수화열에 의한 매스콘크리트 박스 라멘 구조물의 구조거동 연구

조병완,이계삼,고상윤 한국구조물진단유지관리학회 2000 한국구조물진단학회 학술발표회논문집 Vol.- No.-

물리적 방법에 의한 나노시멘트 제조

조병완,박종빈,최해윤,박진모 한국시멘트협회 2004 시멘트 심포지움 Vol.31 No.-

내압을 받는 복합 적층 파이프(GFRP) 구조의 유한요소 해석

조병완 한국전산구조공학회 1994 한국전산구조공학회논문집 Vol.7 No.2

내압을 받는 섬유강화 복합적층 파이프 구조를 해석하기 우해 감절점 원통형 쉘 유한요소를 이용하였다. 이요소는 lockintg현상을 제거하고, 수렴성을 개선하기 위해 감차적분기법, 변위형의 추가, 가정된 전단 변형 도장을 사용한 9절점의 3차원 쉘 유한요소이다. 이 유한요소를 이용하여 여러개의 예제를 해석하고, 결과를 이론식 및 다른 구조해석 프로그램과 비교하였다. 비교결과 유한요소의 수렴도 양호하였고, 섬유강과 복합적층 파이프 구조의 섬유 배향 각도를 증가시킴에 따라 파이프의 처짐은 감소하면서 파이프의 강성이 증가함을 알 수 있고 이는 또한 90.deg.적층 각도가 내압을 받는 파이프 구조의 hoop tension을 유효하게 받을 수 있음을 보여주고 있다. A degenerated cylindrical shell element for modeling glass fiber reinforced plastic pipes is developed and its performance for static structural analysis under internal uniform pressure is evaluated. The element is a nine node degenerated solid shell element with reduced integration technique, addition of nonconforming displacement modes, and assumed strain method to improve convergence of analysis. Several numerical examples are solved and compared with analytical solutions and other F.E.M programs, The results show that the increment of fiber orientation in the GFRP pipes with reference to the longitudinal axis cause less radial displacements and much stiffness in the pipes. This is reasonable since the internal pressure will primarily cause hoop stresses in the ring and 90-angle ply GFRP ring carry these efficiently in pure tension.

Modal-Perturbation 기법을 이용한 항만 구조물의 손상부위 추정

조병완,한상주 한국전산구조공학회 1996 한국전산구조공학회논문집 Vol.9 No.4

구조물의 손상전후에 나타나는 고유진동수와 모드 형상으로 부터 Inverse Modal Perturbation기법을 이용하여 잔교식 부두나 돌핀과 같은 대규모 항만구조물의 손상도 추정을 위한 모드 기여도 계수를 근사적으로 직접 구하는 방법을 제시하였다. 잔교식 항만구조물의 고유치 해석을 통해 구조물의 강성 변화량과 구조물의 고유진동수와 모드 형상의 변화량과 요소 손상도 계수를 도입하여 Inverse Modal Perturbation의 2차항을 고려한 관계식을 유도하고 손상전후에 구조물의 강성 감소로 나타나는 구조물의 손상도를 추정하여 수렴정도를 고찰하였다. An Inverse modal perturbation method was applied to estimate the assessments of the damages at the large-scaled marine structure, such as pier or dolphin, from the structural dynamic natural frequencies and mode shape. Vibrations of structural stiffness, natural frequencies and mode shapes from the eigenvalue analysis lead to the modal peturbation equations, which were considered with a second order term. This paper estimates the assessments of the damages for the structure with the decreased stiffness and shows the convergence of perturbation equation.

온도변화에 의한 콘크리트 포장도로의 구조 거동 연구

조병완 한국전산구조공학회 1991 한국전산구조공학회논문집 Vol.4 No.2

콘크리트 포장도로의 일부구간에서 보이고 있는 심각한 균열파괴 현상은 주하중인 차량하중 외에 환경요소 인 온도변화의 영향으로, 콘크리트 슬래브 상, 하면의 온도차이에 따라 위, 아래방향으로 오목하게 휘면서, 기 초지반과 떨어지는 슬래브의 중앙 또는 줄눈부에 차량하중이 재하되어 발생된다. 이로 인하여 콘크리브 슬래브에 종적, 형적 균열이 발생하여 Faulting, Ravelling, Spalling, sca피19 ... 동 파괴 현상이 심회되고 있다. 따라서 본 연구에서는 유한요소볍올 이용한 강성행렬과 온도변화, 건조수축 둥으로 인한 퉁가절정하 중올 유도하여 전국 여러지방의 온도변화 특성에 따른 역학적 거동현상을 연구하였다. Some sections of concrete highway pavements have been viewed with great concern by highway off icials and engineers due to the severe cracking and failure problems. This is mainly due to the traffic loads in addition to temperature variations between top and bottom of concrete slab, which cause the concrete slab to curl up and down depending on the thermal gradient, respectively. Subsequently, a major consideration was given to the derivation of stiffness matrix and equivalent nodal loads due to the uniform gravity load, temperature and shrinkage of concrete. And the structural behavior of concrete highway pavement due to the temperature variations throughout the nations has been emphasized.

