缺口部件极端不规则裂纹前沿生长规律研究  

RESEARCH ON THE GROWTH LAW OF EXTREME IRREGULAR CRACK FRONT IN NOTCHED COMPONENTS

作　　者：李冲[1] 高鹏[1] 谢里阳 LI Chong;GAO Peng;XIE LiYang(Department of Mechanical Engineering,Liaoning Petrochemical University,Fushun 113001,China)

机构地区：[1]辽宁石油化工大学机械工程学院,抚顺113001

出　　处：《机械强度》2024年第5期1236-1242,共7页Journal of Mechanical Strength

基　　金：辽宁省教育厅高校基本科研项目(51019170),辽宁省教育厅科学研究经费项目(L2019019);抚顺市“抚顺英才计划”资助项目(FSYC202107014);辽宁石油化工大学引进人才科研启动基金项目(1100011689)资助。

摘　　要：真实的、极端不规则裂纹前沿生长路径预测直接影响结构剩余疲劳寿命评估的准确度。以与工程结构在几何上局部最为相似的缺口部件为裂纹受体,构建了一种不规则裂纹前沿应力强度因子(Stress Intensity Factor,SIF)分布规律研究方法。首先,利用高分辨率样条曲线表征不规则裂纹前沿上由于凸区、凹区以及小曲率半径引起的局部曲率变化;然后,基于自适应网格划分技术结合子模型法迭代模拟不规则裂纹前沿生长迹线,得到不规则裂纹扩展规律;最后,通过算例验证Franc3D计算裂纹扩展驱动力的可靠性,将预测得到的裂纹几何与试验测得的裂纹位置、尺寸等信息进行比较。结果表明,预测得到的裂纹前沿迹线与真实轨迹基本重合,沿任意路径SIF数值几乎相等,且裂纹扩展寿命预测值与试验寿命极其接近,误差只有2.4%。The prediction of real and extreme irregular crack front growth paths directly determines the accuracy of evaluating residual fatigue life of structures.A method for studying the distribution of stress intensity factor(SIF)along the extremely irregular crack fronts was developed by using a notched member,which was geometrically most similar to an engineering structure,as the cracked body.Firstly,the local curvature changes caused by convex,concave,and small curvature radii along the crack front were characterized by high-resolution spline curves.Then,based on the sub-model method combined with adaptive meshing technique,the growth trajectory of irregular crack front was iteratively simulated to obtain the irregular crack propagation law.Finally,by comparing the predicted crack geometry with the experimentally measured crack location,size,and other information,the reliability of crack propagation driving force simulated by Franc3D was verified through examples.The results show that the predicted crack front trajectory basically coincides with the actual,and the SIF values along any normalized growth path are basically equal.The predicted residual life is very close to the experimental life,with an error of only 2.4%.

关 键 词：应力集中 自适应网格 子模型法 不规则裂纹前沿 生长规律 

分 类 号：TH114[机械工程—机械设计及理论]