Controle passivo de vibrações em sistema estrutural utilizando molas superelásticas: comparação entre técnicas e análise da influência de variáveis

Abstract

The growing concern with the efficiency and reliability of the application and use of structural systems has led researchers around the world to seek techniques to control vibrational effects in civil structures. This is the case for narrow, flexible buildings that are highly vulnerable to earthquakes, crosswinds, and impacts. Among the available methods, passive control stands out for its low cost, low maintenance and does not require an external source of energy. Thus, this work aims to design and test attenuators of coil springs manufactured with Shape Memory Alloy (SMA), Superelastic (SE) of NiTiNOL. These devices will be applied in a 3DOF building simulator prototype for vibration control. The system functions as a Vibration Isolation Recentering Device (VIRD). The objective is to evaluate the influence of variables such as displacement (zero points of displacement) and strain amplitudes of the elements associated with excitations. Also, compare them to other techniques such as side bracing and Tuned Mass Dampers (TMD). It was concluded that the length of the attenuator directly influences the control, with smaller ones showing greater efficiency. This generates more hysteresis and dissipates up to 29 times more mechanical energy. In addition to reducing the amount of material used. The effect of self-heating was negligible in this study, as the temperature gradient was less than 10ºC, as well as the offset, which had no significant influence on the control process. In terms of amplitudes observed in the experimental modal analysis, TMD was the most efficient technique allowing reductions of up to 74% in free vibration. In seismic and forced vibration, VIRD proved to be the most effective among the techniques, reducing the response by about 80% in the analysis of two seismic signals. Thus, the originality of this research lies in the proposal to compare passive control techniques. In addition to the optimization of SMA attenuators by calibrating systems from an algorithm developed in a computational environment.