• Title/Summary/Keyword: solid elements

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Comparison of Damping Capacities in Mg-Al and Mg-Zn Solid Solutions (Mg-Al 및 Mg-Zn 고용체의 진동감쇠능 비교)

  • Joong-Hwan Jun
    • Journal of the Korean Society for Heat Treatment
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    • v.36 no.6
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    • pp.389-395
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    • 2023
  • Damping capacities of Mg-2.5%Al and Mg-2.5%Zn (in atomic) solid solutions were comparatively investigated in order to clarify the influence of solutionized Al and Zn elements on the damping characteristics of Mg. In this study, solid solutions with similar grain size were obtained by solution treatment at 678 K for different times (24 h for Mg-2.5%Al and 36 h for Mg-2.5%Zn), followed by water quenching at RT. The Mg-2.5%Al and Mg-2.5%Zn solid solutions showed similar damping capacities in the strain-amplitude independent region of 1 × 10-6 ~ 1 × 10-5 and in the strain-amplitude dependent region below 6 × 10-4, over which the Mg-2.5%Zn solid solution possessed better damping capacity than the Mg-2.5%Al solid solution. The damping tendencies depending on strain-amplitude for the two solid solutions were analyzed and discussed in terms of similar length between weak pinning points (solutes) and different solute/dislocation interaction forces in Granato-Lücke model.

Stabilization of pressure solutions in four-node quadrilateral elements

  • Lee, Sang-Ho;Kim, Sang-Hyo
    • Structural Engineering and Mechanics
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    • v.6 no.6
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    • pp.711-725
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    • 1998
  • Mixed finite element formulations for incompressible materials show pressure oscillations or pressure modes in four-node quadrilateral elements. The criterion for the stability in the pressure solution is the so-called Babu$\check{s}$ka-Brezzi stability condition, and the four-node elements based on mixed variational principles do not appear to satisfy this condition. In this study, a pressure continuity residual based on the pressure discontinuity at element edges proposed by Hughes and Franca is used to study the stabilization of pressure solutions in bilinear displacement-constant pressure four-node quadrilateral elements. Also, a solid mechanics problem is presented by which the stability of mixed elements can be studied. It is shown that the pressure solutions, although stable, are shown to exhibit sensitivity to the stabilization parameters.

Mold Filling Analysis and Post-deformation Analysis of Injection-molded Aspheric Lenses for a Mobile Phone Camera Module (휴대폰 카메라용 비구면렌즈의 성형해석 및 후변형해석)

  • Park, Keun;Eom, Hyeju;Ahn, Jong-Ho
    • Design & Manufacturing
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    • v.6 no.1
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    • pp.12-17
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    • 2012
  • In order to produce high-quality optical components, aspheric lenses have been widely applied in recent years. An aspheric lens consists of aspheric surfaces instead of spherical ones, which causes difficulty in the design process as well as the manufacturing procedure. Although injection molding is widely used to fabricate optical lenses owing to its high productivity, there remains lots of difficulty to determine appropriate mold design factors and injection molding parameters. In the injection molding fields, computer simulation has been effectively applied to analyze processes based on the shell analysis so far. Considering the geometry of optical lenses, a full-3d simulation based on solid elements has been reported as a reliable approach. The present work covers three-dimensional injection molding simulation and relevant deformation analysis of an injection molded plastic lens based on 3d solid elements. Numerical analyses have been applied to the injection molding processes of three aspheric lenses for an image sensing module of a mobile phone. The reliability of the proposed approach has been verified in comparison with the experimental results.

