• Title/Summary/Keyword: Parallel Finite Element Analysis

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Analysis on Inhomogeneous Textures Developed in Aluminum AA 1050 Sheets during Continuous Confined Strip Shearing (알루미늄 AA 1050 판재구속전단가공 시 불균질 집합조직 형성의 해석)

  • 이재필;석한길;허무영
    • Transactions of Materials Processing
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    • v.13 no.4
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    • pp.382-387
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    • 2004
  • The continuous confined strip shearing (CCSS) based on the equal channel angular pressing (ECAP) was modeled by means of a rigid-plastic two-dimensional finite element method (FEM). Parallel to the simulations, samples of AA 1050 sheets were experimentally deformed by CCSS. The CCSS deformation led to the formation of through thickness texture gradients comprising a strong shear texture in the sheet center and weak shear textures in the sheet surfaces. FEM analysis revealed variations in the strain component $\varepsilon_13$ along the sample thickness direction, which gave rise to the evolution of different textures. A high friction between the sample and die surface was responsible for lowering intensities of the shear texture components in thickness layers close to the surfaces.

Fabrication and Characterization of Thermally Actuated Bimorph Probe for Living Cell Measurements with Experimental and Numerical Analysis

  • Cho Young-Hak;Kang Beom-Joon;Hong Seok-Kwan;Kang Jeong-Jin
    • Journal of Mechanical Science and Technology
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    • v.20 no.3
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    • pp.297-309
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    • 2006
  • This paper deals with a novel structure for single-cell characterization which makes use of bimorph micro thermal actuators combined with electrical sensor device and integrated microfluidic channel. The goal for this device is to capture and characterize individual biocell. Quantitative and qualitative characteristics of bimorph thermal actuator were analyzed with finite element analysis methods. Furthermore, optimization for the dimension of cantilevers and integrated parallel probe systems with microfluidic channels is able to be realized through the virtual simulation for actuation and the practical fabrication of prototype of probes. The experimental value of probe deflection was in accordance with the simulated one.

Analysis on Slotless BLDC Motors according to Magnetization pattern (슬롯리스형 BLDC 전동기의 자화패턴에 따른 특성 해석)

  • Jang Seok-Myeong;Park Ji-hoon;Choi Jang-Young;Ryu Dong-Wan
    • Proceedings of the KIEE Conference
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    • summer
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    • pp.1070-1072
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    • 2004
  • In this paper, the characteristic of slotless permanent magnet brushless motors analyze and compare parallel with radial way. This paper derive magnetic field solutions due to the PM. Torque, flux linkage and back emf are then derived. The results are shown in good conformity with those obtained from the commonly used finite element analysis.

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Rotor Loss Analysis of Permanent Magnet High-Speed Machine According to Magnetization Pattern

  • Cho, Han-Wook;Jang, Seok-Myeong;Lee, Sung-Ho;Yang, Hyun-Sup;Jeong, Yeon-Ho
    • KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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    • v.4B no.3
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    • pp.103-107
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    • 2004
  • Recently, greater attention has been paid to the high-speed generator for its many merits, such as ease of installation, high efficiency and high power density. However, due to their high fundamental frequency, careful consideration needs to be given to both electromagnetic and mechanical design issues. This paper deals with the comparison of two types of permanent magnet high-speed machines. Specifically, the effect of the permanent magnet magnetization pattern on the rotor losses is investigated. On the basis of analytical field analysis and the 2-D finite element method, this paper predicts the flux harmonics and rotor losses under the no-load condition. It is shown that the Halbach magnetization is superior to parallel magnetization in terms of producing rotor losses.

Large-scale Simulation for Optimal Design of Composite Curved Piezoelectric Actuator (복합재료 곡면형 자동기의 최적설계를 위한 대규모 수치해석 연구)

  • Chung, Soon-Wan;Hwang, In-Seong;Kim, Seung-Jo
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 2005.04a
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    • pp.5-8
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    • 2005
  • In this paper, the electromechanical displacements of curved piezoelectric actuators composed of PZT ceramic and laminated composite materials are calculated based on high performance computing technology and the optimal configuration of composite curved actuator is examined. To accurately predict the local pre-stress in the device due to the mismatch in coefficients of thermal expansion, carbon-epoxy and glass-epoxy as well as PZT ceramic are numerically modeled by using hexahedral solid elements. Because the modeling of these thin layers increases the number of degrees of freedom, large-scale structural analyses are performed through the PEGASUS supercomputer, which is installed in our laboratory. In the first stage, the curved shape of the actuator and the internal stress in each layer are obtained by the cured curvature analysis. Subsequently, the displacement due to the piezoelectric force (which is resulted from applied voltage) is also calculated. The performance of composite curved actuator is investigated by comparing the displacements obtained by the variation of thickness and elastic modulus of laminated composite layers. In order to consider the finite deformation in the first analysis stage and include the pre-stress due to curing process in the second stage, nonlinear finite element analyses are carried out.

