负刚度非线性能量阱减震控制性能研究

提出设置含负刚度特性的非线性能量阱（NES）来实现结构地震响应控制，针对典型的单层和双层层模型，在附加质量占主质量5%的限定条件下，对采用负刚度NES、立方NES和经典质量调谐阻尼器（TMD）控制方式的装置参数进行数值寻优，对优化的减震控制性能进行对比分析。结果表明，负刚度NES减震控制性能全面优于已有的立方NES，对主结构动力特性变化的鲁棒性优于TMD，对地震动峰值变化的鲁棒性与TMD相当。应用数值小波变换对体系的地震响应时程进行功率谱分析，揭示了在地震作用过程中，负刚度NES总体上对主结构产生更为显著、更为持续的瞬时内共振俘获行为，因而其减震效率较高，且由于这种瞬时内共振俘获是在多频域上同时展开的，使其减震控制性能具有强鲁棒性。

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.