改进型减震自复位负刚度机构抗震机理数值模拟

Numerical simulation on seismic mechanism of modified negative stiffness device with seismic reduction and self-centering

为了进一步改善既有负刚度机构的抗震性能,开发了增设与预压弹簧并行的辅助耗能元件的改进型减震自复位负刚度机构。以负刚度机构中预压弹簧刚度和预压位移作为设计参数设计了5个足尺试件,并采用商业有限元软件ABAQUS对其在水平低周往复荷载下的抗震机理进行了数值模拟。基于模拟数据处理,对其滞回特征、水平抗侧刚度和耗能能力等性能进行了对比分析。结果显示,预压弹簧刚度不仅影响负刚度对结构弱化减震的发展进程,且影响消压后对结构强化自复位的功效,而预压弹簧预压位移设计值仅影响负刚度对结构弱化减震的发展进程;设置与预压弹簧并行的辅助耗能元件可提供耗散地震能的能力,从而进一步增强结构的减震效果。因此,新型减震自复位负刚度机构实现了减震、耗能能力与自复位功效有机统一的性能设计目标。

To further improve seismic performance of the negative stiffness Device（ NSD）,a modified negative stiffness device（ MNSD） was developed with supplemental energy-dissipation component installed in parallel to pre-compressed spring to enhance its energy-dissipation capacity.Design parameters as stiffness and prescribed displacement of pre-compressed spring were taken into account to design 5 full-scale specimens,and the commercial FE software ABAQUS was adopted to simulate their seismic behavior under lateral low-cycle reversed loading. Based on the analysis data,the specimen＇s performance were analyzed,including hysteretic characteristics,horizontal lateral stiffness and energy-dissipation. The results indicate that the stiffness and prescribed displacement of pre-compressed spring both affect the process of weakening the structure to reduce the seismic response,while the stiffness of pre-compressed spring also affects the strengthening and selfcentering of structure after the decompression of pre-compressed spring; that the supplementalenergy-dissipation component can provide energy-dissipation capacity for the structure to further reduce the seismic response. Therefore,MNSD meets the performance design target of seismic reduction,energy dissipation capacity and self-centering.