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初始几何缺陷对弦支穹顶的稳定性能有较大的影响。在结构整体稳定性计算中,利用随机缺陷模态法为结构施加合理的初始几何缺陷是该文的主要研究目的。首先采用一致缺陷模态法,在不同初始几何缺陷下,对肋环2型弦支穹顶结构进行稳定性能分析,然后讨论随机缺陷模态中方差的取值方法,并利用该方法对肋环2型弦支穹顶结构进行了210种不同初始几何缺陷下的稳定性能分析,两种分析方法所施加缺陷的最大值均为结构跨度的1/300。分析结果表明:结构的初始几何缺陷对结构的稳定性能影响较大,考虑初始几何缺陷后结构稳定性能为完善结构的50%左右,且采用一致缺陷模态法时也需通过考虑不同缺陷分布形式的多次计算才能合理评估结构的稳定性能,建议在跨度较大、较为复杂的结构中采用随机模态法来考虑初始几何缺陷对结构稳定性能的影响。
The initial geometric defects have a greater impact on the stability of the chord dome. In the calculation of overall structural stability, it is the main research purpose of this paper to apply reasonable initial geometric defects to the structure by stochastic defect mode method. Firstly, the uniaxial defect mode method is used to analyze the stability of ribbed 2-type suspen-dome under different initial geometric imperfections. Then, the method for determining the variance of stochastic defect modes is discussed. The analysis results show that the maximum of the defects imposed by the two methods are all about 1/300 of the span of the structure. The results show that the initial geometric imperfection of the structure has a great influence on the stability of the structure. The structural stability of the initial geometric imperfection is about 50% of that of the perfect structure. When the uniform defect mode is adopted, It is suggested to adopt the stochastic modal method to consider the influence of the initial geometric imperfection on the structural stability in the structure with large span and complex structure.