Estudo de um amortecedor de massa auxiliar sintonizável utilizando amortecedor por atrito semiativo

Abstract

The auxiliary mass damper is often used to reduce excessive vibration amplitudes in mechanical systems. However, their performance is susceptible to changes in the frequency or form of the excitation force. Therefore, to improve their robustness, it is necessary to design adaptive systems that can be used efficiently over a large frequency range. This work presents the study of a tunable auxiliary mass damper that has a semi-active friction damper in its suspension applied to reduce vibration amplitudes in mechanical systems. The dynamic behavior of the device is analyzed considering the influence of the tangential stiffness’ magnitude, the friction force at the contact, and the direction of the friction force in relation to the movement of the primary system. From these analyzes, control logics are proposed to benefit from the high capacity of the semi-active friction damper to dissipate mechanical energy. Numerical simulations evaluating the efficiency and robustness of the device in vibratory systems with single and with three-degree-of-freedom were performed. Different assemblies using semi-active friction dampers and tunable auxiliary mass dampers were numerically simulated in a three-story steel structure. The efficiency of the best assemblies was evaluated by means of numerical responses that use seismic records as base excitations. The results show that the tunable auxiliary mass damper is an excellent energy sink, able to increase the structure’s robustness and attenuates the vibration in a wide frequency range. Their combined usage with the semi-active friction damper has presented a great performance in the seismic protection of structures.