• Title, Summary, Keyword: FEM

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Tool Deflection Estimation in Micro Flat End-milling Using Finite Element Method (유한요소법을 이용한 마이크로 평엔드밀링에서의 공구변형 예측)

  • Lim, Jeong-Su;Cho, Hee-Ju;Seo, Tae-Il
    • Journal of The Korean Society of Manufacturing Technology Engineers
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    • v.19 no.4
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    • pp.498-503
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    • 2010
  • The main purpose of this study strongly concerned micro machining error estimation by using FEM analysis of tool deflection shapes in micro flat end-milling process. For the precision micro flat end-milling process, analysis of micro cutting errors is mandatory. In general, tool deflection is a major factor which causes cutting error and limits realization of the high-precision cutting process. Especially, in micro end-milling process, micro tool deflection generates very serious problems in contrast to macro tool deflection. Methods which deal with compensation of cutting error by tool deflection in macro end-milling process have been studied plentifully but, few researches transact with micro scaled cutting tool deflection in micro cutting process. Therefore, the trend of micro tool deflection was estimated by using FEM analysis in this paper. Cutting forces were acquired by micro dynamometer and these were utilized in FEM analysis. In order to verify FEM analysis results, micro machining processes were carried out and real machined profiles were compared with FEM results. Finally through the proposed approach well suited FEM results were obtained.

Strain Gradient Crystal Plasticity Finite Element Modeling for the Compression Behaviors of Single Crystals (단결정 압축 변형 거동의 변형구배 결정소성 유한요소해석)

  • Jung, Jae-Ho;Cho, Kyung-Mox;Choi, Yoon Suk
    • Korean Journal of Materials Research
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    • v.27 no.12
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    • pp.679-687
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    • 2017
  • A strain-gradient crystal plasticity finite element method(SGCP-FEM) was utilized to simulate the compressive deformation behaviors of single-slip, (111)[$10{\bar{1}}$], oriented FCC single-crystal micro-pillars with two different slip-plane inclination angles, $36.3^{\circ}$ and $48.7^{\circ}$, and the simulation results were compared with those from conventional crystal plasticity finite element method(CP-FEM) simulations. For the low slip-plane inclination angle, a macroscopic diagonal shear band formed along the primary slip direction in both the CP- and SGCP-FEM simulations. However, this shear deformation was limited in the SGCP-FEM, mainly due to the increased slip resistance caused by local strain gradients, which also resulted in strain hardening in the simulated flow curves. The development of a secondly active slip system was altered in the SGCP-FEM, compared to the CP-FEM, for the low slip-plane inclination angle. The shear deformation controlled by the SGCP-FEM reduced the overall crystal rotation of the micro-pillar and limited the evolution of the primary slip system, even at 10 % compression.

Development of Financial Effect Measurement(FEM) Models for Quality Improvement and Innovation Activity (품질개선 및 혁신활동에서 재무성과 측정모형의 개발)

  • Choi, Sungwoon
    • Journal of the Korea Safety Management & Science
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    • v.17 no.1
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    • pp.337-348
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    • 2015
  • This research introduces the Financial Effect Measurement (FEM) models which measures both the improvement and the innovation performance of Quality Control Circle (QCC) and activities of Six Sigma. Concepts and principle of Comprehensive Income Statement (CIS), Balanced Scorecard (BSC), Time-Driven Activity Based-Costing (TDABC) and Total Productive Maintenance (TPM) are applied in order to develop the 4 FEM models presented in this paper. First of all, FEM using CIS depicts the improvement effects of production capacity and yield using relationships between demand and supply, and line balancing efficiency between bottleneck process and non-bottleneck processes. Secondly, cause-and-effect relation of Key Performance Indicator (KPI) is used to present Critical Success Factor (CSF) effects for QC Story 15 steps of QCC and DMAIC (Define, Measure, Analyze, Improve, and Control) of Six Sigma. The next is FEM model for service management innovation activities that uses TDABC to calculate the time-driven effect for improving the indirect activities according to the cost object. Lastly, FEM model for TPM activities presents the interpretation of improvement effect model of TPM Capital Expenditure (CAPEX) and Operating Expenditure (OPEX) maintenance using profit, cash and Economic Added Value (EVA) as metrics of enterprise values. To better understand and further investigate FEMs, recent cases on National Quality Circle Contest are used to evaluate new financial effect measurement developed in this paper.

