• Title/Summary/Keyword: 변형 능력

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Effect of Aspect Ratio and Diagonal Reinforcement on Shear Performance of Concrete Coupling Beams Reinforced with High-Strength Steel Bars (세장비 및 대각철근 유무에 따른 고강도 철근보강 콘크리트 연결보의 전단성능)

  • Kim, Sun-Woo;Jang, Seok-Joon;Yun, Hyun-Do;Seo, Soo-Yeon;Chun, Young-Soo
    • Journal of the Korea Concrete Institute
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    • v.29 no.1
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    • pp.43-51
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    • 2017
  • As per current seismic design codes, diagonally reinforced coupling beams are restricted to coupling beams having aspect ratio below 4. However, a grouped diagonally reinforcement detail makes distribution of steel bars in the beam much harder, furthermore it may result in poor construction quality. This paper describes the experimental results of concrete coupling beam reinforced with high-strength steel bars (SD500 & SD600 grades). In order to improve workability for fabricating coupling beams, a headed large diameter steel bar was used in this study. Two full-scale coupling beams were fabricated and tested with variables of reinforcement details and aspect ratio. To reflect real behavior characteristic of the beam coupling shear walls, a rigid steel frame system with linked joints was set on the reaction floor. As a test result, it was noted that cracking and yielding of reinforcement were initially progressed at the coupling beam-to-shear wall joint, and were progressed to the mid-span of the coupling beam, based on the steel strain and failure modes. It was found that the coupling beams have sufficient deformation capacity for drift ratio of shear wall corresponding to the design displacement in FEMA 450-1. In this study, the headed horizontal steel bar was also efficient for coupling beams to exhibit shear performance required by seismic design codes. For detailed design for coupling beam reinforced with high-strength steel, however, research about the effect of variable aspect ratios on the structural behavior of coupling beam is suggested.

Behavioral Characteristics and Energy Dissipation Capacity of Short Coupling Beams with Various Reinforcement Layouts (다양한 배근상세를 갖는 짧은 연결보의 주기거동 특성과 에너지소산능력의 평가)

  • Eom, Tae-Sung;Park, Hong-Gun;Kang, Su-Min
    • Journal of the Korea Concrete Institute
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    • v.20 no.2
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    • pp.203-212
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    • 2008
  • The cyclic behavior and energy dissipation mechanism of short coupling beams with various reinforcement layouts were studied. For numerical analysis of coupling beams, nonlinear truss model was used. The results of numerical analysis showed that the coupling beams with conventional reinforcement layout showed pinched cyclic behavior without significant energy dissipation, whereas the coupling beams with diagonal reinforcement exhibited stable cyclic behavior without pinching. The energy dissipation of the coupling beams was developed mainly by diagonal reinforcing bars developing large plastic strains rather than concrete which is a brittle material Based on this result, simplified equations for evaluating the energy dissipation of coupling beams were developed. For verification, the predicted energy dissipation was compared with the test results. The results showed that the simplified equations can predict the energy dissipation of short coupling beams with shear span-to-depth ratio less than 1.25 with reasonable precision, addressing various design parameters such as reinforcement layout, shear span-to-depth ratio, and the magnitude of inelastic displacement. The proposed energy equations can be easily applied to performance-based seismic evaluation and design of reinforced concrete structures and members.

The Asian mode of production of Japanese Manga Higajima -The protests of the Political Structure and Asian mode of production (일본 만화 <피안도(彼岸島(Higajima))>와 아시아적 생산 양식 아시아적 생산양식의 정치구조와 투쟁)

  • Lee, Ho-Young
    • Cartoon and Animation Studies
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    • s.25
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    • pp.109-132
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    • 2011
  • The Vampire has relatively universal images in through the cultural and verbal usages. The comic Higajima and movie display the latest image of Japanese Vampire of asian mode of production. After the Meiji political reformation of 18th Century, Japanese had rapidly changed into European style in every places. However, the Higajima is denied the structural changes, it is insisted that the changing is only the skin deep and colour of hair but the structure of the society is same as feudal Japan. Asian mode of production is claimed by Karl Marx, according to him, it is before the historical developing model in Europe and it was controversial. The major character of modern Japanese history would be the change of hierarchy of king-shogun-samurai-peasant based on the regional ground. The feudal structure is changed by the Meiji reformation and Japan was rushed for the westernized country rather than the asian mode of production. However, Higajima argued that the changing is just the clothes of ruler but the democracy and individual citizenship was lost in that reformation. Vampire is cursed creature that cannot see the sun and it has not the functioned as a human organ. For human it is dead but this creature actively moves and stronger than human and much superior than human in every aspects. It is managed the feeding through the suck the human blood and power to seduction. Even it is not exist, it is quite symbolic phenomenon of cultural usage of superior entity of chain of feeding. The aim of this paper is display the symbolic code Vampire of Asian mode of production in Higajima and political struggling of Japan in actual. To search of the cultural meaning and possibility of the Korean solution of modernity.

