• Journal of Mechanical Science and Technology
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• 제16권10호
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• pp.1201-1210
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• 2002

A penalty frame method is proposed for the coupled analysis of finite elements with independently modeled substructures. Although previously reported hybrid interface method by Aminpour et al (IJNME, Vol 38, 1995) is accurate and reliable, it requires non-conventional special solution algorithm such as multifrontal solver. In present study, an alternative method has been developed using penalty frame constraints, which results in positive symmetric global stiffness matrices. Thus the conventional skyline solver or band solver can be utilized in the solution routine, which makes the present method applicable in the environment of conventional finite element commercial software. Numerical examples show applicability of the present method.

• Journal of the Korean Wood Science and Technology
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• 제23권3호
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• pp.8-15
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• 1995

This analytical study was carried out to make quality and productivity up in designing the frame-type furniture with semi-rigid joint by understanding the mechanical and structural behavior of the joint and by evaluating the validity of application of the time-saving Finite Element Method to its structural analysis. Slope deflection equation for rigid joint was modified to describe the moment-rotation behavior of semi-rigid joint and the joint stiffness factor(Z) could be calculated to lessen the experimental expense. It was proved that Finite Element Analysis with imaginary elements having equivalent MOE to the semi-rigid joint could be the alternative method for the structural analysis of the frame-type furniture, comparing the internal rotation of the 2-dimensional beam-to-column model with two-pin(wooden dowel) from the finite element method with other available theoretical and experimental rotation value.

• 전기학회논문지
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• 제63권12호
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• pp.1759-1763
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• 2014

In this paper, we were performed a structural analysis and durability analysis for an integral frame with an axle according to development of the electric locomotive traction motor. In terms of the structural stability, as a result of the analysis modeling with coupling conditions of beam element and an alternative element of three-dimensional, the maximum von-Mises stress of the locking screw mounting frame were similar as 50MPa and 51MPa. Also A comparison of the natural frequency and the exciting frequency while driving of the electric locomotive No. 8200, the natural frequency is 627.05Hz~856.9Hz while the exciting frequency is not more than most 30Hz or 553Hz, 1110Hz. Therefore, it is possible to avoid the resonance.

• International Journal of Concrete Structures and Materials
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• 제10권4호
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• pp.479-497
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• 2016

Many experimental studies have evaluated the in-plane behavior of reinforced concrete frames in order to understand mechanisms that resist progressive collapse. The effects of transverse beams, frames and slabs often are neglected due to their probable complexities. In the present study, an experimental and numerical assessment is performed to investigate the effects of transverse beams on the collapse behavior of reinforced concrete frames. Tests were undertaken on a 3/10-scale reinforced concrete sub-assemblage, consisting of a double-span beam and two end columns within the frame plane connected to a transverse frame at the middle joint. The specimen was placed under a monotonic vertical load to simulate the progressive collapse of the frame. Alternative load paths, mechanism of formation and development of cracks and major resistance mechanisms were compared with a two-dimensional scaled specimen without a transverse beam. The results demonstrate a general enhancement in resistance mechanisms with a considerable emphasis on the flexural capacity of the transverse beam. Additionally, the role of the transverse beam in restraining the rotation of the middle joint was evident, which in turn leads to more ductile behavior. A macro-model was also developed to further investigate progressive collapse in three dimensions. Along with the validated numerical model, a parametric study was undertaken to investigate the effects of the removed column location and beam section details on the progressive collapse behavior.

• Structural Engineering and Mechanics
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• 제70권4호
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• pp.381-394
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• 2019

If an alternative path would not be considered for redistribution of loads, local failure in structures will be followed by a progressive collapse. When a vertical load-bearing element of a steel structure fails, the beams connected to it will lose their support. Accordingly, an increase in span's length adds to the internal forces in beams. The mentioned increasing load in beams leads to amplifying the moments there, and likewise in their corresponding connections. Since it is not possible to reinforce all the elements of the structure against this phenomenon, it seems rational to use other technics like specified strengthened connections. In this study, a novel connection is suggested to handle the stated phenomenon which is introduced as a passive connection. This connection enables the structure to tolerate the added loads after failing of the vertical element. To that end, two experimental models were constructed and thereafter tested in half-scale, one-story, double-bay, and bolted connections in three-dimensional spaces. This experimental study has been conducted to compare the ductility and strength of a frame that has ordinary rigid connections with a frame containing a novel passive connection. At last, parametric studies have been implemented to optimize the dimensions of the passive connection. Results show that the load-bearing capacity of the frame increased up to 75 percent. Also, a significant decrease in the displacement of the node wherein the column is removed was observed compared to the ordinary moment resisting frame with the same loads.

