基于相关分析的对接接头缺口应力集中系数不确定性研究

Uncertainty study of stress concentration coefficient of butt joint notch based on correlation analysis

针对对接接头焊缝形状变化引起的缺口应力集中系数不确定性问题,基于参数化有限元分析和相关性分析进行研究。焊缝几何形状的不确定性由引入控制点的几何变化进行模拟,并基于仿真实验生成的大量测试数据样本计算控制点间的相关性,通过蒙特卡洛模拟获得大量随机焊缝数据。在缺口应力法基础上,使用ANSYS进行参数化建模,建立引入焊缝形状不确定性的对接接头有限元模型,对对接接头焊趾处的缺口应力集中系数进行研究,得到不同缺陷等级下的分布规律,总结了焊缝形状不确定性对缺口应力集中系数的影响。在此基础上,基于得到的大量实验数据建立焊缝几何参数的一阶响应面模型。结果表明:缺口应力集中系数与焊趾倾角及焊缝高度呈正相关,与焊缝宽度呈负相关,其中,焊趾倾角的影响最大,焊缝高度的影响最小。

Aiming at the uncertainty of notch stress concentration coefficient caused by the change of butt joint weld shape,the related study was carried out by using parametric finite element analysis and correlation analysis.The uncertainty of weld geometry was simulated by introducing geometric changes of control points,and the correlation between control points was calculated based on a large number of test data samples generated from simulation experiments.A large number of random weld data were obtained by Monte Carlo simulation.On the basis of the notch stress method,ANSYS was used for pa-rameterized modeling to establish a finite element model of the butt joint with introducing uncertainty in weld shape.The stress concentration coefficient of the notch at the weld toe of the butt joint was studied,and the distribution patterns under different defect levels were obtained.The influence of weld shape uncertainty on the stress concentration coefficient of the notch was summarized.On this basis,a first-order response surface model of weld geometry parameters was established based on the large amount of experimental data.The results show that the stress concentration coefficient of the notch is positively correlated with the inclination angle of the weld toe and the height of the weld seam,while negatively correlated with the width of the weld seam.Among them,the inclination angle of the weld toe has the greatest impact,while the height of the weld seam has the smallest impact.