Axial Compression of Stub Columns for Concrete-filled Square Steel Tubes (일축 압축력을 받는 콘크리트충전 각형강관 단주의 구조적 거동)

  • Yoo, Yeong-Chan
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.22 no.2
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    • pp.617-624
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    • 2021
  • Concrete-filled steel tubular columns can improve the strength and deformation capacity of structures, thereby enabling the development of efficient structures. The Korean design standard (KDS41) regarding concrete-filled steel tubular structures, established by the architectural institute of Korea in 2005, was revised in 2009 and 2016. The objective was to understand the compressive strengths and deformation capacity of stub columns for concrete-filled square steel tubes under uniaxial compression and validate the KDS41's standard code for necessary corrections. Experiments were conducted on 26 specimens with parameters, such as the width-thickness ratio of cold-formed square tubes. The following values of the stub columns for concrete-filled square steel tubes were obtained: compressive strengths, relationship between the axial load and axial displacement, and failure modes. An analysis of these results enabled an understanding of the concrete-filled effect and the influence of the wide-thickness ratio. The compressive strengths of filled concrete saw a 9% increase compared to a state of uniaxial stress, which must be noted in a future edition of KDS41. After benchmarking the results regarding square steel tubes generated by cold forming to the guidelines provided by the KDS41, the KDS41's value of 2.26 for the limiting width-to-thickness ratio for the compact section was found to be inflated. With a safety concern, this paper proposes a more conservative value of 1.35.

Evaluation of Deformation Capacity of Various Steel Springs Subjected to Tensile Loading or Uniaxial Cyclic Loading (인장하중 및 반복하중을 받는 강재 스프링의 변형 성능 평가)

  • Kwon, Hee-Yong;Hwang, Seung-Hyeon;Yang, Keun-Hyeok;Kim, Sanghee;Choi, Yong-Soo
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.26 no.4
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    • pp.1-10
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    • 2022
  • In this study, to evaluate the possibility of using a steel spring as a displacement-dependent damping device, tensile loading and cyclic loading tests were performed. The main experimental variables were the type of steel (SAE9254 and SS275), the spring constant (700 N/mm, 1,000 N/mm, and 1,400 N/mm), and the presence or absence of heat treatment for SAE9254. As a result of the tensile test, the ratios of the measured spring constant to the design spring constant of the steel springs made with SAE9254 ranged from 1.08 to 1.13, while the ratios of the design spring constant and the measured spring constant of the steel springs made with SS275 ranged from 0.86 to 0.97. After yielding, the slope values of the load-displacement curve of the SAE9254 with/without heat treatment were about 240~251 N/mm and 92 N/mm, respectively, but the slope values of the load-displacement response of SS275 were almost zero. According to the uniaxial cyclic loading test results, all specimens were satisfied with three conditions for a displacement-dependent damping device in KDS 41 17 00 (2019): the maximum force and minimum force at zero displacement, the maximum force and minimum force at the maximum displacement, and the energy dissipation capacity. In addition, the equivalent damping ratios of steel springs made with SAE9254(non-heat treatment) and SS275 were approximately 2.8 times and 1.9 times greater, respectively, than that of steel springs made with SAE9254.

Bending Performances and Collapse Mechanisms of Light-weight Aluminum-GERP Hybrid Square Tube Beams (경량화 알루미늄-GFRP 혼성 사각관 보의 굽힘성능 및 붕괴 메커니즘)

  • Lee, Sung-Hyuk;Kim, Hyung-Jin;Chang, Young-Wook;Choi, Nak-Sam
    • Composites Research
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    • v.20 no.3
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    • pp.8-16
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    • 2007
  • Bending collapse of light-weight square tubes used for vehicle structure components is a dominant failure mode in oblique collision and rollover of vehicles. In this paper bending performances of aluminum-GFRP hybrid tube beams were evaluated in relation with bending deformation behavior and energy absorption characteristics. Aluminum/GFRP hybrid tube beams fabricated by inserting adhesive film between prepreg and metal layer were used in the bending test. Failure mechanisms of hybrid tubes under a bending load were experimentally investigated to analyze the bending performance as a function of ply orientation and composite layer thickness. Ultimate bending moments and energy absorption capacity of hybrid tube beams were obtained from the measured load-displacement corves. It was found that aluminum/GFRP hybrid tubes could be converted to rather stable collapse mode showing excellent energy absorption capacity in comparison to the pure aluminum tube beams. In particular, the hybrid tube beam with $[0^{\circ}/90^{\circ}]s$ composite layer showed a large improvement by about 78% in energy absorption capacity and by 29% in specific energy absorption.