Micro Crack Propagatin Behavior of Concrete with the Lattice Model

조병완,Ghi Ho Tae,Chang Hyun Kim 대한토목학회 2005 KSCE JOURNAL OF CIVIL ENGINEERING Vol.9 No.4

This paper discusses 2D lattice models of beams for simulating the fracture of brittle materials. A simulation of an experiment on aconcrete beam subjected to bending, in which two overlapping cracks occur, is used to study the effect of individual beamcharacteristics and diferent arrangements of the beams in the overall lattice. It was found that any regular orientation of the beamsinfluences the resulting crack patterns. Methods to implement a wide range of poisson's ratios are also developed, the use of thelattice to study arbitrary micro-structures is outlined. The crack pattern that are obtained with lattice are in good agreement with thedimensions were measured on the predicted lattice damage patterns.

Wind Characteristics of Existing Long Span Braidge Base on Measured Date

조병완,Jong Chil Park,Chang Hyun Kim 대한토목학회 2005 KSCE JOURNAL OF CIVIL ENGINEERING Vol.9 No.3

This paper presents the wind characteristics of an existing long span bridge based on the measured wind data. The wind data obtained from the two measuring stations on the Seohae bridge are processed and statistically analyzed. The Weibull distribution is used to model the wind speed on the bridge. The parameters of the Weibull distribution, k and c are estimated using two methods, the regression method and the Chi-Square method. To examine the fits of two methods, the Kolmogorov-Smirnov test is used. It is found that the two methods give a good fit to the distribution of the measured wind speed data on the bridge. The dominant wind directions on the FCM bridge are northwest and east. The wind rose diagram shows that strong winds usually come from the northwest. From the Weibull distribution for each direction, it can be known that the parameters of k and c are quite different according to the wind direction.

Celay System을 이용한 In-Ceram Alumina 3 Unit Bridge제작법

조병완,Jo, Byung-Woan 대한심미치과학회 1996 Journal of the Korean Academy of Esthetic Dentistr Vol.5 No.1

In nowdays many dental CAD/CAM system were developed. Among those only Cerec and Celay were used globally as clinical application. Celay is a machinable ceramic system that is capable of milling inlays, onlays, and veneers from prefabricated industrial ceramic blocks(Vita Celay Blanks). The advatages of Celay are to simplify the manufactures and to save the processing time. For esthetics In-Ceram Alumina bridges were introduced into maxillary anterior restoration. They have a high strength, a high translucency and an excellent marginal adapation. But the laboratory processes are very difficult and complicated. So the construction of In-Ceram Alumina bridge combined with celay system was desgined. The patient is a 28 year old age male. The chief complain is missing of maxillary left central incisor. He wants to restore anterior bridge for esthetically. The Alumina bridge framework was constructed easily by celay system. Glass ilfiltration was occurred. After that, vitadura-${\alpha}$porcelain build up was occurred by conventional method. The translucency of In-Ceram Alumina 3 unit bridge revealed to be superior to that of porcelain fused to metal bridge. So we report it with clincal case and literature reviews.

팽창제를 이용한 지하 PC콘크리트 박스구조물의 성능개선 연구

조병완 한국시멘트협회 2001 시멘트 Vol.154 No.-

In-Ceram Spinell Crown의 제작법과 임상적 응용

조병완,Jo, Byung-Woan 대한심미치과학회 1997 Journal of the Korean Academy of Esthetic Dentistr Vol.6 No.1

By the concerns of esthetic restoration were increased recently. many all ceramic crowns were developed. But they except In-Ceram Alumina were used only single crown. In-Ceram Alumina, developed by Dr. Sadon, was revealed to have high flexural Strength(450MPa). So it could be used not only anterior bridges but also posterior bridges. But In-Ceram Alumina was seen to be opaque, a little green color in transillumination light by high content of alumina oxide(85%). So new all ceramics with high strength and high translucence were needed. Spinell($MgAl_2O_3$) have a high melting point, high flexural strength, low heat conductivity, high light conductivity. In-Ceram Spinell offers glasslike light transmission by using the spinell cores instead of the alumina cores. And they have a high translucency like to natural tooth, an excellent margin integrity and a high strength(350MPa). The purposes of this study are 1) to know about the construction method of In-Ceram Spinell System, 2) to investigate the its clinical possibiliy through patients and literature reviews.