Metaheuristic based optimization of tuned mass dampers on single degree of freedom structures subjected to near fault vibrations

Yıl 2019, Cilt: 3 Sayı: 2, 86 - 92, 10.10.2019

Sinan Melih Nigdeli Gebrail Bekdaş Aikerim Aydın

Öz

Near fault ground motions excitations have specific
characteristics comparing to regular earthquake excitations. Near fault ground
motions contain directivity pulses and flint steps in different directions and
these excitations are the reason of more damages than regular excitations for
structures. A successful method to reduce structural vibrations is the usage of
tuned mass dampers. By using optimally tuned mass dampers, it will be possible
to reduce vibrations resulting from earthquake excitations. In the present
study, the optimization of tuned mass dampers are done for near fault
excitations. During optimization, 6 different pulse like excitations are used.
Three of these excitations are directivity pulses while the other ones are
flint steps. The periods of excitations are 1.5s, 2.0s and 2.5s since near
fault pulses have long period and big peak ground velocity around 200 m/s. The
optimization objectives are related to maximum displacement of structure in
time domain, the maximum stroke limitation of tuned mass damper and transfer
function of the structure in frequency domain analyses. The iterative
optimization process uses both time and frequency domain analyses of the
structure. Three different metaheuristic algorithms are used in the
methodology. These methods are harmony search algorithm, teaching learning
based optimization and flower pollination algorithm which are inspired from
musical performances, education process and reproduction of flowering plants,
respectively. As the numerical investigation, three different single degree of
freedom structures with periods 1.5s, 2.0s and 2.5s are investigated for
optimum mass, period and damping ratio of a tuned mass damper positioned on the
structure.

Anahtar Kelimeler

Metaheuristic algorithm, Near fault vibrations, Optimization, Tuned mass dampers

Kaynakça

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