Multi-objective optimisation of steel moment frames subjected to blast

In recent decades, terrorist attacks have been increased all over the world. For this reason, the design of blast resistant structures is very crucial. On the other hand, for decades the optimum design of structures has been an interesting subject for structural engineers and researchers as it can provide cost and behavioural efficiencies. In the current research, the optimum design of steel moment frames under blast loading has been studied. Towards that end, first, a damage index is developed based on the maximum plastic strain in the members. Then, according to the damage index, a multi-objective optimisation methodology is proposed to minimise the structural weight and the damage index. The method utilises explicit nonlinear dynamic finite element analysis as the structural analysis method and NSGA-II optimisation algorithm as the optimisation technique. At the final point, based on the proposed method a framework is developed, and two numerical examples are studied. Results of this research show that the developed method is effective in achieving optimal designs with desired cost and damage.