老龄飞机多部位损伤结构的剩余强度研究

Residual Strength of Multiple-site Damage Structure Using Interactions of Dugdale-type Cracks and Stable Tearing

对老龄飞机的多部位损伤壁板进行剩余强度估算时,应同时考虑裂纹间的相互影响和裂纹的扩展问题。基于Dugdale型裂纹的Swift连通准则,结合扯裂断裂准则,论文提出了应用应力函数交互迭代方法来研究MSD壁板的剩余强度问题,并做了算例阐明。本文所提方法的分析结果与试验值相比平均相对误差和标准差分别为-1.46%和0.069,符合得较好。

We present an investigation method of residual strength of Multiple Site Damage （MSD） panel. Both interaction between cracks and the effect of stable tearing are considered together. Dugdale model of collinear cracks is employed in the MSD panel model. Swift strip-yield criterion is used to judge whether the cracks link up. Compared with the test results, the average relative error μ and root-mean-square error σ of the numerical results are - 1.46 % and 0. 069 respectively. It shows that the proposed method can provide a reasonable prediction for the residual strength of MSD panel on an aging aircraft. We draw the following conclusions for residual strength investigation of MSD panel： 1） the length of strip （space between cracks） strongly affects the residual strength of MSD panel; 2） the plastic zone sizes of crack tips under interaction between cracks should be calculated correctly; 3） the effect of stable tearing which is the R-curve of the MSD panel should be considered in crack propagation, otherwise, the residual strength of MSD panel cannot be estimated correctly.