A Progressive Failure Analysis Procedure for Composite Laminates I - Anisotropic Plastic Constitutive Model

이규세,Yi, Gyu-Sei Korean Society for Advanced Composite Structures 2014 복합신소재학회논문집 Vol.5 No.4

A progressive failure analysis procedure for composite laminates is developed in here and in the companion paper. An anisotropic plastic constitutive model for fiber-reinforced composite material, is developed, which is simple and efficient to be implemented into computer program for a predictive analysis procedure of composites. In current development of the constitutive model, an incremental elastic-plastic constitutive model is adopted to represent progressively the nonlinear material behavior of composite materials until a material failure is predicted. An anisotropic initial yield criterion is established that includes the effects of different yield strengths in each material direction, and between tension and compression. Anisotropic work-hardening model and subsequent yield surface are developed to describe material behavior beyond the initial yield under the general loading condition. The current model is implemented into a computer code, which is Predictive Analysis for Composite Structures (PACS), and is presented in the companion paper. The accuracy and efficiency of the anisotropic plastic constitutive model are verified by solving a number of various fiber-reinforced composite laminates with and without geometric discontinuity. The comparisons of the numerical results to the experimental and other numerical results available in the literature indicate the validity and efficiency of the developed model.

A Progressive Failure Analysis Procedure for Composite Laminates II - Nonlinear Predictive Finite Element Analysis

이규세,Yi, Gyu-Sei Korean Society for Advanced Composite Structures 2014 복합신소재학회논문집 Vol.5 No.4

A progressive failure analysis procedure for composite laminates is completed in here. An anisotropic plastic constitutive model for fiber-reinforced composite material is implemented into computer program for a predictive analysis procedure of composite laminates. Also, in order to describe material behavior beyond the initial yield, the anisotropic work-hardening model and subsequent yield surface are implemented into a computer code, which is Predictive Analysis for Composite Structures (PACS). The accuracy and efficiency of the anisotropic plastic constitutive model and the computer program PACS are verified by solving a number of various fiber-reinforced composite laminates with and without geometric discontinuity. The comparisons of the numerical results to the experimental and other numerical results available in the literature indicate the validity and efficiency of the developed model.

부착모델을 이용한 강-콘크리트 합성바닥판의 간략 해석

이규세,Yi. Gyu-Sei 한국방재학회 2011 한국방재학회논문집 Vol.11 No.4

In this study, a bond model, which is used to evaluate the behavior of the steel-concrete decks, is proposed. The load-end slip relation in the proposed model is formulated by Newmark theory. The steel-concrete decks are analyzed by finite element analysis with the aid of the proposed bond model. In the finite element analysis, the shear connectors between the steel plate and the concrete are modeled by a number of spring elements. The results of the finite element analysis with the proposed bond model are fairly correlated with the experimental results of the full-size model. This study furthermore indicates that, if the proposed bond model is properly used in the analysis of steel-concrete composite deck, the behavior of the composite deck can be easily analyzed without the aid of the full-size experiment. 본 논문은 강-콘크리트 합성바닥판의 구조적 거동을 간략하게 예측할 수 있도록 부착 모델을 제시하였다. 제안한 부착모델의 단부 슬립 관계는 Newmark 이론을 이용하여 유도되었다. 제안한 부착모델을 이용하여 강-콘크리트 합성바닥판의 유한요소 구조해석을 실시하였다. 유한요소해석에서 콘크리트와 강바닥판 사이의 전단연결재는 스프링요소를 사용하여 모델링하였다. 제안한 부착모델을 이용한 유한요소해석 결과와 실물모형 실험결과는 매우 일치하였다. 따라서, 본 연구 결과는 제안된 부착모델을 적절히 사용한다면 강-콘크리트 합성바닥판의 거동을 실물모형실험 없이도 예측할 수 있음을 보였다.

건설분야에서의 복합신소재 이용기술 -복합신소재 바닥판을 중심으로-

이규세,박원태,Yi, Gyu-Sei,Park, Won-Tae 한국복합신소재구조학회 2010 복합신소재학회논문집 Vol.1 No.1

복합재료 거동특성의 파괴해석 2 -비선형 유한요소해석

이규세 ( Gyu Sei Yi ) 한국복합신소재구조학회 2014 복합신소재구조학회논문집 Vol.5 No.4

A progressive failure analysis procedure for composite laminates is completed in here. An anisotropic plastic constitutive model for fiber-reinforced composite material is implemented into computer program for a predictive analysis procedure of composite laminates. Also, in order to describe material behavior beyond the initial yield, the anisotropic work-hardening model and subsequent yield surface are implemented into a computer code, which is Predictive Analysis for Composite Structures (PACS). The accuracy and efficiency of the anisotropic plastic constitutive model and the computer program PACS are verified by solving a number of various fiber-reinforced composite laminates with and without geometric discontinuity. The comparisons of the numerical results to the experimental and other numerical results available in the literature indicate the validity and efficiency of the developed model.

