optimization challenge with multi-volume fraction constraints into multiple binary phase sub-problems, each with a single volume fraction constraint. The investigation focuses on IBFG materials that incorporate adequate local bulk and shear moduli to enhance the precision of material interactions. Furthermore, the well-established mixed interpolation of tensorial components 4-node elements (MITC4) is harnessed to tackle shear-locking issues inherent in thin plate models. The study meticulously presents detailed mathematical formulations for IBFG plates in the MTO framework, underscored by numerous numerical examples demonstrating the method's efficiency and reliability.

Effect of Boundary Conditions on Failure Probability of Corrosion Pipeline (부식 배관의 경계조건이 파손확률에 미치는 영향)

  • 이억섭;편장식
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2002.05a
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    • pp.873-876
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    • 2002
  • This paper presents the effect of internal corrosion, external corrosion, material properties, operation condition, earthquake, traffic load and design thickness in pipeline on the failure prediction using a failure probability model. A nonlinear corrosion is used to represent the loss of pipe wall thickness with time. The effects of environmental, operational, and design random variables such as a pipe diameter, earthquake, fluid pressure, a corrosion rate, a material yield stress and a pipe thickness on the failure probability are systematically investigated using a failure probability model for the corrosion pipeline.

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Effects of electron reflection for the tungsten oxide film coated on shadow mask in CRT (CRT Shadow mask 위에 도포된 산화텅스텐 피막의 전자반사 효과)

  • 김상문;배준호
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1998.11a
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    • pp.129-132
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    • 1998
  • In this paper, we have studied the effect of electron reflection on shadow mask on which tungsten oxide film is coated and have studied the variation of beam mislanding with coating thickness in CRT. We found the method to be able to control coating thicknessed and optimum coating thickness of tungsten oxide film was 1∼2$\mu\textrm{m}$. Mislanding of electron beam was reduced about 20∼48% with increasing coating thickness in CRT

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Effect of Boundary Conditions on failure Probability of Corrosion Pipeline (부식 배관의 경계조건이 파손확률에 미치는 영향)

  • 이억섭;편장식
    • Proceedings of the Korean Reliability Society Conference
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    • 2002.06a
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    • pp.403-410
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    • 2002
  • This paper presents the effect of internal corrosion, external corrosion, material properties, operation condition, earthquake, traffic load and design thickness in pipeline on the failure prediction using a failure probability model. A nonlinear corrosion is used to represent the loss of pipe wall thickness with time. The effects of environmental, operational, and design random variables such as a pipe diameter, earthquake, fluid pressure, a corrosion rate, a material yield stress and a pipe thickness on the failure probability are systematically investigated using a failure probability model for the corrosion pipeline.

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