Plastic Analysis of Braced Frames by Application of Metaheuristic Optimization Algorithms

The plastic analysis of moment frames by the combination of elementary mechanisms is one of the classic problems in the field of nonlinear analysis of structures. This method, based on the principles of the upper-bound theorem, has so far been used in much research. The application of optimization algorithms in structural engineering resulted in the use of this method for high-rise structures and determination of the collapse load factor along with the critical failure mode. The most important feature of this method is the simplicity of application without the need for complex analysis or software. Nevertheless, the only disadvantage is its exclusivity for moment frames. In this study, with the help of the existing principles for moment frames, the method is developed for braced frames. To this end, various optimization algorithms have been used to examine the convergence rate and compare them with each other. In this research, the genetic, modified dolphin echolocation, grey wolf, and whale algorithms are used to optimize the proposed method. By comparing the results for three samples, the genetic and modified dolphin echolocation optimization algorithms provided far more accurate results. Although, there is a little error in the grey wolf algorithm and much more in the whale algorithm.