The study presented herein refers to investigation of ways to reduce investments necessary for performing progressive collapse analyses in terms of computational costs and time. The first part of this study is focused on implementation of reduced finite element (FE) modeling approach to simulate complex models featuring low computational power requirements. Good agreement with experimental results is obtained by reducing mesh sensitivity of FE model using the constant fracture energy approach. Mesh regularization on steel material is performed in analogous way by conserving total rupture energy. The use of single FE material model for both concrete and steel material applied to the whole structural frame produces good convergence with experimental results, while reducing modeling complexity and maintaining computational efficiency of the proposed approach. A parametric FE modeling program is proposed to reduce time and complexity of pre-processing stage of FE progressive collapse analysis. Object-oriented parametric modeling approach using Python programming language is demonstrated to be time-efficient in generating complex FE models with ease and flexibility. The parametric modeling software is then utilized to produce automated parametric optimization tool based on Covariance-Matrix-Adaptation Evolution Strategy (CMA-ES). The implemented algorithm is demonstrated to be applicable to objective functions defined through input-output relations involving the use of results of FE simulations. The applicability of the proposed automated parametric optimization approach is demonstrated through investigating case studies that involve large number of search space dimensions and computationally intensive evaluations of functions. Overall, good performance of automated conduction of parametric studies is observed.
본 연구에서는 연쇄 붕괴 해석에 소요되는 계산시간을 단축하고 결과의 정확도를 높이기 위한 해석법을 제안했다. 보 요소를 활용하여 3차원의 해석 모델을 2차원으로 단순화하여 계산 효율성을 높였으며, 모델을 구성하는 콘크리트 및 강재를 단일 재료로 구성함으로써 계산의 복잡성을 줄이고 실험과 유사하게 해석 조건을 구성하였다. 콘크리트와 강재 모델의 적절한 메쉬 크기를 산정하기 위해서 파괴 에너지 접근법을 이용하여 파라미터 연구를 수행하였으며, 실험결과와 좋은 일치도를 보였다. 메쉬 크기를 변경 할 때마다 모델링에 소요되는 시간을 줄이기 위해 객체지향 설계법 기반의 코드를 이용하여 쉽게 모델을 구현하였으며, CMA-ES (Covariance-Matrix-Adaptation Evolution Strategy)를 이용하여 자동화된 파라미터 연구를 수행했다. 많은 파라미터를 갖는 유한요소 모델에 제안된 CMA-ES 기반의 코드가 적용가능함을 보였다.