Mechanical Performance Evaluation of Cement Paste with Foaming Agent using FEM Analysis Based on Picture Image (화상 이미지 기반 FEM 해석을 이용한 기포제 혼입 시멘트 페이스트의 역학 성능 평가)

  • Kim, Bo-Seok;Shin, Jun-Ho;Lee, Han-Seung
    • Journal of the Korea Institute of Building Construction
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    • v.16 no.1
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    • pp.35-43
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    • 2016
  • Concrete is a representative heterogeneous material and mechanical properties of concrete are influenced by various factors. Due to the fact that pores in concrete affect determining compressive strength of concrete, studies which deal with distribution and magnitudes of pores are very important. That way, studies using picture imaging have been emerged. Studies on mechanical performance evaluation of structural lightweight foamed concrete and FEM analysis based on picture image are inadequate because lightweight foamed concrete has been researched for only non-structural. Therefore, in this study, cement paste with foaming agent to evaluate mechanical performance is made, FEM analysis with picture image is conducted and young's modulus of experiment and analysis are compared. In this study, dosage of foaming agent is determined 7 level to check pore distribution and water-binder ratio is determined 20% to progress research about structural light weight foamed concrete. Weight of unit volume is minimum at 0.8% of foaming agent dosage. However, weight of unit volume is increased over 0.8% of foaming agent dosage because of interconnection with independent pores. For FEM analysis, cement paste is photographed to use image analyzer(HF-MA C01). Consequently, the fact that Young's Modulus of experiment and FEM analysis are same is drawn by using OOF(Object Oriented Finite elements).

Evaluation of Hydration Heat of Mass Concrete with Capsulated Slurry PCM and FEM Study for Analyzing Thermal Crack (캡슐형 슬러리 PCM을 혼입한 매스콘크리트의 수화열 평가 및 온도균열 FEM 해석에 관한 연구)

  • Park, ChangGun;Kim, Bo-Hyun;Lee, Han-Seung
    • Journal of the Korea Institute of Building Construction
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    • v.14 no.5
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    • pp.379-388
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    • 2014
  • The purpose of this study is to investigate the effect of capsulated slurry phase change material (PCM) on the thermal crack in mass concrete by experimental work and FEM analysis. In this study, three conditions of samples were prepared for evaluating the level of hydration heat, i.e., a material condition, a cement paste condition and a concrete condition. Also, a compressive strength test was conducted for FEM inverse analysis. Based on the results of the experiment, exothermic function coefficients of concrete with encapsulated slurry PCM were deducted by the inverse analysis. After that, they applied to FEM analysis of the mass scale concrete structures. From the results of this experiment, $31^{\circ}C$ capsulated slurry PCM had no super cooling phenomenon in the material condition. In the cement condition, hydration heat decreased by 34.61J when PCM of 1g was mixed. In the concrete condition, PCM of 6% was deducted as the best level in hydration heat absorption. In FEM inverse analysis, rate coefficient of reaction gradually decreased when PCM mixing ratio increased. But, temperature-rise coefficient increased when PCM mixing ratio exceeded 6%. For the inversed exothermic function coefficients applying to large scale concrete structures, a thermal cracking index increased by 0.05 when PCM of 1% was mixed.

