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  • Title/Summary/Keyword: 3D-FEM

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Simplified 3D Finite Element Analysis of Linear Inductor Motor for Integrated Magnetic Suspension/Propulsion Applications (자기부상 및 추진 일체형 리니어 인덕터 모터의 간이형 3차원 유한요소해석)

  • Jeong, Sang-Sub;Jang, Seok-Myeong
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.49 no.6
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    • pp.371-379
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    • 2000
  • The 4-pole linear homopolar synchronous motor (LHSM), so called linear inductor motor, is composed of the figure-of-eight shaped 3-phase armature windings, DC field windings, and the segmented secondary with the transverse bar track. To reduce the calculation time, the simplified 3D finite element model with equivalent reluctance and/or permanent magnet is presented. To obtain a clear understanding, propriety and usefulness of the developed model, we compare with the results of simplified 3D FEA, general 3D FEA and test. Consequently, the results of simplified and 3D FEM analysis are nearly identical, but much larger than that of static test at d-axis armature excitation. Therefore the improved FEA model, such as full model with half slot, is needed for the precise analysis.

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A Compact Integrated RF Transceiver Module for 2.4 GHz Band Using LTCC Technology (LTCC 기술을 적용한 집적화된 2.4 GHz 대역 무선 송수신 모듈 구현)

  • Kim, Dong-Ho;Kim, Dong-Su;Ryu, Jong-In;Kim, Jun-Chul;Park, Chong-Dae;Park, Jong-Chul
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.22 no.2
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    • pp.154-161
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    • 2011
  • This paper presents a compact integrated transceiver module for 2.4 GHz band applications using Low Temperature Co-fired Ceramic(LTCC) technology. The implemented transceiver module is divided into an RF Front-End Module (FEM) part and a transceiver IC chip part. The RF FEM part except an SPDT switch and DC block capacitors is fully embedded in the LTCC substrate. The fabricated RF FEM has 8 pattern layers and it occupies less than 3.3mm×5.2mm×0.4mm. The measured results of the implemented RF FEM are in good agreement with the simulated results. The transceiver IC chip part consists of signal line, power line and transceiver IC for 2.4 GHz band communication system. The fabricated transceiver module has 9 layers including three inner grounds and it occupies less than 12mm×8.0mm×1.1mm. The implemented transceiver module provides an output power of 18.1 dBm and a sensitivity of -85 dBm.

Technology for the Detection of Corrosion Defects in Buried Pipes of Nuclear Power Plants with 3D FEM (3D 유한요소법을 이용한 원전 매설배관 부식결함 탐상기술 개발)

  • Kim, Jae-Won;Lim, Bu-Taek;Park, Heung-Bae;Chang, Hyun-Young
    • Corrosion Science and Technology
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    • v.17 no.6
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    • pp.292-300
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    • 2018
  • The modeling of 3D finite elements based on CAD data has been used to detect sites of corrosion defects in buried pipes. The results generated sophisticated profiles of electrolytic potential and vectors of current distributions on the earth surface. To identify the location of defects in buried pipes, the current distribution on the earth surface was projected to a plane of incidence that was identical to the pipe locations. The locations of minimum electrolytic potential value were found. The results show adequate match between the locations of real and expected defects based on modeling. In addition, the defect size can be calculated by integrating the current density curve. The results show that the defect sizes were 0.74m2 and 0.69m2, respectively. This technology may represent a breakthrough in the detection of indirect damage in various cases involving multiple defects in size and shape, complex/cross pipe systems, multiple anodes and stray current.

