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김영민,김치경,김태진,Kim, Yeong-Min,Kim, Chee-Kyeong,Kim, Tae-Jin 한국전산구조공학회 2007 한국전산구조공학회논문집 Vol.20 No.6
본 연구에서는 새로운 비선형해석 알고리즘인 적응형 Newton-Raphson 반복기법을 제안한다. 제안된 기법은 기존 Newton-Raphson 기법을 근간으로 적응형 부구조물화 기법을 이용하여 강성등가하중을 구하고, 이미 역행렬이 계산되어 있는 초기강성행렬에 강성등가하중을 적용하여 보정변위를 구하는 것으로 요약된다. 제안된 알고리즘의 가장 큰 특징은 하중 구간의 수에 관계없이 구조물 강성행렬에 대한 역행렬 계산을 단 한번만 수행한다는 것이다. 제안된 기법의 효율성은 강성행렬 및 역행렬 계산 후 부재강성행렬이 변경된 부재들이 연결된 자유도 수와 전체 자유도 수의 비율에 직접 관계된다. 이 비율에 따라 제안된 기법을 기존 비선형해석 기법과 보완적으로 사용함으로써 전체 비선형해석 효율을 향상시킬 수 있다. This paper presents a new nonlinear analysis algorithm, that is, adaptive Newton-Raphson iteration method, The presented algorithm is based on the existing Newton-Raphson method, and the concept of it can be summarized as calculating the equivalent load for stiffness(ELS) and adapting this to the initial global stiffness matrix which has already been calculated and saved in initial analysis and finally calculating the correction displacements for the nonlinear analysis, The key characteristics of the proposed algorithm is that it calculates the inverse matrix of the global stiffness matrix only once irresponsive of the number of load steps. The efficiency of the proposed algorithm depends on the ratio of the active Dofs - the Dofs which are directly connected to the members of which the element stiffness are changed - to the total Dofs, and based on this ratio by using the proposed algorithm as a complementary method to the existing algorithm the efficiency of the nonlinear analysis can be improved dramatically.
김영민,김장희,이슬기,Kim, Yeong-Min,Kim, Jang-Hee,Lee, Seul-Gi 대한건축학회 2012 대한건축학회논문집 Vol.28 No.5
In this paper, we reviewed structural safety of the real-built new traditional Korean-style house and proposed appropriate section for the main structural members. The mechanical properties of wood depends on the terms and conditions of the environment, so we applied correction factors in obtaining design allowable stress. The structural safety was checked by investigating allowable stress ratio, that is, the ratio of actual stress to the design allowable stress. As the results of the strength check, the stress ratio for the columns are about 48~50%, and for flexural members such as purlin and beam are about 49~66% level. For the serviceability review, the defection of the main flexural members were about 25~64% level compared to the allowable deflection. We proposed appropriate sectional size for the main structural members still satisfying safety and serviceability criteria reflecting structural characteristics such as steel connection and needs to expanding supply. Here, the referenced stress ratio for the strength check was set to 80% level considering possible error and imperfection. As a results, the cross-sectional size can be reduced up to about 20~30% for columns and 20~50% for flexural members.