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Fast Evaluation of Sound Radiation by Vibrating Structures with ACIRAN/AR

  • Migeot, Jean-Louis;Lielens, Gregory;Coyette, Jean-Pierre
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2008.11a
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    • pp.561-562
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    • 2008
  • The numerical analysis of sound radiation by vibrating structure is a well known and mature technology used in many industries. Accurate methods based on the boundary or finite element method have been successfully developed over the last two decades and are now available in standard CAE tools. These methods are however known to require significant computational resources which, furthermore, very quickly increase with the frequency of interest. The low speed of most current methods is a main obstacle for a systematic use of acoustic CAE in industrial design processes. In this paper we are going to present a set of innovative techniques that significantly speed-up the calculation of acoustic radiation indicators (acoustic pressure, velocity, intensity and power; contribution vectors). The modeling is based on the well known combination of finite elements and infinite elements but also combines the following ingredients to obtain a very high performance: o a multi-frontal massively parallel sparse direct solver; o a multi-frequency solver based on the Krylov method; o the use of pellicular acoustic modes as a vector basis for representing acoustic excitations; o the numerical evaluation of Green functions related to the specific geometry of the problem under investigation. All these ingredients are embedded in the ACTRAN/AR CAE tool which provides unprecedented performance for acoustic radiation analysis. The method will be demonstrated on several applications taken from various industries.

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Nonlinear Finite Element Analysis of Reinforced Concrete Columns (철근콘크리트 기둥의 3차원 비선형 유한요소 해석)

  • Kwon Minho;Chang Chun Ho
    • Journal of the Korea Concrete Institute
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    • v.16 no.3 s.81
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    • pp.397-406
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    • 2004
  • A recently developed three dimensional concrete law is used for the analysis of concrete specimens and reinforced concrete columns subjected to different load patterns. The hypoelastic, orthotropic concrete constitutive model includes coupling between the deviatoric and volumetric stresses, works with both proportional and non-proportional loads and is implemented as a strain driven module. The FE implementation is based on the smeared crack approach with rotating cracks parallel to the principal strain directions. The concrete model is validated through correlated studies with: (a) experimental tests on confined concrete cylinders; (b) experimental results on three reinforced concrete columns tested at the University of California, San Diego. The correlations are overall very good, and the FE responses capture all the main phenomena observed in the experimental tests.

Dielectric Breakdown Analysis of Bone-Like Materials with Conductive Channels (전도채널을 갖는 뼈와 유사한 재료의 절연파괴 해석)

  • Lee, Bo-Hyun;Lin, Song;Beom, Hyeon-Gyu
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.35 no.6
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    • pp.583-589
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    • 2011
  • The dielectric breakdown of bone-like materials subject to purely electric fields is investigated. In general, these materials consist of some layers with stronger dielectric strength and others with weaker dielectric strength in a parallel staggered pattern. The growth of the conductive channel is impeded during penetration of the weaker layer in the bone-like material because the electric-field concentration is relieved. The electric-field distribution around the head of the tubular channel is obtained from finite element analysis. The dielectric strength of the bone-like material is evaluated using the J integral, and some parameters affecting the dielectric strength are determined. It is shown that the J-integral values are reduced with an increase in the breakdown area in the weaker layer. It is also found that the ratio of the permittivity of the weaker layer to that of the stronger layer can strongly affect the dielectric breakdown.

Behavior of tension lap spliced sustainable concrete flexural members

  • Al-Azzawi, Adel A.;Daud, Raid A.;Daud, Sultan A.
    • Advances in concrete construction
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    • v.9 no.1
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    • pp.83-92
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    • 2020
  • The use of spliced reinforcing bars in sustainable concrete members to manage inadequate bars length is a common practical issue which is may be due to some limitations. The lap splicing means two bars overlapped in parallel with specified length called the splice length in order to provide the required bond between the two bars. The bond between sustainable concrete and spliced steel bars is another important issue. The normal strength sustainable concrete specimens of sizes 1700×150×150 mm with tension reinforcement lap spliced were selected according to testing device length limitations. These members were designed to fail in flexure in order to investigate the lap spliced tension bars effect. The selected lap spliced tension bars were of 10 mm size with smooth and deformed surfaces in order to investigate the surface nature accompanied with the splice nature. The sustainable concrete mechanical properties and mix workability were also studied. This study reveals that the effect of number of spliced bars on the response of beams reinforced with smooth bars is found to be more obvious than deformed one. Finite element modeling in three dimensions was carried out for the tested beams using ABAQUS software. A parametric study is carried out using finite elements on considering the following parameters, concrete compressive strength, load type and opening in cross section (hollow section) for weight reduction purposes.The laboratory and numerical results show good agreements in terms of ultimate load and deflection with an average difference of 10% and 15% in ultimate load and deflection respectively.

Domain Decomposition Approach Applied for Two- and Three-dimensional Problems via Direct Solution Methodology

  • Kwak, Jun Young;Cho, Haeseong;Chun, Tae Young;Shin, SangJoon;Bauchau, Olivier A.
    • International Journal of Aeronautical and Space Sciences
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    • v.16 no.2
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    • pp.177-189
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    • 2015
  • This paper presents an all-direct domain decomposition approach for large-scale structural analysis. The proposed approach achieves computational robustness and efficiency by enforcing the compatibility of the displacement field across the sub-domain boundaries via local Lagrange multipliers and augmented Lagrangian formulation (ALF). The proposed domain decomposition approach was compared to the existing FETI approach in terms of the computational time and memory usage. The parallel implementation of the proposed algorithm was described in detail. Finally, a preliminary validation was attempted for the proposed approach, and the numerical results of two- and three-dimensional problems were compared to those obtained through a dual-primal FETI approach. The results indicate an improvement in the performance as a result of the implementing the proposed approach.