Foundation Types of Fixed Offshore Wind Turbine

  • Yun Jae Kim;Jin-wook Choe;Jinseok Lim;Sung Woong Choi
    • Journal of Ocean Engineering and Technology
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    • v.38 no.2
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    • pp.74-85
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    • 2024
  • Offshore wind turbines are supported by various foundations, each with its considerations in design and construction. Gravity, monopile, and suction bucket foundations encounter geotechnical issues, while jacket and tripod foundations face fatigue problems. Considering this, a gravity foundation based on a steel skirt was developed, and a monopile foundation was analyzed for Pile-Soil Interaction using the p-y curve and 3D finite element method (3D FEM). In addition, for suction bucket foundations, the effects of lateral and vertical loads were analyzed using 3D FEM and centrifuge tests. Fatigue analysis for jacket and tripod foundations was conducted using a hotspot stress approach. Some hybrid foundations and shape optimization techniques that change the shape to complement the problems of each foundation described above were assessed. Hybrid foundations could increase lateral resistance compared to existing foundations because of the combined appendages, and optimization techniques could reduce costs by maximizing the efficiency of the structure or by reducing costs and weight. This paper presents the characteristics and research directions of the foundation through various studies on the foundation. In addition, the optimal design method is presented by explaining the problems of the foundation and suggesting ways to supplement them.

Developing a framework to integrate convolution quadrature time-domain boundary element method and image-based finite element method for 2-D elastodynamics

  • Takahiro Saitoh;Satoshi Toyoda
    • Advances in Computational Design
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    • v.9 no.3
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    • pp.213-227
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    • 2024
  • In this study, a framework for coupling of the convolution quadrature time-domain boundary element method (CQBEM) and image-based finite element method (IMFEM) is presented for 2-D elastic wave propagation. This coupling method has three advantages: 1) the finite element modeling for heterogeneous areas can be performed without difficulties by using digital data for the analysis model, 2) wave propagation in an infinite domain can be calculated with high accuracy by using the CQBEM, and 3) a small time-step size can be used. In general, a small time-step size cannot be used in the classical time-domain boundary element method. However, the CQBEM used in this analysis can address a small time-step size. This makes it possible to couple the CQBEM and image-based FEM which require a small-time step size. In this study, the formulation and validation of the pro-posed method are described and confirmed by solving fundamental elastic wave scattering problems. As a numerical example, elastic wave scattering in inhomogeneous media is demonstrated using the proposed coupling method.

Dynamic Analysis of 3 Different Cross-Sectional Shapes of a Fill Dam using 3D FEM Analysis (3차원 유한요소해석에 의한 필 댐의 3가지 단면 형상을 고려한 지진해석)

  • Choi, Byoungil
    • Journal of the Korean GEO-environmental Society
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    • v.16 no.8
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    • pp.37-43
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    • 2015
  • Dam movements are identified in real-time with measuring instruments for dam maintenance. However, for dams that have aged, the measuring instruments that were installed during the dam construction are frequently malfunctioning or completely failing altogether. Precision safety diagnosis is being executed for dams that are national facilities Type 1. During the diagnosis, a safety assessment is conducted for the dam body. Normally, during the analysis of dam safety, the widest cross-section is selected and a two-dimensional numerical analysis is taken place for the cross-section. However, numerous researchers have recently looked into applying the 3-dimensional numerical analysis program developments to precisely analyze the structure of the dam, as well as the surrounding strata, and the lower dam strata. In this study, PLAXIS 3D, a geotechnical generic FEM analysis program, was used to conduct dam safety assessments for earthquakes. The following were compared and analyzed: considering the seismic properties of the dam body with all zoned structures reflected as one rock-fill zone together with the dam body, considering the dam body as the rock-fill zone and the core zone, and the numerical analysis results. Thus, the study was aimed to analyze the impact properties of seismic waves according to the different zones.

FEM Electrical Resistivity Modeling in Cylindrical Coordinates (원통 좌표계에서의 전기비저항 유한요소 모델링)

  • Choi Wonseok;Kim Jung-Ho;Park KwonGyu;Kim Hak-Soo;Suh Jung-Hee
    • Geophysics and Geophysical Exploration
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    • v.5 no.3
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    • pp.206-216
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    • 2002
  • The finite element method (FEM), a powerful numerical modeling tool for solving various engineering problems, is frequently applied to three-dimensional (3-D) modeling thanks to its capability of discretizing and simulating the shape of model with finite number of elements. Considering the accuracy of the solution and computing time in modeling of engineering problems, it is preferable to construct physical continuity and simplify mesh system. Although there exist systematic mesh generation systems for arbitrary shaped model, it is hard to model a simple cylinder in terms of 3-D coordinate system especially in the vicinity of the central axis. In this study I adopt cylindrical coordinate system for modeling the 3-D model space and define the origin of the coordinates with mathematically clear coordinate transformation. Since we can simulate the whole space with hexahedral elements, the cylindrical coordinate system is effective in handling the 3-D model structure. The 3-D do resistivity modeling scheme developed in this study provides basie principle for borehole-to-surface resistivity survey, which can be a useful tool for the application to environmental problem.