창의성과 비판적 사고

  • Kim, Yeong Jeong
    • Korean Journal of Cognitive Science
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    • v.13 no.4
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    • pp.80-80
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    • 2002
  • The main thesis of this article is that the decisive point of creativity education is the cultivation of critical thinking capability. Although the narrow conception of creativity as divergent thinking is not subsumed under that of critical thinking, the role of divergent thinking is not so crucial in the science context of creative problem-solving. On the contrary, the broad conception of creativity as focusing on the reference to utility and the third conception of creativity as a process based on the variation and combination of existing pieces of information are crucial in creative problem-solving context, which are yet subsumed under that of critical thinking. The emphasis on critical thinking education is connected with the characteristics of contemporary knowledge-based society. This rapidly changing society requires situation-adaptive or situation-sensitive cognitive ability, whose core is critical thinking capability. Hence, the education of critical thinking is to be centered on the learning of blowing-how and procedural knowledge but not of knowing-that and declarative knowledge. Accordingly, the learning of critical thinking is to be headed towards the cultivation of competence but not just of performance. In conclusion, when a rational problem-solving through critical and logical thinking turns out consequently to be novel, we call it creative thinking. So, creativity is an emergent property based on critical and logical thinking.

창의성과 비판적 사고

  • 김영정
    • Korean Journal of Cognitive Science
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    • v.13 no.4
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    • pp.81-90
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    • 2002
  • The main thesis of this article is that the decisive point of creativity education is the cultivation of critical thinking capability. Although the narrow conception of creativity as divergent thinking is not subsumed under that of critical thinking, the role of divergent thinking is not so crucial in the science context of creative problem-solving. On the contrary, the broad conception of creativity as focusing on the reference to utility and the third conception of creativity as a process based on the variation and combination of existing pieces of information are crucial in creative problem-solving context, which are yet subsumed under that of critical thinking. The emphasis on critical thinking education is connected with the characteristics of contemporary knowledge-based society. This rapidly changing society requires situation-adaptive or situation-sensitive cognitive ability, whose core is critical thinking capability. Hence, the education of critical thinking is to be centered on the learning of blowing-how and procedural knowledge but not of knowing-that and declarative knowledge. Accordingly, the learning of critical thinking is to be headed towards the cultivation of competence but not just of performance. In conclusion, when a rational problem-solving through critical and logical thinking turns out consequently to be novel, we call it creative thinking. So, creativity is an emergent property based on critical and logical thinking.

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Developing a Convergent Class Model of Augmented Reality and Art (증강현실과 예술의 융복합 수업모형 개발)

  • Pi, Su-Young;Lee, Myung-Suk
    • Journal of Digital Convergence
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    • v.14 no.5
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    • pp.85-93
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    • 2016
  • Convergent education is essential to develop consilient thinking skills, ability to recreate information and knowledge, and problem-solving skills which are demanded in society of convergent knowledge. Accordingly, this study is going to develop a convergent class model of augmented reality and art based on consilient knowledge. Teaching model is designed based on the ADDIE model, which was operated by opening a real class in order to verify the validity. The result showed a high satisfaction of learners showed the ability to adapt to the major areas associated with the cultivation of learners. Characteristics of augmented reality medium were found to enable learners to analyze a new phenomenon and to fuse the necessary knowledge by inducing them to actively interact by the their intention in learning. Therefore, it is possible to cultivate creative and convergent persons of ability equipped with more flexible and creative thinking ability and discernment through deepened education for recognizing and understanding convergent cases between art and scientific technology. There is a study on the validation and the convergence of different subjects in terms of a variety of aspects, left behind of this study.

A Balanced Panel Zone Strength Criterion for Reduced Beam Section Steel Moment Connections (보 플랜지 절취형 (RBS) 철골 모멘트 접합부의 균형패널존 강도)

  • Lee, Cheol Ho;Kim, Jae Hoon;Jeon, Sang Woo;Kim, Jin Ho
    • Journal of Korean Society of Steel Construction
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    • v.18 no.1
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    • pp.59-69
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    • 2006
  • This paper presents test results on reduced beam section (RBS)program addressed panel zone (PZ) strength as the key variables. PZ strength has been much debated issue for several decades. A desirable range of PZ strength has not yet been proposed despite the fact that a significant amount of RBS test data is available. Test results from this study and by others showed that panel zones could easily develop a plastic rotation of 0.01 radian without causing distress to the beam flange groove welds. At this deformation level, the amount of beam distortion (i.e., buckling) was about one half that developed in strong PZ specimens. A criterion for a balanced PZ strength that improves the plastic rotation capacity while reducing the amount of beam buckling is proposed.