A STUDY ON STRUCTURAL SEISMIC CONTROL PERFORMANCE BY NONLINEAR ENERGY SINKS WITH NEGATIVE STIFFNESS

A nonlinear energy sink (NES) with negative stiffness is presented for structural seismic response control. Typical analysis model is studied by attaching a NES with negative stiffness, a NES with cubic nonlinear stiffness, or a classical tuned mass damper (TMD). The parameters of different devices are optimized numerically, and their control performaces are compared under the condition that the attaching mass is less than 5% of the parimary structure. The anlysis results shows that the seismic control performance of the present NES with negative stiffness is thoroughly superior to that with cubic stiffness. As the dynamic characteristics vary, its control performance shows stronger robustness than that of the TMD. As the peak ground accceration varies, it shows similar robustness performance as the TMD. The numerical wavelet transformation is applied to analyze the structural seismic response histories by power spectra. The results indicate that more intense and durable transient internal resonance captures can be obtained by the NES with negative stiffness, and thus it shows higher control efficiency. Furthermore, as such transient internal resonance captures can be derived in a wide frequency domain, particularly as those transient subharmonic resonance captures are insensitive to variation of foundamental frequency of the primary structure, its control performance possesses strong robustness.