• Title/Summary/Keyword: 강-소성 모델

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A Comparative Study on Formulation of Three-Dimensional Elastic-Plastic Finite Deformation Analysis for Prediction Large Deflection (강부재의 대변형 예측을 위한 3차원 탄소성 유한변위해석의 정식화에 대한 비교연구)

  • Jang, Gab-Chul;Chang, Kyong-Ho
    • Journal of Korean Association for Spatial Structures
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    • v.6 no.4 s.22
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    • pp.53-61
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    • 2006
  • In th is paper, to predicting the large deformation and cyclic plastic behavior of steel members under loading, 3-Dimensional elastic-plastic FE analysis method is developed by using finite deformation theory and proposed cyclic plasticity model. finite deformation theory, described the large deformation, is formulated by using Updated-lagrangian formulation and Green's strain tensor, Jaumann's derivative of Kirchoff stress. Also, cyclic plasticity model proposed by author is applied to developed analysis method. To verification of developed analysis method, analysis result of steel plate specimen compare to the analysis result using infinitesimal deformation theory and test result. Also, load-displacement and deflection shape, analysis result of pipe-section steel column, compare to test result. The good agreement between analysis result and experiment result shown that developed 3-dimensional finite element analysis can be predict the large deformation and cyclic plastic behavior of steel members.

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모델 재료를 이용한 대형 개방형 단조품의 성형에 관한 연구

  • Lee, Geun-An;Im, Yong-Taek;Lee, Jong-Su;Hong, Seong-Seok;Jo, Nam-Chun
    • Transactions of Materials Processing
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    • v.1 no.2
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    • pp.52-62
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    • 1992
  • 본 연구에서는 모델재료를 이용한 모사실험을 통하여 고온의 강을 단조하였을 때의 유동과 변형 그리고 하중을 검토하고, 이어 성형에 관한 연구를 하였다. 모델재료인 플라스티신은 고용의 강을 모사하는데 많이 쓰이는데, 실험을 통하여 플라스티신과 강과의 변형저항식을 비교 검토하였다. 이 실험결과 상사성이 어느정도 일치함을 알았고, 이 상사성 결과를 이용하여 실제와 모델사이의 하중과 응력비를 검출하였다. 이로써 플라스티신을 이용한 단조 압축 실험을 통하여 실제의 하중을 예측하였다. 또한 예비 성형체를 설계하기 위하여 앞서 실험한 결과들을 이용하여 초기의 실린더의 체적과 치수를 결정하고 이에 단계에 따른 성형과정을 통하여 예비 성형체를 만들었는데, 이는 제한된 용량으로 성형하여야 하는 문제를 해결하기 위함이었다. 실험 결과 8단계에 따른 성형과정에 의해 우리가 원하는 대형 단조품을 성형할 수 있음을 알았다.

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Damage Curves of the Fixed Ends Beam with the Rigid-Plastic Model (강-소성 모델을 이용한 양단 고정보의 손상곡선)

  • Kim, Seok Ki
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.8 no.4
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    • pp.239-246
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    • 2004
  • The fixed ends beam is analyzed by the s d 0 f system with the rigid-plastic model. And the safety criteria of the fixed ends beam to the Impulsive loads are established with the peak-load ratio to the static collapse load and impulse ratio to the ideal impulse producing the critical displacement. It is shown that the impulse and the peak-load of the impulsive loads are the important factors for the damage of the structures. It is also shown that the damage curves with the peak-load and impulse ratio are useful method to estimate the damage of the structures due to the emphasis on the equivalent dynamic loads rather than the equivalent static loads in the process of deriving the curve.

A Prediction of Behavior of Granular Soils Based on the Advanced Elasto Plastic Model (개선된 탄.소성 구성모델을 이용한 사질토의 응력-변형률 거동예측)

  • Park, Byeong-Gi;Im, Seong-Cheol;Lee, Gang-Il
    • Geotechnical Engineering
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    • v.11 no.3
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    • pp.81-90
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    • 1995
  • Based on the close investigation of Lade elasto -plastic model, this study proposes a new elasto -plastic constitutive model for foundation composed of granular soils. The new model contains 1st stress invariant in plastic potential function as well as yield function, which is different from Lade original model. Both these functions called a correction function include a correction term. To validate the new analytical model, it was compered with some previous models. Comparison between the test results and numerical results using Lade and new model was carried out concerning Sacramento River sand, U.S.A and Backma River sand. The conclusion was obtained that more refined model well be deft.eloped throughout this research.

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소성가공

  • Baek, Nam-Ju
    • Journal of the Korean Society for Precision Engineering
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    • v.1 no.1
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    • pp.23-29
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    • 1984
  • 소성역학에 의해서 소성가공중의 현상을 해석하여 제품의 형상, 강도, 잔유응력, 가공력, 가공한계 및 결함의 발생등을 견적하고 이것에 의해 가공기계의 강도, 강성 및 제어량등이 결정된다. 또 재질에 대한 지침이 얻어진다. 탄성론이나 소성론에서 경계치 문제는 응력젼위방정식, 응력의 경계조건, 변위에 관한 변위 스트레인 관계식과 변위의 경계조건, 그리고 응력과 스트레인을 관계시 키는 구성방정식으로 되어 있는 기초방정식으로 구성된다. 문제의 구성방정식은 재료의 거동이 매우 복잡하기 때문에 실제의 거동을 충실히 표시 할 수 없다. 재료의 이방성, 유한도형, 이방성주축의 회 전, 가공경화, 고온, 고속가공 등에 의해서 재료의 변형거동은 매우 복잡해진다. 이상의 정량적 고찰 과 전위 또는 결정의 슬립모델과 같은 정성적 고찰도 있다.

