• Structural Engineering and Mechanics
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• 제81권4호
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• pp.395-409
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• 2022

The presence of infill generally neglected in design despite the fact that infill contribution significantly increase the lateral stiffness and strength of the reinforced concrete frame structure. Several experimental studies and computational models have been proposed to capture the rational response of infill-frame interaction at global level. However, limited studies are available on explicit finite element modelling to study the local behavior due to high computation and convergence issues in numerical modelling. In the current study, the computational modelling of RC frames is done with various configurations of infill masonry in terms of types of blocks, lateral loading and reinforcement detailing employed with material nonlinearities, interface contact issues and bond-slip phenomenon particularly near the beam-column joints. To this end, extensive computational modelling of five variant characteristics test specimens extracted from the detailed experimental program available in literature and process through nonlinear static analysis in FEM code, ATENA generally used to capture the nonlinear response of reinforced concrete structures. Results are presented in terms of damage patterns and capacity curves by employing the finest possible detail provided in the experimental program. Comparative analysis shows that good correlation amongst the experimental and numerical simulated results both in terms of capacity and crack patterns.

• Coupled systems mechanics
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• 제12권5호
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• pp.461-479
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• 2023

The paper deals with the finite element modelling of the free vibration and structural behavior of a particular four-floor reinforced concrete structure subjected to static equivalent seismic loads and supported by a shallow foundation system called SNSF (Spider Net System Footing). The two FE models are a simple 2D Matlab model and a detailed 3D model based on solid elastic elements using Altairworks (Hypermesh and Optistruct). Both models can simulate the soil structure interaction. We concentrate on the behavior of a representative cell involving two columns on five levels. The influence of the boundary conditions on the external vertical planes of the domain are duly studied. The Matlab model appears relevant for a primary estimation of frequencies and stiffness of the whole structure under vertical and lateral loads.

• Structural Engineering and Mechanics
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• 제62권5호
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• pp.643-649
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• 2017

Masonry walls are amongst the oldest building systems. A large portion of the research on these structures focuses on the load-bearing walls. Numerical methods have been generally used in modelling load-bearing walls during recent years. In this context, macro and micro modelling techniques emerge as widely accepted techniques. Micro modelling is used to investigate the local behaviour of load-bearing walls in detail whereas macro modelling is used to investigate the general behaviour of masonry buildings. The main objective of this study is to investigate the elastic behaviour of the load- bearing walls in masonry buildings by using micro modelling technique. In order to do this the brick and mortar units of the masonry walls are modelled by the combination of plane truss elements and plane frame elements with no shear deformations. The model used in this study has fewer unknowns then the models encountered in the references. In this study the vertical frame elements have equivalent elasticity modulus and moment of inertia which are calculated by the developed software. Under in-plane static loads the elastic displacements of the masonry walls, which are encountered in literature, are calculated by the developed software, where brick units are modelled by plane frame elements, horizontal joints are modelled by vertical frame elements and vertical joints are modelled by horizontal plane truss elements. The calculated results are compatible with those given in the references.

• Advances in Computational Design
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• 제7권3호
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• pp.173-188
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• 2022

In modern buildings, glass is considered a structurally unsafe material due to its brittleness and unpredictable failure behavior. The possible use of structural glass elements (i.e., floors, beams and columns) is generally prevented by its poor tensile strength and a frequent occurrence of brittle failures. In this study an innovative modelling based on an equivalent thickness concept of laminated glass beam reinforced with FRP (Fiber Reinforced Polymer) composite material and of glass plates punched is presented. In particular, the novel numerical modelling applied to an embedding Carbon FRP-rod in the interlayer of a laminated structural glass beam is considered in order to increase both its failure strength, together with its post-failure strength and ductility. The proposed equivalent modelling of different specimens enables us to carefully evaluate the effects of this reinforcement. Both the responses of the reinforced beam and un-reinforced one are evaluated, and the corresponding results are compared and discussed. A novel equivalent modelling for reinforced glass beams using FRP composites is presented for FEM analyses in modern material components and proved estimations of the expected performance are provided. Moreover, the new suggested numerical analysis is also applied to laminated glass plates with wide holes at both ends for the technological reasons necessary to connect a glass beam to a structure. Obtained results are compared with an integer specimen. Experimental considerations are reported.

• 터널과지하공간
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• 제31권5호
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• pp.309-332
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• 2021

고준위방사성폐기물 심층처분장 내 천연방벽은 방사성핵종의 누출을 방지 및 지연할 수 있는 수리학적 특성을 갖춰야 한다. 결정질 암반의 경우 불연속면에 의해 수리학적 성능이 결정되기 때문에, 불연속면의 수리-역학적 복합거동에 대한 자세한 모사가 필요하다. 불연속체 기반 해석기법은 불연속면의 생성, 전파, 변형, 미끄러짐과 같은 복잡한 거동을 구현할 수 있어 결정질 암반 모사에 적합하다. 본 연구에서는 불연속면에서의 수리-역학 복합거동에 초점을 맞추어, UDEC, 3DEC, PFC, DDA, FRACOD, TOUGH-UDEC과 같은 상용화된 불연속체 기반 수리-역학 복합거동 해석기법을 조사하였다. 블록 기반 불연속체 해석기법의 경우 주로 불연속면 상에서 진행되는 유체 유동을 바탕으로 수리-역학 복합거동을 해석하였고, 그중 일부는 다른 수리학적 해석기법과의 결합을 통하여 모델 전체에 대한 수리-역학적 복합거동을 제공하였다. 입자 기반 불연속체 해석기법의 경우에는 입자 사이로 흐르는 유체를 반영하여 불연속체 모델 전체에 해당하는 수리-역학적 복합거동 모사가 가능하다. 현재까지 상용화된 불연속체 기반 복합거동 해석기법은 2차원 해석만 제공하거나, 수리학적 해석 성능이 떨어지고, 불연속면에서의 유체 유동만 고려되거나, 자세한 수리학적 해석을 지원하지 않는 등의 한계점이 있어 고준위방사성폐기물 심층처분시스템의 정확한 수리-역학 모델링에는 적합하지 않을 수 있다. 본 기술보고에서 검토한 다양한 해석기법들의 장단점을 참고하여 향후 처분시스템을 정확하고 자세하게 모사할 수 있는 불연속체 기반 수리-역학 복합거동 해석기법의 개발이 필요하다.

