• Title, Summary, Keyword: 준정적해석

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금속 성형 공정의 준정적 변형 예측을 위한 외연적 시간 적분 유한 요소법의 적용성 연구

  • 유요한;양동열
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.192-197
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    • 1995
  • 소재의 손실을 최소한 줄이면서 원하는 형상의 제품을 가공하는 가장 기본적인 금속 가공 방법은 금형을 이용하는 금속 성형(metal forming)이다. 본 논문에서는 준정적 금속 성형 문제 해석 에대한 외연적 시간 적분 유한 요소법의 적용성을 평가 하기 위하여 변형모드가 복잡한 박판튜브 (thin-walled tube)의 좌굴문제를 해석하여 변형과정이 이론 및 실험결과와 비교적 잘 일치하는지 살펴보기로 한다. 또한 준정적 금속 성형 문제 해석에 외연적 시간 적분 유한 요소법을 사용할 때 계산 시간을 줄이기 위하여 많이 사용되는 가압속도 조절법(loading velocity control technique) 의 타당성을 평가하기 위하여 박판 튜브와 중실 실린더(solid cylinder)의 변형 속도에 따른 변형 모드의 변화를 비교 관찰하여 기하학적 형상에따른 가압속도 조절법의 적용 가능 여부를 분석하여 보겠다.

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A Dynamic Structural Analysis System for Propeller Blades (프로펠러 날개의 동적 구조해석 시스템 개발)

  • 노인식;이정렬;이현엽;이창섭
    • Journal of the Society of Naval Architects of Korea
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    • v.41 no.2
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    • pp.114-120
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    • 2004
  • Propeller blades have complex airfoil section type geometry and the thickness is continuously varied to both its length and cord-wise direction. in the present research, the finite element analysis program PROSTEC (Propeller Stress Evaluation Code) is developed to calculate the structural responses of propeller blades in irregular ship wake field. To represent the curved and skewed geometry of propeller blades accurately, 20-node curved solid element using the quadratic shape function is adopted. Input data for the analysis including the geometry and pressure distribution of propeller blades can be generated automatically from the propeller design program. And to visualize the results of analysis on windows system conveniently, the post processor PROSTEC-POST is developed.

A Protection Capacity Evaluation of Vessel Protective Structures by Quasi-Static Collision Analysis (준정적 충돌해석을 통한 선박충돌방공호의 방호능력평가)

  • Lee, Gye-Hee
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.24 no.6
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    • pp.691-697
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    • 2011
  • In this study, the vessel collision protective structure and the vessel were modeled numerically and the quasi-static collision analysis was performed to evaluate the maximum protection capacity. In the modeling process of protective structure, the nonlinear behaviors of structure and the supporting conditions of ground including pull-out action were considered. In that of collision vessel, the bow of vessel was modeled precisely, because of the nonlinear behaviors were concentrated on it. For the efficient analysis, the mass scaling scheme was applied, also. To evaluate the differences and efficiency, the dynamic analyses were performed for the same model, additionally. Based on the obtained energy dissipation curves of the structure and the vessel, the moment that the collision force affected to the bridge substructures was determined and the maximum allowable collision velocity was evaluated. Because of the energy dissipation bound can be recognized clearly, this scheme can be used efficient in engineering work.

Characteristic Analysis of the Asymmetric Coupled microstrip Lines with finite Metalization Thickness in the Multilayered Structure (다층구조에서 도체 두께를 고려한 비대칭 결합선로의 특성해석)

  • 윤남일;홍익표;박한규
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.25 no.3A
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    • pp.424-429
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    • 2000
  • In this paper, the characteristics of the asymmetric coupled microstrip(ACM) lines with finite metalization thickness are investigated using the quasi-static analysis in the multilayered structure. By mode-matching method as the quasi-static analysis. the characteristic impedances and effective dielectric constants in ACM lines are obtained as a function of metalization thickness. The numerical results show that the propagation characteristics of ACM lines in the single and multilayered structure will be changed by the variation of metalization thickness.

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Sensitivity Analysis of the Explicit Elasto-plastic Finite Element Method and Application to the Quasi-static Deformation (외연적 탄소성 유한요소해석에서의 민감도 해석과 준정적 변형에의 응용)

  • Kim, Se-Ho;Huh, Hoon
    • Proceedings of the KSME Conference
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    • pp.402-407
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    • 2001
  • Sensitivity analysis scheme is developed in the elasto-plastic finite element method with explicit time integration using direct differentiation method. The direct differentiation is concerned with the time integration, constitutive relation, shell element with reduced integration and the contact scheme. Sensitivity analysis results are mainly examined with the highly nonlinear and quasi-static problem with the complicated contact condition. The result shows stable sensitivity especially in the sheet metal forming analysis.

