• 제목/요약/키워드: 허훈(許薰)

검색결과 355건 처리시간 0.023초

토목구조물 시공현장 암질 분류 기준에 대한 제안

  • 허훈;이재찬
    • 한국암반공학회:학술대회논문집
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    • 한국암반공학회 1995년도 정기총회 및 학술발표회
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    • pp.186-201
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    • 1995
  • 암질분류는 구조물의 설계 및 시공에 영향을 미치는 기본요소를 선택하여 현장에서 관찰, 계측한 후 일정기준에 따라 암반을 등급별로 구분하는데 목적이 있다. 이와 같은 암질분류는 댐, 도로, 터널 등의 설계 및 시공의 각 단계를 통하여 경제성과 안정성에 밀접한 상관 관계를 가지며 중대한 영향을 끼치게 된다. 따라서 암질분류기준은 객관적이고 간편하며 모든 암반에 적용이 가능하여야 하고 구조물의 설계 및 시공에 필요한 정보를 제공하여야 한다. (중략)

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유연성을 고려한 인공위성의 자세제어를 위한 GA 튜너와 퍼지제어기 설계 (Design of GA(Genetic Algorithm) based Fuzzy Logic Controller for the control of flexible satellite structural system)

  • 김민성;최완식;오화석;허훈
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 1996년도 추계학술대회논문집; 한국과학기술회관, 8 Nov. 1996
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    • pp.160-165
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    • 1996
  • Nonlinear Attitude Dynamic Equation for fleable-body satellite is drived and confirmed the effect of flexible body. GA based Fuzzy Logic Controller is designed. Also, Bang-bang controller is designed for compare the performance, Fuzzy controller chows much batter result then those by using of Bang-Bang controller.

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유전자알고리즘을 이용한 우주비행체의 자세제어 (Attitude Control for Spacecraft by using Genetic Algorithm)

  • 허훈;김대중
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 1996년도 추계학술대회논문집; 한국과학기술회관, 8 Nov. 1996
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    • pp.182-186
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    • 1996
  • Control of flexible spacecraft is investigated. GA(Genetic Algorithm) based Fuzzy Logic Controller is designed to implement for the attitude control of flexible satellite. The results obtained by employing GA based FLC are compared with those by FLC. It shows much shorter settling time and smaller tip mass oscillation.

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변형률 공간에서 변형률속도 및 온도를 고려한 구성방정식의 개선된 적분방법 (Modified Integration Algorithm on the Strain-Space for Rate and Temperature Dependent Elasto-Plastic Constitutive model)

  • 조상순;허훈
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 2007년도 춘계학술대회 논문집
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    • pp.272-275
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    • 2007
  • This paper is concerned with modified integration algorithm on the strain-space for rate and temperature dependent elasto-plastic constitutive relations in order to obtain more accurate results in numerical implementation. The proposed algorithm is integrated analytically using integration by part and chain rule and then is applied to the 2-stage Lobatto IIIA with second-order accuracy. It has advantage that is able to consider the convective stress rates on the yield surface of the strain-space. Also this paper is carried out the iteration procedure using the Newton-Raphson method to enforce consistency at the end of the step. And the performance of the proposed algorithm for rate and temperature dependent constitutive relation is illustrated by means of analysis of adiabatic shear bands.

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굽힘이력을 고려한 원형컵 딥드로잉공정의 유한요소역해석 (Finite Element Inverse Analysis of the Cylindrical Cup Deep Drawing Process Considering Bending History)

  • 허지향;윤종헌;바오이동;허훈
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 2007년도 춘계학술대회 논문집
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    • pp.340-343
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    • 2007
  • This paper introduces a new approach to consider the bending history in finite element inverse analysis of the cylindrical cup drawing. A modified membrane element is adopted to add the bending-unbending energy to the total plastic energy on the bending-unbending region predicted from the geometry of the final shape and tools. The algorithm suggested was applied to a cylindrical cup deep drawing process. The blank shape and the distribution of the thickness strain are compared with those obtained from incremental finite element analysis. The comparison demonstrates the algorithm proposed reduces the difference between the results from inverse analysis and those from incremental analysis when the bending history is considered.

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해밀토니안의 시간 불연속 변분적분기를 이용한 2차원 탄소성 응력파 해석 (Analysis of 2-Dimensional Elasto-Plastic Stress by a Time-Discontinuous Variational Integrator of Hamiltonian)

  • 조상순;허훈;박광춘
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 2008년도 추계학술대회 논문집
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    • pp.263-266
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    • 2008
  • This paper is concerned with the analysis of elasto-plastic stress waves in a mode I semi-infinite cracked solid subjected to Heaviside pulse load. This study adopts a time-discontinuous variational integrator based on Hamiltonian in order to reduce the numerical dispersive and dissipative errors. This also utilizes an integration scheme of the constitutive model with 2nd-order accuracy which is formulated on the strain space for a rate and temperature dependent material model. Finite element analyses of elasto-plastic stress waves are carried out in order to compare the accuracy between a conventional Galerkin method and the time- discontinuous variational integrator.

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차량충돌해석 적용을 위한 간단화한 성형이력 고려 방법 (A Simplified Method to Consider Forming Effects in a Car Crash Analysis)

  • 허지향;윤종헌;임지호;박성호;허훈
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 2008년도 추계학술대회 논문집
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    • pp.259-262
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    • 2008
  • This paper introduces a simplified method to consider forming effects in a car crash analysis. Representative value was used to consider forming effects simply. Four representative values, which are the mean value of thicknesses and effective plastic strains at nodes, the median of thicknesses and effective plastic strains at nodes, were evaluated. A crash analysis of a front side member shows that analysis results from the suggested methods are similar to those from the conventional method to consider forming effects. Use of the mean effective plastic strain shows the best results. A car crash analysis for a ULSAB/AVC model under the condition of US SINCAP were carried out to demonstrate the validity of the suggested method. Analysis results show that the error of suggested method is less than 1.5%.

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유한요소해석을 이용한 스틸코드 롤러교정공정의 영향인자 분석 (Parameter Study of Roller Leveling Process of Steel Cord Using Finite Element Analysis)

  • 배기현;이종섭;허훈;이준우
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 2008년도 추계학술대회 논문집
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    • pp.245-248
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    • 2008
  • This paper deals with the parameter study of roller leveling process of steel cord using finite element analysis. A simplified model of roller leveling process is constructed for the efficient numerical simulation considering the computing time. Using the constructed simulation scheme, the parameter study of main process parameters, such as back-tension and intermesh, is carried out in order to evaluate elastic recovery angle and roller force quantitatively. The effect of the initial shape of steel cord is also evaluated during the parameter study. And the mechanism of roller leveling process is verified by investigating the residual stress distribution.

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