• 한국지반공학회논문집
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• 제22권10호
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• pp.111-120
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• 2006

본 연구에서는 개별요소해석 프로그램 PFC를 이용하여 실내 대형삼축압축시험에 대한 거동예측 및 실내시험 결과와의 분석을 수행하였다. 댐 축조용 락필재료(rockfill material)에 대한 실내 대형삼축압축시험을 수행하였으며, PFC 해석에 있어서는 초기 간극률을 고려한 개별요소 생성과 팽창, clump logic을 이용한 대상재료의 입도분포 모델링을 수행하였다. 특정 구속압 조건에 대한 실내시험 결과를 이용하여 개별요소해석시 필요한 미시 물성치(micro Parameter)를 산정하였으며, 이를 이용하여 다양한 응력조건에 대한 개별요소해석을 수행하였다. 본 연구결과, 개별요소법은 지반공학적 측면에서, 조립재료에 대한 미시적 거동(micro behavior) 및 전체적 거동(macro behavior)의 예측뿐 아니라, 수치시험실(numerical laboratory)로서 활용될 수 있음을 확인할 수 있었다.

• 한국기계가공학회지
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• 제18권10호
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• pp.75-82
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• 2019

Few studies have been conducted regarding theoretical turning force modelling while considering cutting constant. In this paper, a new cutting force modelling technique was suggested which considers the specific cutting force coefficients for turning. The specific cutting force is the multiplication of the cutting force coefficient and uncut chip thickness. This parameter was used for experimental modelling and prediction of theoretical cutting force. These coefficients, which can be obtained by fitting measured average forces in several conditions, were used for the formulation of three theoretical cutting forces for turning. The cutting force mechanism was verified in this research and its results were compared with each of the experimental and theoretical forces. The deviation of force was incurred by a small amount in this model and the predicted force considering feed rate, nose radius, and radial depth shows a physical behavior in main force, normal force, and feeding force, respectively. Therefore, this modelling technique can be used to effectively predict three turning forces with different tool geometries considering cutting force coefficients.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1995년도 춘계학술대회논문집
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• pp.107-113
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• 1995

To investigate the behavior of platic deformation inaxisymmetric hot extrusion through square dies, the physical modelling with the plasticine as a model material is carried out at the room temperature. Some mechanical properties of the model material are determined by compression and ring compression tests. Visioplasticity method using experimetal grid distortion is introduced to anlayze the plastic flow, strain rate and strain distribution.

• 한국지반신소재학회논문집
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• 제10권4호
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• pp.105-112
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• 2011

본 논문에서는 지속하중이 작용하는 보강토 구조물의 시간의존적 장기거동에 관한 수치 모델링 기법을 다루었다. 먼저 Power Law 기반의 크리프 모델을 이용하여 지오그리드와 뒤채움흙의 크리프 거동의 모델링에 대한 적용성을 검토 하였으며 나아가 보강토 교대 구조물의 장기 거동에 대한 해석에 적용하였다. 그 결과 Power Law 기반의 크리프 모델은 지오그리드와 뒤채움흙으로 구성되는 보강토 교대 구조물에 지속하중 작용시 발생하는 크리프 변형을 적절히 모사할 수 있는 것으로 검토되었으며 크리프 변형이 발생할 수 있는 뒤채움흙을 사용하는 경우 교대 벽체 및 상판기초에 허용치를 초과하는 변위가 발생할 수 있는 것으로 검토되었다. 본 연구에서 얻어진 결과의 실무적 적용 방안에 대한 내용을 기술하였다.

• Steel and Composite Structures
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• 제18권5호
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• pp.1215-1237
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• 2015

The majority of connections in moment resisting frames are considered as being fully-rigid. Consequently, the real behavior of the connection, which has some level of flexibility, is ignored. This may result in inaccurate predictions of structural response. This study investigates the influence of flexibility of the extended end-plate connections in the steel moment frames. This is done at two levels. First, the actual micro-behavior of extended end-plate moment connections is explored with respect to joint flexibility. Then, the macro-behavior of frames with end-plate moment connections is investigated using modal, nonlinear static pushover and incremental dynamic analyses. In all models, the P-Delta effects along with material and geometrical nonlinearities were included in the analyses. Results revealed considerable differences between the behavior of the structural frame with connections modeled as fully-rigid versus those when flexibility was incorporated, specifically difference occurred in the natural periods, strength, and maximum inter-story drift angle.