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A Study on Physico-chemical Properties of Dust-fall in Inchon (대기중 강하먼지의 물리화학적 특성분석 -인천지역을 중심으로-)

  • 성일화;민달기;김종규
    • Journal of Environmental Health Sciences
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    • v.22 no.2
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    • pp.83-89
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    • 1996
  • In order to evaluate the air quality, dry and wet deposition samples were collected by deposit containers during four months in Inchon area. The samples were analyzed for its solid composition and trace elements(Ca, Cd, Cu, Fe, Mn, Ni, Pb, Zn). The main results are summarized below 1. The amounts of dry and wet deposition in Inchon area were 1.06~3.14 ton/$km^2$/month, and affected by the rainfall and suspended yellow sand. 2. Through the analysis of solid balance, we found that 50% of total solids(TS) was fixed suspend ed solids(FSS), 25% was fixed dissolved solids(FDS), and each of volatile suspended solids(VSS) and volatile dissolved solids(VDS) accounted for 12.5%. 3. The amounts collected by sampler for trace elements were 938 ~ 2,765 $\mu g$ calcium/10days sampler, 0.2 ~ 90.4 $\mu g$ cadmium/10days/sampler, 26 ~ 298 $\mu g$ copper/10days/sampler, 928 ~ 3,939 $\mu g$ iron/10days/sampler, 50 ~ 202 $\mu g$ manganese/10days/sampler, 4 ~ 37 $\mu g$ nickel/10days/sampler, 52 ~ 406 $\mu g$ lead/10days/sampler, and 97 ~ 1,317 $\mu g$ zinc/10days/sampler, respectively. 4. Using the manganese analysis, it was found that 76.1% of TS was from soil.

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Numerical analysis of injection molding of aspheric lenses for a mobile phone camera module (휴대폰 카메라용 비구면렌즈 사출성형의 수치해석)

  • Park, Keun;Eom, Hye-Ju
    • 한국금형공학회:학술대회논문집
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    • 2008.06a
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    • pp.143-148
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    • 2008
  • In order to produce high-quality optical components, aspheric lenses have been widely applied in recent years. An aspheric lens consists of aspheric surfaces instead of spherical ones, which causes difficulty in the design process as well as the manufacturing procedure. Although injection molding is widely used to fabricate optical lenses owing to its high productivity, there remains lots of difficulty to determine appropriate mold design factors and injection molding parameters. In the injection molding fields, computer simulation has been effectively applied to analyze processes based on the shell analysis so far. Considering the geometry of optical lenses, a full-3d simulation based on solid elements has been reported as a reliable approach. The present work covers three-dimensional injection molding simulation and relevant deformation analysis of an injection molded plastic lens based on 3d solid elements. Numerical analyses have been applied to the injection molding processes of three aspheric lenses for an image sensing module of a mobile phone. The reliability of the proposed approach has been verified in comparison with the experimental results.

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Static and Natural Vibration Analyses of Bending Problems Using 5-Node Equivalent Element (5절점 상당요소에 의한 굽힘문제의 정적해석 및 자유진동해석)

  • Gwon, Young-Doo;Yun, Tae-Hyeok;Jeong, Seung-Kap;Park, Hyeon-Chul
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.20 no.4
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    • pp.1320-1332
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    • 1996
  • In the present study, we consider modified 5-node equivalent solid element which has smallest degree of freedom among 2-dimensional solid elements accounting bending deformation as well as extensional and shear deformations, We shall investigate static and dynamic characteristics of this element, which is very effective in thin beam, thick beam, large displacement problems, beam of variable thickness, and asymmetrically stepped beam, etc., as well as relatively simple problems of beam. The degree of freedom of this element is 10, which is smaller than 18 of 9-node element, 16 of 8-node elemtns, 12 of modified 6-node element and Q6 element. Therefore, this element is expected to broaden the effective range of application of the solid elements in the bending problems further.

Numerical Analysis for the Injection Molding of an Aspheric Lens for a Photo Pick-up Device (광픽업용 비구면 렌즈 사출성형 공정의 수치해석)

  • 박근;한철엽
    • Journal of the Korean Society for Precision Engineering
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    • v.21 no.11
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    • pp.163-170
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    • 2004
  • In order to produce high-quality optical components, aspheric lenses have been widely applied in recent years. An aspheric lens consists of aspheric surfaces instead of spherical ones, which causes difficulty in the design process as well as the manufacturing procedure. Although injection molding is widely used to fabricate optical lenses owing to its high productivity, there remains lots of difficulty to determine appropriate mold design factors and injection molding parameters. In the injection molding fields, computer simulation has been effectively applied to analyze processes based on the shell analysis so far. Considering the geometry of optical lenses, however, numerical analysis based on solid elements has been reported as more reliable approach than shell -based one. The present work covers three-dimensional injection molding simulation using MP1/Flow3D and relevant deformation analysis of an injection molded plastic lens based on solid elements. Numerical analysis has been applied to the injection molding processes of an aspheric lens for a photo pick-up device. The reliability of the proposed approach has been verified in comparison with the experiments.

