基于频率法的单索玻璃幕墙索力模拟分析

Analysis of cable force simulation for single cable glass curtain wall based on frequency method

为研究频率法在单索玻璃幕墙拉索索力监测中的准确性,基于某单索玻璃幕墙索力监测项目,采用有限元软件ANSYS建立幕墙拉索在不同边界条件下的振动模型,分析模拟频率与实测频率之间的关系,结果表明:幕墙拉索的边界条件更接近两端固支,并且短索更明显;高阶频率(n=3～6)较低阶频率(n=1～2)更稳定。将幕墙拉索的实测频率与边界条件为两端固支的模拟频率(n=3～6)进行比对,得到弦理论公式的频率修正系数为0.968,提出索力修正计算公式,其适用于长细比在270～340之间的单索玻璃幕墙拉索。采用弓式测力计法对修正公式进行验证,索力相对误差为-5.4%,表明该修正公式能有效提高索力计算精度。

In order to study the accuracy of frequency method applied to monitoring the cable force of single cable glass curtain wall,based on the cable force monitoring project of some single cable glass curtain wall, finite element software ANSYS was used to establish the vibration model of the single cable glass curtain wall under different boundary conditions,and the simulated frequencies were compared with the measured frequencies.The results showed that the boundary condition of the curtain wall cable is closer to the fixed ends,and the shorter cable is more obvious ;the higher order frequencies (n=3-6)are more stable than the lower order frequencies (n =1-2).The frequency correction coefficient was obtained by comparision of the measured frequency with the simulated frequency(n=3-6),and the number was 0.968calculated by string theory formula.A modifier formula was proposed,which was suitable for the cable of single cable glass curtain wall whose ratio of length to diameter was between 270-340.The modifier formula was verified by the bow type dynamometer method,and the relative error of the cable force was -5.4%,which showed that the calculation accuracy of the curtain wall cable force could be effectively improved by the modifier formula.