国家网球馆开合屋盖结构阻尼比研究

Study on damping ratio of retractable roof structure of National Tennis Hall

对于大跨空间结构(混合结构)的等效阻尼比目前还没有统一的取值方法,一方面是因为混合结构由不同材料组成,其各部分的阻尼机理和振动特性不同,导致混合结构阻尼机理更为复杂;另一方面目前常用的复阻尼理论中,由于复刚度矩阵的存在最后往往得出复数,计算复杂。因此,文中从阻尼比的本质出发,以能量的角度计算开合屋盖混合结构的阻尼比,并以国家网球馆——钻石球场为工程背景,对其开合屋盖结构在地震作用下的结构特性进行分析,研究开合屋盖结构处于不同开合状态下的阻尼比发现,一致阻尼比的均值都小于模态阻尼比的均值。其中开合屋盖全闭状态时两者的差值最小,在其他几种开合状态下,两者相差在2%~7%范围内,说明一致阻尼比的方法更能反映结构的耗能特性,同时可以考虑结构的质量和刚度等参数,从而能够得到更加合理的结构阻尼比。研究结果可为精确计算开合屋盖结构的阻尼比以及同类开合屋盖结构在地震作用下地震响应分析提供参考。

For long-span spatial structures,there is no unified calculation method for the equivalent damping ratio of this kind of composite structures( on the one hand composite structures include different materials with different damping mechanisms and vibration characteristics,so damping mechanism of composite structures is more complex.On the other hand complex stiffness matrix often obtains complex number in commonly-used complex damping theory which causes inconvenience to engineering application). Based on the essence of damping ratio the damping ratio of retractable roof structure is calculated in terms of energy. Taking National Tennis Hall-Diamond Court as the project background,the characteristic of retractable roof structures under seismic action was analyzed to study the damping ratio characteristic of the retractable roof structure with different opening statuses. It is found that the average consistent damping ratio is less than the average modal damping ratio. There is a minimum difference between the two damping ratios in fully closed retractable roof,and in other states the difference ranges from 2% to 7%,which means the consistent damping ratio can reflect the structural energy dissipation better. Meanwhile,it can consider parameters like structural quality and stiffness to get more reasonable structural damping ratio. The research results can provide reference for precise calculation of the damping ratio of retractable roof structure and seismic response analysis of similar retractable roof structure.