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针对双曲壳体冷却塔的静风整体稳定进行研究,介绍了现行规范条款的试验背景,探讨了其试验方法和结果,并对试验结果和计算结果进行比较分析。以现阶段代表性大型双曲壳体冷却塔为例,在动力特性分析的基础上,研究了其分支点和极值点整体失稳特征和内压取值及加劲环设置对整体稳定性的影响。研究发现:冷却塔塔筒的振型可以看作是上下弹性支撑水平圆环结构和左右弹性支撑子午向悬臂结构振型的耦合;其风压作用下的几何非线性特征并不明显,结构的失稳是突然发生的,极值点失稳形态既表现出静力计算的变形特征,又带有分支点屈曲模态的倾斜谐波;冷却塔整体稳定性随内压取值的增加而显著下降,而增设加劲环能够增加和协调塔筒刚度分布从而提高结构的稳定性,并且加劲环设置在失稳形态变形最大的位置效果最为显著。
In view of the overall stability of the static wind in the hyperbolic shell cooling tower, the experimental background of the current regulation is introduced, the test methods and results are discussed, and the test results and the calculation results are compared and analyzed. Taking the representative large hyperbolic shell cooling tower as an example, on the basis of dynamic characteristics analysis, the overall instability characteristics and internal pressure values of the branch points and extreme points and the setting of stiffener ring on the overall stability influences. It is found that the mode shapes of cooling towers can be regarded as the coupling of the upper and lower elastic support horizontal ring structures and the vibration modes of the left and right radial support cantilever structures. The geometrical nonlinear characteristics under wind pressure are not obvious, Instability is abrupt, and the instability of the extreme point shows both the deformation characteristics of the static calculation and the oblique harmonic of the buckling mode of the branch point. The overall stability of the cooling tower increases significantly with the increase of the internal pressure While the addition of stiffening ring can increase and coordinate the stiffness distribution of the tower to improve the stability of the structure. Moreover, the setting of the stiffener ring is the most obvious at the position where the deformation of unsteady shape is the largest.