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Technical Papers : Optimization Method of Structure by Using Coupled Load Analysis (기술논문 : 연성하중해석을 이용한 구조 최적화 기법 연구)

  • Lee,Yeong-Sin;Kim,In-Geol;Hwang,Do-Sun
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.30 no.1
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    • pp.132-138
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    • 2002
  • Of srategic importance nowdays is the development of high performance spacecraft bus. In this study, optimization for spacecraft structure is performed under the framework of coupled load analysis which is a branch of component mode synthesis with constrained mode and modal transient analysis. unlike the traditional method which uses the quasi-static table supplied by launch vehicle contractor, the present method adots the load results of previous coupled load analysis. It if shown that the proposed method can serve as a effective tool for the optimization spacecraft structure in the early stage of design and weight reduction by numerical example.

Evaluation of the Structural Stability of Platform Screen Door (PSD) due to Train Wind Pressure (열차 진입 시 풍압에 의한 완전 밀폐형 승강장 스크린 도어(PSD)시스템의 구조 안정성 평가)

  • Lee, Jae-Youl;Ryu, Bong-Jo;Kim, Dong-Hyun;Lee, Eun-Kyu;Shin, Kwang-Bok
    • Journal of the Korean Society for Railway
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    • v.9 no.5
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    • pp.594-600
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    • 2006
  • In this study, transient and quasi-static analysis were done for the evaluation of structural integrity of the platform screen door due to train wind pressure. Fluent 6.0 was used to calculate the train wind pressure, and Ansys 10.0 was used to evaluate the structural stability of platform screen door due to train wind pressure. Transient analysis was used to check the design requirements of platform screen door, and quasi-static analysis was introduced to save the calculating time and check quickly structural performances when compared to those of transient analysis. The results show that structural stability of the platform screen door under train wind pressure is proven and quasi-static analysis can quickly check the structural integrity of platform screen door.

Evaluation of the Structural Stability of Platform Screen Door(PSD) (승강장 스크린 도어(PSD)시스템의 구조 안정성 평가)

  • Lee, Jae-Youl;Ryu, Bong-Jo;Jeon, Jae-Sun;Kim, Dong-Hyun;Lee, Eun-Kyu;Shin, Kwang-Bok
    • Proceedings of the KSR Conference
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    • pp.1190-1197
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    • 2006
  • We have evaluated the structural stability of a platform screen door due to train wind pressure. The platform screen door was installed at the ground and underground station and had 65 meters in length. Also, the platform screen door was a safety device because it was placed between the train and the platform. The finite element analysis was used to calculate the stresses and deflections of platform screen door caused by wind pressure using ANSYS 10.0. Quasi-static analysis was introduced to save calculating time and check quickly structural performances when compared to those of transient analysis. The results show that structural stability of the platform screen door under train wind pressure is proven and quasi-static analysis can quickly check the structural integrity of platform screen door.

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Application of the Durability Reinforcement Technique on the Frame Structure (프레임 구조물에 대한 선형 내구 보강 기법의 적용)

  • Kwon, Sung-Hun;Yoo, Hong-Hee
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.33 no.11
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    • pp.1341-1346
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    • 2009
  • In this paper, the technique to reinforce the durability performance of structure using the sensitivity information for the frame structure is applied. The fatigue life calculation for the frame structure is performed from the quasi-static and transient analysis and the characteristics of two methods are compared for the fatigue analysis. Then the reinforcement technique is applied. First, some design variables related to the locations of fatigue failure is selected. Then sensitivities of fatigue life at fracture points with respect to the variation of design variables are calculated and the vector composed of gaps between the target life and initial life cycles is calculated. If the number of fatigue fracture points is same as the number of design variables, the variations of the design variables are calculated from the linear algebraic equation. If not, the variations of the design variables are calculated from the optimization formulation with the constraints.

Quay Mooring Analysis (안벽계류해석)

  • Tae-Myoung,Oh;Deuk-Joon,Yum
    • Bulletin of the Society of Naval Architects of Korea
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    • v.27 no.3
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    • pp.47-55
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    • 1990
  • This paper presents the quasi-static mooring analysis model for a vessel moored at the quay. The results of this analysis will aid the designer in determining the mooring configuration for the surface vessels subjected to wind, current and wave forces. And it will also help him in selecting the equipment for the fixed mooring system. The cumulative elastic behavior of the mooring lines invokes a complicated nonlinear problem since the mooring lines are relatively short and hang in air as noncoplanar configurations. This nonlinear mooring problem is solved in this paper by the load increment technique in which the external load is increased step by step taking all sources of nonlinearity into account.

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