“…Two dimensional mass, μ r , and frequency, f r , ratio are introduced to standardise the structure-damper system (Elias and Matsagar 2018;Salvi et al 2018): where f d is the mass damper frequency (= 1/T d ) and Ω s,j = Ω s,1 ,…,Ω s,n (= 1/T s,1 , …, 1/T s,n ) is the selected modal frequency of the structure corresponding to the mode j. A possible criterium to distribute the damper masses on the structure is carrying out the modal analysis (Elias and Matsagar 2018;Wu et al 2011).…”