TMD系统在单层球面网壳竖向减震中的应用

Application of a TMD system in reducing the vertical seismic responses of a single-layer reticulated shell

随着空间网格结构朝着大跨度、大空间的方向发展,结构在竖向地震作用下的响应不容忽视。为降低单层球面网壳在竖向地震作用下的结构响应,采用TMD系统对其进行竖向减震控制。以K8型单层球面网壳为研究对象,基于Kanai-Tajimi过滤白噪声模型合成了4条代表不同场地类别的激励波进行动力时程分析,以结构最大节点位移、最大Mises应力和最大加速度综合减震率为参考指标,探求了TMD质量比、调谐频率、阻尼比等参数对减震效果的影响规律,并优化分析了TMD系统在网壳上的布置位置。对网壳结构进行了矢跨比参数分析,比较发现:网壳矢跨比分别为1/7、1/5和1/3时,TMD系统减震效果呈随矢跨比增大而下降的趋势。建议TMD系统应用于单层球面网壳上时,其矢跨比不宜大于1/5。

With the development of space grid structure being larger in span and space,the structure responses caused by vertical seismic action cannot be ignored. In order to reduce the single-layer spherical reticulated shell＇s seismic responses under vertical seismic actions,the tuned mass damper（ TMD） system was adopted. Four stimulation waves composed from the Kanai-Tajimi model were chosen for dynamic time history analyses and the comprehensive reduction rates of the structure ＇s maximum node displacement,maximum Mises stress and maximum acceleration were acted as the reflection of the TMD performances. The influence curves of TMD ＇s mass ratio,tuning frequency and damper ratio were studied. Moreover,the location of the TMD system was optimized. The influences of the dome＇s rise span ratio were also analyzed.The numerical results show that as the rise span ratio changed from 1 /7 to 1 /3,the shock absorption effects went down. In order to ensure the controlling purpose,the dome＇s rise to span ratio was recommend not be more than 1 /5.