基于实测几何缺陷的圆柱壳外压承载能力分析

Analysis on external pressure bearing capacity of cylindrical shell based on measured geometric defects

[目的]为研究含真实几何缺陷的有限元模型建立途径,并基于不同类型缺陷对某缩比耐压圆柱壳结构的承载性能进行预测分析,[方法]提出基于二次型变换的几何缺陷提取方法,利用双重傅里叶级数表达实测初始几何缺陷,建立实测初始几何缺陷的引入方法。根据特征值模态型缺陷和实测缺陷,分别分析获得的缩比耐压圆柱壳的外压屈曲承载能力。[结果]结果显示,傅里叶级数法在不降低计算精度的前提下仅涉及网格节点的遍历和少量函数值的计算,使缺陷引入的计算效率得到显著提高。[结论]傅里叶级数法能够为圆柱壳结构极限承载能力的精确分析及结构优化设计提供指导。

[Objectives]The purpose of this paper is to study the way to establish finite element models with real geometric defects,and to predict and analyze the bearing capacity of a scale down pressureresisting cylindrical shell structure based on different types of defects.[Methods]Therefore,a geometric defect extraction method based on quadratic transformation is proposed,then the method of introducing the measured initial geometric defect,which is expressed by double Fourier series,is established. Finally, the buckling capacity of scale down pressure-resisting cylindrical shell under external pressure is analyzed and obtained based on eigenvalue modal defect and measured defect.[Results] The results indicate that Fourier series method only involves traversing of grid nodes and calculation of a few function values and can significantly improve the calculation efficiency of defect introduction without reducing the accuracy of calculation.[Conclusions]Fourier series method can provide guidance for accurate analysis of ultimate bearing capacity of cylindrical shell structure and structural optimization design.