大跨网架结构风振响应及阻尼减振分析

ANALYSIS ON WIND VIBRATION RESPONSE AND DAMPING VIBRATION REDUCTION OF LONG-SPAN GRID STRUCTURES

设计制作了带挑檐大跨度平屋盖刚性结构模型,对其进行风洞试验,得到不同模型屋盖表面测点的平均风压与脉动风压系数,利用本征正交分解(POD)法计算节点处的风压系数,采用有限元分析软件ANSYS对原型屋盖网架结构进行风振响应以及减振分析。结果表明:挑檐部分由于上下表面风压叠加作用,负风压较大;在挑檐角部设置黏弹性阻尼器,对挑檐风振响应控制效果显著;存在一定程度既有锈蚀的网架结构,设置黏弹性阻尼器对风致响应减振效果明显,风致响应随锈蚀深度增加而增大,锈蚀深度小于1 mm时,位移响应均方根值减振系数达到10.3%~21.0%,加速度响应峰值减振系数达到26.3%~39.6%。

A rigid structure model of long-span flat roof with overhanging eaves was designed and tested in wind tunnel.The average wind pressure and fluctuating wind pressure coefficients of the measured points on the surface of the model roof were obtained.Then the wind pressure coefficients at the joints were calculated by proper orthogonal decomposition(POD)method.The finite element analysis software ANSYS was used to analyze the wind-induced vibration response and the performance of vibration reduction.The results showed that negative wind pressure of overhanging eaves was large due to the superposition of upper and lower surface wind pressure.The effect of adding viscoelastic dampers on the corners of the eaves was remarkable for controlling the wind-induced vibration response of overhanging eaves.For the existing grid structures with certain degree of corrosion,the wind-induced response increased with the increase of corrosion depth,and the viscoelastic damper had an obvious effect on wind-induced vibration reduction.When the corrosion depth was less than 1 mm,the damping coefficient of root mean square of displacement response reached 10.3%~21.0%,and the damping coefficient of peak acceleration response reached 26.3%~39.6%.