http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
섬유보강 고인성 시멘트 복합체 패널의 2축 전단 비선형 모델
조창근,김윤용,Cho, Chang-Geun,Kim, Yun-Yong 한국전산구조공학회 2009 한국전산구조공학회논문집 Vol.22 No.6
본 연구에서는 철근 보강된 Engineered Cementitious Composite(ECC) 면내요소에 대한 2축응력 상태에서의 면내전단거동에 관한 예측 모델을 제시하였다. 기존의 철근콘크리트와 상이한 특성, 즉 ECC 요소의 복수미세균열 현상에 의한 높은 연성의 인장 거동, 일반 콘크리트에 비하여 연성적인 압축 연화 거동, 그리고 ECC 균열면에서의 전단전달 거동 특성 등을 모델에 반영하였다. 면내 순수전단거동에 대한 실험 및 해석결과를 통하여 개발된 R-ECC-MCFT 모델은 ECC 면내전단거동 예측에 효과적인 것으로 평가되었다. 또한 철근 보강된 ECC 면내요소는 철근콘크리트 면내요소에 비하여 최대전단강도 및 전단변형률이 증가하기 때문에 면내전단변형에서 높은 연성을 확보하는 것으로 평가되었다. The present study has been proposed a model for the in-plane shear behavior of reinforced(Engineered Cementitious Composite(ECC) panels under biaxial stress states. The model newly considers the high-ductile tensile characteristic of cracked ECC by its multiple micro-cracking mechanism, the compressive strain-softening characteristic of cracked ECC, and the shear transfer mechanism in the cracked interface of ECC element. A series of numerical analyses were performed, and the predicted curves were compared with experimental results. The proposed in-plane shear model, R-ECC-MCFT, was found to be well matched with the experimental results, and it was also demonstrated that reinforced ECC panel showed more improved in-plane shear strength and post peak behavior, in comparing with the conventional reinforced concrete panel.
조창근,임현진,이승중 한국구조물진단유지관리학회 2011 한국구조물진단학회 학술발표회논문집 Vol.2011 No.9
A nonlinear flexural model of SHCC and reinforced concrete (RC) composite slab is formulated by a fiber cross-sectional approach. The high-ductile tensile behavior of SHCC has been applied with nonlinear constitutive laws of concrete and steel bars. The prediction of the transverse nonlinear load-displacement relationship of the slab was derived by the moment-area method. The predicted responses were compared with the test results of four point bending slab test.
연결 플레이트를 사용한 프리캐스트 콘크리트 모듈러 보의 전단성능
조창근,노경민,이영학,Cho, Chang Geun,Ro, Kyong Min,Lee, Young Hak 한국공간구조학회 2021 한국공간구조학회지 Vol.21 No.4
The Precast concrete(PC) modular structures are a method of assembling pre-fabricated unit modules in the construction site. The essential aim of modular structures is to introduce a connection method that can ensure splicing performance and effectively resist shear strength. This study proposed PC module using a connecting plate that can replace splice sleeves and shear keys used in the conventional PC modular structures. To evaluate the splicing performance and shear capacity of the proposed method, the shear test was conducted by fabricating one monolithic reinforced concrete(RC) beam and two PC modular beams with a shear span-to-depth ratio as variables. The experimental results showed that the shear capacity of the PC modular beam was about 89% compared to that of the RC beam, and showed a failure of the RC beam according to the shear span-to-depth ratio. Therefore, it was considered that the connecting plate effectively transferred the stress between each PC module through the joint and ensure integrity. In addition, the applicability of shear strength equation of ACI 318-19 and Zsutty's equation to PC modular beams were evaluated. Results demonstrated that the improved shear strength equations are needed to consider reduction of shear strength in PC modules.