Comparison of Two Methods for Analyzing Stress-Strain Behavior of Soil Beam (지반보의 응력-변형률 거동에 대한 해석법 비교)

  • Lee, Seung-Hyun;Han, Jin-Tae
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.19 no.12
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    • pp.294-302
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    • 2018
  • To analyze the behavior of a soil beam under pore water pressure, the results of analytical solutions and finite element analysis (FEM) were compared quantitatively. In contrast to the results of the analytical solution, the horizontal stress obtained from the FEM did not show a symmetrical distribution. On the other hand, the horizontal stress became closer to symmetrical distribution as the number of elements of the soil beam were increased. A comparison of the horizontal stresses from the analytic solution with those obtained from Gaussian points of FEM showed that the magnitude of the tensile stress from the FEM using 3 elements was 6% of the maximum value of the analytical solution and the compressive stress from the FEM using the same elements was 37% of the maximum value of the analytical solution. The magnitude of the tensile stress from the FEM using 6 elements was 61% of the maximum value of the analytical solution and the magnitude of the compressive stress from the FEM using the elements was 83% of the maximum value of the analytical solution. Vertical stresses, which were obtained from the analytical solution, showed a continuous distribution with the depth of the soil beam, whereas the vertical stresses from the FEM showed a discrete distribution corresponding to each element. The results also showed that the average value of the vertical stresses of each element was close to that of the pore water pressure. A comparison of the vertical displacements computed at the near vertical center line of the soil beam from the FEM with those of the analytical solution showed that the magnitude of the vertical displacement from FEM using 3 elements was 35% of the value of the analytical solution and the magnitude of the vertical displacement from FEM using 6 elements was 57% of the value of the analytical solution.

The Design of Levitation Magnet for UTM(Urban Transit Maglev)-02 using Maxwell-3D FEM (Maxwell-3D FEM을 이용한 UTM(Urban Transit Maglev)-02 의 부상용 전자석 설계)

  • Kim, Bong-Seop
    • Proceedings of the KIEE Conference
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    • pp.699-701
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    • 2000
  • It leaves much room for improvement that UTM-01 is of practical use. Therefor we will design of UTM-02 system. The design of new magnet is based on light weight for bogie system. We used Maxwell-3D FEM for design of new magnet. The new magnet for UTM-02 that was reduced weight of magnet. 22kg, then it was increased ratio lift to weight is 9.87.

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Optimal Design of Rotor Pole of BLDC Motor Using Taguchi Method and FEM (Taguchi 방법과 FEM을 이용한 BLDC 전동기 회전자 자극의 최적설계)

  • Kim, J.H.;Lee, H.K.;Kwon, Y.A.
    • Proceedings of the KIEE Conference
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    • pp.40-42
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    • 2002
  • This paper presents the optimal design of BLDC motor keeping the average torque and cogging toruqe of the initial model while minimizing the volume of magnet pole by FEM and Taguchi method. Experimental tests are performed by Finite element method, and the second order polynomial equations are obtained from FEM results due to design parameter variation referred to orthogonal arrays by Taguchi. The presented optimization shows a big reduction of computation time and a largely reduced volume of magnet pole.

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Surface Temperature in Sliding Systems Using the FFT Finite Element Analysis (FFT-FEM을 이용한 윤활 기구에서 표면온도에 관한 연구)

  • 조종두;안수익
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • pp.73-79
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    • 1999
  • Finite element equations by using fast Fourier transformation were formulated for studying temperatures resulting from frictional heating in sliding systems. The equations include the effect of velocity of moving components. The program developed by using FFT-FEM that combines Fourier transform techniques and the finite element method, was applied to the sliding bearing system. Numerical prediction obtained by FFT-FEM was in an excellent agreement of experimental temperature measurements.

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Design of Forming Roll using FEM (FEM을 이용한 Forming Roll 설계)

  • Yoon Hyung-Joon;Yoon Young-Sik
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.761-764
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    • 2005
  • In this paper, multi-pass roll forming process is simulated with a commercial FEM software. From these simulations, detects like excessive thickness decrease were estimated. And effects of springback, idle roll without force, and self-contacts between materials were also predicted. As a result, the defects of the forming process and the numbers of the roll pass can be decreased. And these analyses will be able to design the optimal roll forming process.

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