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Design of Optimal Slit Steel Damper Under Cyclic Loading for Special Moment Frame by Cuckoo Search
Masoud Zabihi-Samani 한국강구조학회 2019 International Journal of Steel Structures Vol.19 No.4
After the Northridge and Kobe earthquakes, several destruction of the structural beams were occurred. The diffi culty and cost-eff ectiveness of beam replacement after earthquakes is a major problem on steel structures. For this purpose, the idea of using replaceable connection is suggested. A slit steel damper (SSD) is introduced that leads to the further energy damping and the ability to move the plastic joint outside of structural elements. The stiff ness and damping characteristics of SSD is related to the thickness, height and number of sheets of the damper. The usage of SSD is more progressive and at the same time, the optimal design of SSDs should be proposed to meet the economical criterion and the reduction of the stress and defl ection. In this study, an optimal SSD connection is proposed to enhance the performance of the classical SSD connection to meet the criterion of AISC to utilize in special moment frames. The results demonstrated that increasing the thickness and reduction of the steel sheets in the damper had a greater eff ect on the performance of the SSD connection, in comparison with the increase in the number of sheets. Therefore, the Cuckoo Search (CS) was utilized to optimize the several SSD parameters. Furthermore, a comparison between the CS-SSD and Reduced Beam Section (RBS) which is known as a common moment steel fi xed-connection was accomplished. Results indicate that CS-SSD connection can reach the same function as the RBS connections under cycling loadings, in addition to the easy replacement capability after seismic excitations. The performance of the proposed CS optimization algorithm in designing of the optimal SSD was compared with the traditional Genetic Algorithm and the particle swarm optimization (PSO) with considering several designing constraints. High capabilities of the proposed CS optimization algorithm in terms of weight, energy absorption, stiff ness and bearing capacity of SSD connections are simultaneously clarifi ed by the results.
Optimal Control of Steel Structures by Improved Particle Swarm
Saeid Aghajanian,Hadi Baghi,Fereidoun Amini,Masoud Zabihi Samani 한국강구조학회 2014 International Journal of Steel Structures Vol.14 No.2
Active control is one of the modern approaches in seismic design of steel structures. Recently, induced by economicconsiderations, especially high expenses of control systems, optimality has become an important issue. In this paper an activesystem is used to control a steel structure’s displacements by a simplified pole assignment method. To optimize the number,the locations, and the total driving force of the required actuators, an improved particle swarm algorithm is presented focusingon the parameters of the velocity equation. A Geographical neighborhood topology and an adaptive inertia weight are used toimprove the standard PSO algorithm. In addition to the local and global best solutions, the positions of the best particles inthe geographical neighborhood are mathematically represented in an additional term. The performance of the proposedalgorithm is compared with the traditional Genetic Algorithm (GA) and the standard particle swarm considering the optimalcontrol of a 12-story steel structure as a numerical example. High capabilities of the proposed method in terms of the controltarget, convergence rate, and accuracy are simultaneously clarified by the results.