조창근,김일환,오칠환 ( Chang Geun Cho,Ill Hwan Kim,Chil Hwan Oh ) 대한피부과학회 1997 대한피부과학회지 Vol.35 No.5
Accessory tragi are rare congenital malformations of the external ear. They are present from birth and appear as solitary or multiple papules located between the pretragal and sternoclavicular regions. Accessory tragi may be multiple but are almost always unilateral and rarely bilateral. We report two cases of bilateral accessory tragus and a typical case of unilat,eral accessory tragus manifesting as skin-colored papules on the preauricular area. (Korean J Dermatol 1997;35(5): 980-983)
LQR 제어이득의 효율적 산정에 의한 능동텐던 구조물의 최적화
조창근,권준명,정인규,박문호,Cho, Chang-Geun,Kyun, Jun-Myong,Jung, In-Kju,Park, Moon-Ho 한국공간구조학회 2008 한국공간구조학회지 Vol.8 No.4
본 논문의 목적은, LQR 제어이득의 효율적 산정에 의한 지진하중을 받는 빌딩 구조물의 능동지진제어를 위하여 능동텐던 장치를 적용한 구조물의 지진응답제어를 위한 최적화 방법을 제시한 것이다. 텐던을 이용한 구조물 지진응답제어 문제의 정식화를 위해 Ricatti 폐회로 제어이론 및 위상보정에 의한 시간지연현상을 도입하였으며, 상태방정식의 해를 산정하기 위해 전달 행렬을 이용한 수치해석법을 이용 사다리꼴적분법에 의해 상태벡터의 해를 산정하였다. 성능지수의 최적화를 위해, 최소 가중행렬비를 설계변수로, IBC 2000의 허용층간변위 규정과 텐던의 최대제어력을 제약조건으로 하여, SUMT 기법에 의해 최적 해를 산정토록 최적제어 프로그램을 개발하였다. 8층 빌딩구조물에 대한 적용 예에서, 최적제어를 적용한 시스템이 비제어 시스템에 비해 층간제어효과가 우수하고, 일정 가중행렬비 적용 제어시스템에 비해 낮은 성능지수가 요구되었다. The objective of current study is to develop an optimization technique for the seismic actively controlled building structures using active tendon devices by an efficient solution of LQR control gain. In order to solve the active control system, the Ricatti closed-loop algorithm has been applied, and the state vector has been formulated by the transfer matrix and solved by a numerical technique of the trapezoidal rule. The time-delay problem has been also considered by phase compensation. To optimize the performance index, the ratio of the weighted matrix is the design variable, allowable story drift limits of IBC 2000 and tendon forces have been applied as restraint conditions, and the optimum control program has been developed with the algorithm of the SUMT technique. In examples of the optimization problem of eight stories shear buildings, it is evaluated that the optimum controlled building is more suitable in the control of earthquake response than the uncontrolled system and can reduce the performance index to compare with the controlled system with a constant ratio of the weighted matrix.
조창근,김윤용,서정환,이승중,Cho, Chang-Geun,Kim, Yun-Yong,Seo, Jeong-Hwan,Lee, Seung-Jung 한국공간구조학회 2012 한국공간구조학회지 Vol.12 No.1
압출성형 ECC 패널을 활용한 철근콘크리트 복합 슬래브 구조에 대한 비선형 휨 해석 모델을 새롭게 제시하였다. ECC 패널은 직접인장시험 결과로부터 균열 이후에 고인성 인장거동을 하는 재료로 모델링하였다. 개발 모델을 기존 철근콘크리트 슬래브 및 ECC 패널 철근콘크리트 복합슬래브 실험체의 휨 실험결과와 비교하였다. 예측결과는 실험결과와 잘 일치하였으며, ECC 패널 적용 철근콘크리트 복합슬래브는 균열제어, 휨내력 및 휨변형능력 개선에 장점이 있는 것으로 판단되었다. A model for the nonlinear flexural analysis of extruded Engineered Cementitious Composite (ECC) panel reinforced concrete (RC) composite slab has been newly presented. From direct tensile test, ECC panel has been modeled to have the high-ductile tensile behavior after cracking. The developed model was compared with bending test results of two specimens, a conventional RC slab and a ECC panel RC composite slab. The predicted results were well patched with the experimental results, and the ECC panel RC composite slab system had advantages in crack control and improving flexural load-carrying capacity and deformation-capacity.
SP제 및 물시멘트비에 따른 유동 콘크리트의 레올로지 및 유동특성 실험
조창근(Cho Chang-Geun),최열(Choi Yeol),김화중(Kim Wha-Jung) 대한건축학회 2008 대한건축학회 학술발표대회 논문집 - 계획계/구조계 Vol.28 No.1(구조계)
In the current study, rheological and flow characteristics of flowable concrete manufactured in domestic products of cement, aggregates, and SP admixtures were investigated by experimental programs varying with mix proportions. By experiment, it was known that rheological characteristics of flowable concrete were effected by the water-cement ratio, aggregates, and the dosage of SP admixture. By flow tests such slump, L-box, Y-box, and U-box tests, flow characteristics were also effected by mix proportions varying with the water-cement ratio and the dosage of SP admixture. The experimental data collected by the present study will be used as basic data in order to model the rheological parameters and to simulate the flow of flowable concrete considering with mix proportions.
조창근 ( Chang Geun Cho ),홍승현 ( Seung Hyun Hong ),이길주 ( Gil Ju Yi ),송해준 ( Hae Jun Song ),오칠환 ( Chil Hwan Oh ) 대한피부과학회 1998 대한피부과학회지 Vol.36 No.1
A umbilical omphalomesenteric duct polyp is the result of incomplete closure of the omphalomesenteric duct, which connects the midgut with the yolk sac of the embryo. It may be associated with underlying embryologic anomalies such as Meckels diverticulum and umbilical enteric fistula, the complications of which may at times be fatal. This rare malformation should be clinically discerned from persistent granulation tissue or pyogenic granuloma. Histologically, it shows a polypoid lesion consisting of ectopic gastrointestinal epithelium with the appearance of gastric, intestinal, or colonic mucosa. We report a case of an umbilical omphalomesenteric duct polyp in an 8-year-old male patient, who had had a bright-red polyp on the umbilicus from the age of 1 month and had not had any other types of underlying abnormalities. (Korean J Dermatol 1998;36(1): 107-110)