• 디지털콘텐츠학회 논문지
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• 제12권4호
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• pp.475-483
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• 2011

본 연구는 사회갈등 이슈에 대한 국내 텔레비전 보도 프레임의 매체별 차이를 살펴보는데 초점을 두고 있다. 특히 중앙의 언론과 지역의 언론 보도행태를 비교 분석하였다. 이를 위해 본 연구는 동남권 신공항 입지선정이 있었던 2011년 1월 1일부터 백지화가 발표된 2011년 4월 15일까지 보도된 KBS, MBC, SBS 전국방송과 지역방송의 저녁종합뉴스를 비교 분석하였다. 저녁종합뉴스에 대한 프레임 분석은 다시 형식적인 면과 내용적인 면으로 나누어 실시하였다. 분석결과 형식적인면에서는 전국방송과 지역방송 모두 에피소드식의 사례 나열이나 인터뷰를 중심으로 한 감정적 접근을 하는 일화적인 프레임이 주를 이루었고 주제적 프레임은 총 13건으로 7.5%에 그쳤다. 내용적인면에서는 총 174건의 보도기사를 분석한 결과 입지선정 프레임, 유치경쟁 및 대립 갈등 프레임, 경제성 프레임, 백지화 및 반응 프레임, 정부 대책 및 대안 프레임, 기타 프레임의 6개의 뉴스프레임으로 유형화되었다. 유형화된 프레임별로 뉴스보도 특성을 분석한 결과 전국과 지역방송의 보도 프레임이 확연히 구분되었다. 결국 동남권 신공항과 같은 사회갈등 이슈에 대한 매체별 접근 시각은 중앙과 지역, 방송사별 이해관계에 따라서 차이가 있음을 알 수 있다.

• 한국지구과학회지
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• 제28권6호
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• pp.645-654
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• 2007

본 연구는 지구 내부에 대한 학생들의 정신모형을 분석하고 대안개념을 조사한 것이다. 연구는 고등학교 1학년 126명의 학생들을 대상으로 그리기 과제와 면담을 병행하여 실시하였다. 연구를 수행하기 위하여 그리기 과제와 분류틀을 제작하였다. 면담과 그리기 과제의 결과물들 통하여 부호화 틀에 따라 네 단계의 인지적 모형으로 분류하였고, 대안 개념의 유형을 파악하였다. 아울러 학생들의 성별에 따른 정신모형의 관련성을 비교하였다. 연구 결과에서 대부분의 학생들은 지구 내부에 대하여 많은 대안 개념을 보였다. 분류된 정신모형은 소박한 모형이 11%, 불안정 모형이 81%, 개념적 모형이 8%로 나타났으며, 정적 정신모형으로 분류된 학생은 69%로 나타났다. 정신모형의 성별 분포에서는 유의미한 차이를 보이지 않았다.

• Steel and Composite Structures
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• 제10권1호
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• pp.1-21
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• 2010

As an alternative for conventional structures for tall buildings, a hybrid lateral load resisting structure has been designed, enabling the assembly of tall buildings directly from a truck. It consists of steel frames with discretely connected precast concrete infill panels provided with window openings. Besides the stiffening and strengthening effect of the infill panels on the frame structure, economical benefits may be derived from saving costs on materials and labour, and from reducing construction time. In order to develop design rules for this type of structure, the hybrid infilled frame has recently been subjected to experimental and numerical analyses. Ten full-scale tests were performed on one-storey, one-bay, 3 by 3 m infilled frame structures, having different window opening geometries. Subsequently, the response of the full-scale experiments was simulated with the finite element program DIANA. The finite element simulations were performed taking into account non-linear material characteristics and geometrical non-linearity. The experiments show that discretely connected precast concrete panels provided with a window opening, can significantly improve the performance of steel frames. A comparison between the full-scale experiments and simulations shows that the finite element models enable simulating the elastic and plastic behaviour of the hybrid infilled frame.

• Earthquakes and Structures
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• 제1권4호
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• pp.391-410
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• 2010

There are several important considerations that need to be made in the capacity design of RC frame-wall structures. Capacity design forces will be affected by material overstrength, higher mode effects and secondary loadpaths associated with the 3-dimensional structural response. In this paper, the main issues are identified and different means of predicting capacity design forces are reviewed. In order to ensure that RC frame-wall structures perform well it is explained that the prediction of the peak shears and moments that develop in the walls is particularly important and unfortunately very challenging. Through examination of a number of case study structures it is shown that there are a number of serious limitations with capacity design procedures included in current codes. The basis and potential of alternative capacity design procedures available in the literature is reviewed, and a new simplified capacity design possibility is proposed. Comparison with the results of 200 NLTH analyses of frame-wall structures ranging from 4 to 20 storeys suggest that the new method is able to predict wall base shears and mid-height wall moments reliably. However, efforts are also made to highlight the uncertainty with capacity design procedures and emphasise the need for future research on the subject.

• Structural Engineering and Mechanics
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• 제74권1호
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• pp.33-54
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• 2020

The aim of this study is to calculate natural frequencies and harmonic responses of cracked frames with general boundary conditions by using transfer matrix method (TMM). The TMM is a straightforward technique to obtain harmonic responses and natural frequencies of frame structures as the method is based on constructing a relationship between state vectors of two ends of structure by a chain multiplication procedure. A single variable shear deformation theory (SVSDT) is applied, as well as, Timoshenko beam theory (TBT) and Euler-Bernoulli beam theory (EBT) for comparison purposes. Firstly, free vibration analysis of intact and cracked frames are performed for different crack ratios using TMM. The crack is modelled by means of a linear rotational spring that divides frame members into segments. The results are verified by experimental data and finite element method (FEM) solutions. The harmonic response curves that represent resonant and anti-resonant frequencies directly are plotted for various crack lengths. It is seen that the TMM can be used effectively for harmonic response analysis of cracked frames as well as natural frequencies calculation. The results imply that the SVSDT is an efficient alternative for investigation of cracked frame vibrations especially with thick frame members. Moreover, EBT results can easily be obtained by ignoring shear deformation related terms from governing equation of motion of SVSDT.