EVOLUTIONARY MODEL OF VISCOELASTIC DAMPERS FOR STRUCTURAL ApPLICATIONS

Th 7 effe~ts oftempe~atureon the energy dissipation of viscoelastic dampers for seismic mitigation of structures are mvestigated. To Simulate the damper behavior, an evolutionary model is proposed to describe ~e dependence o~ ~e ~echanical propertie~ of th~ damper on the deformation frequency and the temperature mcre~e due to diSSipation. Thermorheologlcally Simple materials are considered and the influence of the de­ formatio~ frequency on the storage and loss moduli is modeled using fractional derivative operators. The effect of m~tenal temperature on the for~e-~eformation relation is modeled using the concept of evolutionary transfer func~0!1' and the proposed model IS Implemented using a step-by-step technique in the frequency domain. The p~edictions. of the proposed. model in the case of sinusoidal and seismic deformations show good agreement with e~penmental results. Fmally, the response spectra of single-degree-of-freedom structures with added vis­ coelastic ~pers and subjected to seismic excitation are computed using the proposed evolutionary model; the results obtained show that the thermal effect due to energy dissipation is not always negligible.

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