含模态缺陷的环向加肋圆柱壳极限强度分析

Ultimate strength analysis of circumferential ribbed cylindrical shells with modal defects

为了研究初始缺陷对环向加肋圆柱壳极限强度的影响,引入模态缺陷作为圆柱壳的初始几何缺陷。首先,建立与实物模型一致的有限元模型,依据模态形状特点将前30阶模态归为4类,发现类别一的第23阶模态得到最低的极限强度,并对含有模态缺陷的圆柱壳进行半径厚度比、缺陷幅值、不同材料的敏感度分析。结果表明:极限强度与不同厚度半径比、缺陷幅值均呈近似线性关系;不同材料加肋圆柱壳的最低极限强度对应的模态阶数不同,但其模态形状均为同一类。

In order to study the effect of initial defect on the ultimate strength of circumferential ribbed cylindrical shell modal defect is introduced as the initial geometric defect of cylindrical shell.Firstly,a finite element model consistent with the physical model was established,and the first 30 modes were classified into four categories according to the shape characteristics of the modes.It was found that the 23rd mode in the first category obtained the lowest ultimate strength,and the radius-thickness ratio,defect amplitude and sensitivity of different materials were analyzed for cylindrical shells with modal defects.The results show that the ultimate strength is approximately linear with different thickness radius ratio and defect amplitude.The modal order corresponding to the minimum ultimate strength of different materials is different,but the modal shape is the same.