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A Study on Seismic Performance of High-Strength Steel(POSTEN60, POSTEN80) Pipe-Section Piers using 3-Dimensional Elastic-Plastic Finite Deformation Analysis (3차원 탄소성 유한변위해석을 이용한 고강도(POSTEN60, POSTEN80) 원형강교각의 내진성능에 관한 연구)

  • Chang, Kyong-Ho;Jang, Gab-Chul;Kang, Jae-Hoon
    • Journal of the Earthquake Engineering Society of Korea
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    • v.8 no.6 s.40
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    • pp.45-54
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    • 2004
  • Recently, as steel structures become higher and more long-spanned, application of high-strength steels is increasing gradually. For seismic design of steel structures using high-strength steels(POSTEN60, POSTEN80), analytical method, can describe the large deformation and inelastic cyclic behavior generated by non-proportional cyclic loading, are required. In this paper, cyclic plasticity model was proposed by results of monotonic loading tests ant cyclic loading tests. Three-dimensional finite element analysis is developed by using proposed model and finite deformation theory and verified as compare with experiment result. Using 3-dimensional elastic-plastic finite deformation analysis, seismic analysis of high-strength steel pipe-section piers are carried out. Also, seismic performance of high-strength steel pipe-section piers in parameter of diameter-thickness ratio was clarified.

The Characteristic for Undrainded Shear Behavior of in Low-Plastic Silt and its Prediction (저소성 실트의 비배수 전단거동 특성과 예측)

  • Kim, Daeman
    • Journal of the Korean GEO-environmental Society
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    • v.9 no.6
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    • pp.61-70
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    • 2008
  • In this study, undrained triaxial (CU) tests were performed on low-plastic silt of Nakdong River in order to investigate the undrained shear behavior of low-plastic silt. In experimental results, the deviator stress showed the hardening behavior after reaching its yield stress like the tendency of common sand, and the pore water pressure was gradually decreased to critical state after the maximum value. In the effective stress paths, regardless of consolidation stress or overconsolidation ratios, both a critical state line (CSL) and a phase transformation line (PTL) exist in the effective stress path that is similar to the case of sand. The behavior of low-plastic silt was predicted by the Modified Cam-Clay (MCC) model, the Jordan and the Elman-jordan model that is artificial neural network model. According to predicted results, the overall undrained shear behavior of low-plastic silt could not be predicted with the MCC model, but the Jordan and Elman-Jordan model showed well-matched experiment results.

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Reinforcement Effect of Viscoplastic Rockboft - Numerical Study (록볼트 점소성 거동에 의한 지보효과 분석 - 수치해석)

  • 조태진;이정인
    • The Journal of Engineering Geology
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    • v.3 no.3
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    • pp.215-230
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    • 1993
  • In-situ rock mass demonstrates the variety of structural features, and especially the mechanical and spatial characteristics of joint (or joint system) greatly affect the deformation and fallure strength of the rock mass. In this study finite element model capable of analyzing the viscoplastic behavior of reinforced jointed rock mass has been developed based on equivalent material approach. Accuracy and reliability of the numerical model have verified by simuiating the behavior of simplified block model and comparing the results with analytic solutions. Practical applicability was also demonstrated by analyzing the time-dependent behavior of underground oil storage tunnel and assessing the reinforcement effect of rockbolt.

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Analytical Model for Transfer Bond Performance of Prestressing Strands (PS 강선의 정착부착성능에 관한 해석 모델)

  • 유승룡
    • Magazine of the Korea Concrete Institute
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    • v.6 no.4
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    • pp.92-101
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    • 1994
  • A new analytical model is proposed to better understand the transfer bond performance in a prestressed pretensioned concrete beam. The transfer length is divided into an elastic and a plas tic zones in this model. The bond stress is assumed t.o increase proportionally with the slip t.o the lirnit of maximum bond stress within the elastic zone and remains at a constant maximum value wthin the plastic zone. Four main stress patterns: bond stress, slip, steel stress, and concrete stress distributions within the transfer length are obtained precisely. The total transfer length al\ulcornerd free-end slip obtained here give a close comparison to the test results by Cousins et al.

3-D Frame Design Using Second-Order Plastic-Hinge Analysis Accounting for Lateral Torsional Buckling (횡비틀림좌굴을 고려하는 2차 소성힌지해석을 이용한 3차원 강뼈대 구조물 설케)

  • 김승억;박주수
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.15 no.1
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    • pp.117-126
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    • 2002
  • In this paper, 3-D fame design using second-orders plastic-hinge analysis accounting for lateral torsional buckling is developed. This analysis accounts for material and geometric nonlinearities of the structural system and its component members. Moreover, the problem associated with conventional second-order plastic-hinge analyses, which do not consider the degradation of the flexural strength caused by lateral torsional buckling, is overcome. Efficient ways of assessing steel frame behavior including gradual yielding associated with residual stresses and flexure, second-order effect, and geometric imperfections are presented. In this study, a model consisting of the unbraced length and cross-section shape is used to account for lateral torsional buckling. The proposed analysis is verified by the comparison of the LRFD results. A case studs shows that lateral torsional buckling is a very crucial element to be considered in second-order plastic-hinge analysis. The proposed analysis is shown to be an efficient reliable tool ready to be implemented into design practice.