신형식 강합성 교량의 연석고정하중 분배계수

이규세(Yi, G.S.) 한국산학기술학회 2010 한국산학기술학회논문지 Vol.11 No.7

본 논문에서는 신형식 강합성 교량에 대한 3차원 유한요소해석을 ABAQUS를 이용하여 실시하여, 연석 사하 중 재하에 따른 하중분배값을 검토하였다. 하중분배계수 검토에 고려된 변수로는 콘크리트 슬래브 두께, 강판 두께, 주형길이가 적용되었다. 해석을 통해 얻어진 하중 분배율은 AASHTO Standard와 AASHTO LRFD 설계기준의 제안식 및 기존 연구자들이 제안한 식들과 비교·검토되었다. 본 논문에서는 신형식 강합성 교량의 설계 간편성을 고려하여 외측주형의 경우 0.67, 내측주형의 경우 0.34의 하중분배율을 제안하였다. The load distribution factor (LDF) values of new composite I-beam panel bridges that were subjected to dead load were investigated using three-dimensional finite element analyses with the computer program ABAQUS(2007). This study considered some design parameters such as the slab thickness, the steel-plate thickness, and the span length for design of new composite bridges. The distribution values that were obtained from these analyses were compared with those from the AASHTO Standard, AASHTO LRFD, and the equations presented by Tarhini and Frederick, and Back and Shin. For the simple application of the design, bridge engineers can use the LDF of 0.67 for the exterior girder and of 0.340 for the interior girder.

취임사

이규세 ( Gyu Sei Yi ) 한국복합신소재구조학회 2013 복합신소재학회논문집 Vol.4 No.4

차량 하중 방향 변경에 의한 기존교량의 피로안정성 연구

이규세(Yi, G.S.),이승열(Lee, Sung-Yol) 한국산학기술학회 2009 한국산학기술학회논문지 Vol.10 No.8

도로 건설 중 기존 교량에 가교를 접속하여 사용하는 경우가 종종 발생 한다. 이 경우 차량 하중 방향의 변경으로 인하여 기존 교량의 주형의 설계 시 고려하지 못한 피로 안정성 문제가 발생할 수 있다. 따라서 본 연구에 서는 기존 교량의 내민 슬라브와 주형의 안정성을 도로교 설계기준의 허용 피로 응력을 이용하여 검토 하였다. 응력 변동이 가장 큰 지점은 가교 접속 구간의 교량 시점에서 55m 떨어진 지점부, 그리고 교량 시점과 지점부 사이의 중 앙점(교량 시점에서 32.5m 떨어진 지점)의 응력 변동이 크다는 것을 알 수 있었다. 이에 대한 기존 교량의 내민 슬 라브와 주형에 보강이 필요함을 확인하여 보강대책을 수립하였고 보강 후 가교와 기존 교량의 피로 안정성 검토를 다시 수행 하여, 도로교 설계 기준의 허용 피로 응력에 만족함을 확인하였다. During a construction of a road, a temporary bridge is often connected to a existing bridge. In this case, a fatigue stability problem, which was not considered in the design of the bridge, can be occurred in the main girder of the existing bridge due to the vehicle load direction change. In this study, the fatigue stability of the main girder and cantilever slab of the bridge was tested with the allowable fatigue stress of the design specifications of the road bridge. The big stress change was occurred at 55m away from the support, and the middle of the span. Furthermore, the excess of the allowable fatigue stress of the design specifications of the road bridge was confirmed at the cross section. The bridge after the reinforcement was tested for the fatigue stability, and it was confirmed that the bridge is safe.

복합재료 거동특성의 파괴해석1 -이방성 소성 적합모델

이규세 ( Gyu Sei Yi ) 한국복합신소재구조학회 2014 복합신소재구조학회논문집 Vol.5 No.4

A progressive failure analysis procedure for composite laminates is developed in here and in the companion paper. An anisotropic plastic constitutive model for fiber-reinforced composite material, is developed, which is simple and efficient to be implemented into computer program for a predictive analysis procedure of composites. In current development of the constitutive model, an incremental elastic-plastic constitutive model is adopted to represent progressively the nonlinear material behavior of composite materials until a material failure is predicted. An anisotropic initial yield criterion is established that includes the effects of different yield strengths in each material direction, and between tension and compression. Anisotropic work-hardening model and subsequent yield surface are developed to describe material behavior beyond the initial yield under the general loading condition. The current model is implemented into a computer code, which is Predictive Analysis for Composite Structures (PACS), and is presented in the companion paper. The accuracy and efficiency of the anisotropic plastic constitutive model are verified by solving a number of various fiber-reinforced composite laminates with and without geometric discontinuity. The comparisons of the numerical results to the experimental and other numerical results available in the literature indicate the validity and efficiency of the developed model.

An Anisotropic Plastic Constitutive Model for Laminate Composite Materials

이규세(Gyu-Sei Yi) 대한토목학회 2002 대한토목학회 학술대회 Vol.2002 No.11