Phase analysis of simulated nuclear fuel debris synthesized using UO2, Zr, and stainless steel and leaching behavior of the fission products and matrix elements

  • Ryutaro Tonna;Takayuki Sasaki;Yuji Kodama;Taishi Kobayashi;Daisuke Akiyama;Akira Kirishima;Nobuaki Sato;Yuta Kumagai;Ryoji Kusaka;Masayuki Watanabe
    • Nuclear Engineering and Technology
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    • v.55 no.4
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    • pp.1300-1309
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    • 2023
  • Simulated debris was synthesized using UO2, Zr, and stainless steel and a heat treatment method under inert or oxidizing conditions. The primary U solid phase of the debris synthesized at 1473 K under inert conditions was UO2, whereas a (U, Zr)O2 solid solution formed at 1873 K. Under oxidizing conditions, a mixture of U3O8 and (Fe, Cr)UO4 phases formed at 1473 K, whereas a (U, Zr)O2+x solid solution formed at 1873 K. The leaching behavior of the fission products from the simulated debris was evaluated using two methods: the irradiation method, for which fission products were produced via neutron irradiation, and the doping method, for which trace amounts of non-radioactive elements were doped into the debris. The dissolution behavior of U depended on the properties of the debris and aqueous solution for immersion. Cs, Sr, and Ba leached out regardless of the primary solid phases. The leaching of high-valence Eu and Ru ions was suppressed, possibly owing to their solid-solution reaction with or incorporation into the uranium compounds of the simulated debris.

FlexDesigner:Object-Oriented Non-manifold Modeling Kernel with Hierarchically Modularized Structure (FlexDesigner:계층적으로 모듈화된 주초의 객체 지향 방식 비다양체 모델링 커널)

  • 이강수;이건우
    • Korean Journal of Computational Design and Engineering
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    • v.2 no.4
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    • pp.222-236
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    • 1997
  • Conventional solid or surface modeling systems cannot represent both the complete solid model and the abstract model in a unified framework. Recently, non-manifold modeling systems are proposed to solve this problem. This paper describes FlexDesigner, an open kernel system for modeling non-manifold models. It summarizes the data structure for non-manifold models, system design methodology, system modularization, and the typical characteristics of each module in the system. A data structure based on partial-topological elements is adopted to represent the relationship among topological elements. It is efficient in the usage of memory and has topological completeness compared with other published data structures. It can handle many non-manifold situations such as isolate vertices, dangling edges, dangling faces, a mixed dimensional model, and a cellular model. FlexDesigner is modularized hierarchically and designed by the object-oriented methodology for reusability. FlexDesigner is developed using the C++ and OpenGL on both SGI workstation and IBM PC.

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Application of graded harmonic FE in the analysis of 2D-FGM axisymmetric structures

  • Karakas, Ali I.;Daloglu, Ayse T.
    • Structural Engineering and Mechanics
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    • v.55 no.3
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    • pp.473-494
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    • 2015
  • A graded harmonic finite element formulation based on three-dimensional elasticity theory is developed for the structural analysis of 2D functionally graded axisymmetric structures. The mechanical properties of the axisymmetric solid structures composed of two different metals and ceramics are assumed to vary in radial and axial directions according to power law variations as a function of the volume fractions of the constituents. The material properties of the graded element are calculated at the integration points. Effects of material distribution profile on the static deformation, natural frequency and dynamic response analyses of particular axisymmetric solid structures are investigated by changing the power law exponents. It is observed that the displacements, stresses and natural frequencies are severely affected by the variation of axial and radial power law exponents. Good accuracy is obtained with fewer elements in the present study since Fourier series expansion eliminates the need of finite element mesh in circumferential direction and continuous material property distribution within the elements improves accuracy without refining the mesh size in axial and radial directions.