On the optimization of Tuned Mass Damper Inerter (TMDI) systems for buildings subjected to real ground motions using slime mould algorithm

This paper proposes a novel optimization framework for the optimal design of Tuned Mass Damper Inerter (TMDI) devices to mitigate the excess vibration of multi degree of freedom (MDOF) buildings under earthquake ground motions. Minimizing the H_∞- norm of the top floor displacement transfer functions is considered as the objective function for the optimization process. A Tuned Mass Damper Inerter (TMDI) is employed in which a TMD is placed at the top floor of a building connected via inerter. The top floor displacement of the building under eighteen (18) real earthquake ground motions classified in terms of low, intermediate and high frequency contents, is minimized using three optimization algorithms, particle swarm optimization (PSO), slime mould algorithm (SMA) and Harris Hawks optimization (HHO). The effectiveness of different algorithms is assessed using the RMS (root mean square) based values and the reduction ratio. The optimised parameters of the TMDI (mass ratio, frequency ratio, damping ratio and inertance ratio) obtained using the slime mould algorithm (SMA) are found to be better than the other optimization algorithms for the numerical example carried out in this paper. The results show that, the optimised TMDI has significant effect on the suppression of top floor displacement, acceleration with a lightweight TMD. The optimal parameters of TMDI shows a remarkable potential in suppressing maximum displacement reduction ratios of 0.83, 0.85 and 0.86 in response to low, intermediate and high frequency content earthquake ground motion, respectively. Based on the numerical results, the passive TMDI unveils a promising vibration calming system for damped elastic structure.