Analysis of Switched Reluctance Motor based on 3D Equivalent Magnetic Circuit Network Method of New Shape Element (새로운 요소를 이용한 SRM의 3차원 등가자기회로망 해석)

  • Kim, Wa-Sung;Chun, Yon-Do;Kim, Youn-Hyun;Lee, Ju;Kim, Suk-Tae;Lee, Chol-Jik
    • Proceedings of the KIEE Conference
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    • 2001.07b
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    • pp.570-573
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    • 2001
  • This paper presents the characteristics of Switched Reluctance Motor (SRM) based on 3D Equivalent Magnetic Circuit Network Method (3D EMCNM). 3D EMCNM supplements magnetic equivalent circuit by numerical technique using distributive magnetic circuit parameters. However in case of SRM the previous 3D EMCNM which uses fan shape element is not proper for analysis. This paper solved this problem by developing the trapezoid element and verified the validity of the suggested element by comparing the results of 3D EMCNM with 2D FEM.

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Optimization of cables size and prestressing force for a single pylon cable-stayed bridge with Jaya algorithm

  • ATMACA, Barbaros;DEDE, Tayfun;GRZYWINSKI, Maksym
    • Steel and Composite Structures
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    • v.34 no.6
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    • pp.853-862
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    • 2020
  • In recent years, due to the many advantages cable-stayed bridges have often constructed in medium and long span. These advantages can be listed as an aesthetically pleasing appearance, economic and easy construction, etc. The main structural elements of cable-stayed bridges are listed as deck, pylon, cables and foundation. Perhaps one of the most vital and expensive of these structural elements is stay-cables. Stay-cables ensure the allowable displacement and distribution of bending moments along the bridge deck with prestressing force. Therefore the optimum design of the stay-cables and prestressing force are very important in achieving the performance expected from the cable-stayed bridges. This paper aims to obtain the stay-cables size and prestressing force optimization of the cable-stayed bridge. For this purpose, single pylon and fan type cable configuration Manavgat Cable-Stayed Bridge was selected as an example. The three dimensional (3D) finite element model (FEM) of the bridge was created with SAP2000. Analysis of the 3D FEM of the bridge was conducted under the different combined effects of the self-weight of the structural element, prestressing force of stay-cable and live load. Stay-cable stress and deck displacement were taken into account as constraints for the optimization problem. To optimize this existing bridge a metaheuristic algorithm named Jaya was used in the optimization process. 3D FEM of the selected bridge was repeatedly analyzed by using Open Applicable Programming Interface (OAPI) properties of SAP2000. To carry out the optimization process the developed program which integrates the Jaya algorithm and the required codes for calling SAP2000 is coded in MATLAB. At the end of the study, the total weight of the stay-cables was reduced more than 40% according to existing stay cables under loads taken into account.

A Study on Stress Concentration Factor of Composite Laminate Mechanical Joints (복합재료 적층판 기계적 체결부 응력집중계수에 대한 고찰)

  • Kwon, Jeong-Sik;Kim, Jin-Sung;Lee, Soo-Yong
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.41 no.3
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    • pp.194-200
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    • 2013
  • In this paper, the results of composite laminate mechanical joints test(ASTM D5961) are compared with the theoretical strength calculations and FEM analysis results. To calculate the S.C.F.(stress concentration factor) on joint strength, equations on metallic and composite materials in ASM Handbook used and compared with experimental results. The difference of joint strength are compared by geometrical parameters and joining types(single/double lap joint). In FEM analysis, to find efficient FEM model on composite laminate mechanical joint, several FEM models are compared with experimental test results.