本帖最后由 sunnygu 于 2014-10-30 03:52 编辑
我的结论是,你的分析可以得出,ovality对第几阶模态贡献最大(在一定载荷下,比如是外压还是轴向压力,下一步可以考虑bending moment),以及为Imperfectiion分析所取得因子。如你说的,吻合很好。
所有code都是规定最大的厚度tol和ovality. 这样就可以引入imperfection值,求得critical loading。你做的ovality分析support 前几阶modes考虑进去以及具体数值。工程上分析不可能几千米的管子建立不同的截面。所以包络线都是对的在code里。
Stochastic FEM Based Stability Analysis of I-Sections With Random Imperfections. (thesis)
EU-3 BUCKLING说明等都可以作为参考。直接取了一个系数
The imperfections remove the sharp discontinuity in the load-deflection response. It is customary to use one to ten percent of the beam/shell thickness as the maximum imperfection introduced--ANSYS
Geometric imperfections or perturbation loads should be introduced. Geometric imperfections introduced with modes from the linear buckling analysis are recommended. The magnitude of imperfection should be within the range of manufacturing tolerances
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