سيد ميلاد حسيني

Optimization is a process in which the optimizer is attempt to find the best-optimized solution that fulfills all design requirements. In past decades, researchers attempt to solve optimization problems using a mathematical-based optimization technique, such as a gradient-based algorithm. However, in recent years, with increasing the complexity of the optimization problems and inefficiency of gradient-based methods, metaheuristic optimizers as probabilistic solvers have become popular among researchers and scientists due to their capability of exploring and finding promising regions in the search space at an affordable computational time. Thus, the successful growth of these types of optimization methods has been impressive. According to the NFL theorem, there is no metaheuristic algorithm well suited for all types of problems. In this regard, the NFL theorem encourages many researchers to develop effective and efficient metaheuristics for each field of engineering, such as structural engineering. In this thesis, to achieve optimal design of different types of steel structures, two research phases are considered. In the first phase, new metaheuristic algorithms and improved variants of existing metaheuristics are proposed. To develop new metaheuristics, physics rules are selected as the source of inspiration and two novel metaheuristics named PGO and DE-MEDT are proposed. PGO and DE-MEDT algorithms are respectively inspired by plasma generation in quantum physics and Doppler Effect combined with the mean Euclidian distance threshold. In association with the improved version of existing algorithms, by examining the strengths and weaknesses of BA and Jaya algorithms, two improved variants of these algorithms namely IBA-DE based on the Doppler Effect phenomenon and IS-Jaya based on the shuffling process are presented. In the second phase of the current thesis, different types of steel structures are modeled to eva‎luate the performance of the proposed algorithms in terms of robustness and convergence rate. Benchmark trusses and frames, grids, domes, barrel vaults, and cable-equipped barrel vaults are the structures that are optimized using the proposed methods. Comparing the optimization results obtained by the proposed methods with those of other methods found in the literature indicate the suitable performance of the proposed optimizers for the optimal design of the considered steel structures.

طراحي بهينه سازه ها , الگوريتم هاي فراكاوشي , سازه هاي اسكلتي و كابلي , الگوريتم تشكيل پلاسما , الگوريتم اثر دوپلر

Optimal design of structures , Metaheuristic algorithms , Skeletal and cable structures , Plasma Generation Optimization , Doppler Effect

Seyed Milad Hosseini

Prof. Ali Kaveh