Effects of manufacturing type on control performance of multiple tunedmass dampers under harmonic excitation

Using different optimization techniques, the optimum characteristics of multiple tuned mass dampers (MTMD) for reducing the dynamic response of primary structure due to various excitations are studied by many researchers. In this paper, the five practical MTMD models are considered which consist of different combinations of the mass, damping, stiffness coefficient and damping ratio in the MTMD. The criteria selected for the optimality is the minimization of the maximum value of the displacement dynamic magnification factor (DMF) of the primary structure with the MTMD system under external harmonic excitation. The optimum parameters of the MTMD systems are investigated using Sequential Quadratic Programming (SQP). Results obtained illustrate that the optimum MTMD-1 and MTMD-4 have nearly the same control performance and provide higher effectiveness than all the other types of MTMDs of the same mass ratio in reducing the displacement response of primary structure. Finally, a robustness analysis of optimally designed MTMD systems to investigate their performance under errors in the tuned frequencies is also performed in detail.