基于ABAQUS与FRANC 3D联合仿真的方法，对2024-T4铝合金搅拌摩擦焊接头预制裂纹于不同部位的紧凑拉伸试样进行裂纹扩展分析以及寿命预测，并深入分析不同部位裂纹扩展行为存在差异性的原因. 结果表明，随着裂纹长度的不断延长，裂纹尖端应力强度因子随之增大，且裂纹向前扩展路径基本沿直线扩展，ABAQUS与FRANC 3D联合仿真方法分析不同部位的裂纹尖端应力强度因子和裂纹扩展路径的理论计算和试验结果基本吻合，验证了分区域进行联合仿真的模型精度满足要求.不同部位裂纹扩展试样寿命预测结果与试验结果的相对误差均在5%左右，对焊接接头分区域联合仿真进行寿命预测是准确可行的. 裂纹位于不同部位的扩展试样断口处的疲劳辉纹间距不同导致预制裂纹于3个部位的疲劳寿命由低到高为：热影响区、垂直于焊缝方向、焊核区.
Based on the method of ABAQUS and FRANC 3D co-simulation, the crack growth analysis and life prediction were carried out on the compact tensile specimens with precracks in different zones of 2024-T4 aluminum alloy friction stir welding (FSW) joints, and the causes of the differences in crack propagation behavior in different zones were analyzed. The results showed that the crack tip stress intensity factor increased with the growth in crack length, and the crack forward expansion path basically expanded along the straight line. ABAQUS and FRANC 3D joint simulation method analysis of different areas of crack tip stress intensity factor and crack propagation path basically consistent with the theoretical calculation and test results, verifying that the model accuracy of the joint simulation by subregion is satisfactory. The relative errors of the life prediction results in different zones and the test results are about 5%, so it is accurate and feasible to predict the life of the joint by regional co-simulation. The fatigue striation spacing at the crack propagation fracture in different zones is different, resulting in the fatigue life of the prefabricated crack in three zones from low to high: the heat affected zone, perpendicular to the weld direction, and the weld core zone.
[1] 杨炳鑫, 马运五, 山河, 等. 2Al2-T4铝合金自冲摩擦铆焊接头力学行为研究[J]. 航空学报, 2022, 43(2): 625111
Yang Bingxin, Ma Yunwu, Shan He, et al. Mechanical performance of friction self-piercing riveted joint for 2A12-T4 aluminum alloy[J]. Acta Aeronautica ET Astronautica Sinica, 2022, 43(2): 625111
[2] 韩丽娟, 李小欣, 李继承. 焊丝对2A12铝合金焊接接头组织和力学性能的影响[J]. 机械工程材料, 2015, 39(3): 32-35
Han Lijuan, Li Xiaoxin, Li Jicheng. Effects of welding wires on microstructure and mechanical properties of 2A12 aluminum alloy welded joints[J]. Materials for Mechanical Engineering, 2015, 39(3): 32-35
[3] Xiao K, Liu P, Sun L S Y, et al. Study on fatigue crack propagation and fracture characterization of 7050-T7451 friction stir welded joints[J]. Journal of Materials Engineering and Performance, 2021, 30(8): 5625-5632.
[4] Zhang L, Zhong H L, Li S C, et al. Microstructure mechanical properties and fatigue crack growth behavior of friction stir welded joint of 6061–T6 aluminum alloy[J]. International Journal of Fatigue, 2020, 135: 105556.
[5] Wang L, Hui L, Zhou S, at al. Effect of corrosive environment on fatigue property and crack propagation behavior of Al 2024 friction stir weld[J]. Transactions of Nonferrous Metals Society of China, 2016, 26(11): 2830-2837.
[6] Barrallier D. Friction stir welding of AZ31 magnesium alloy rolled sheets: Influence of processing parameters[J]. Acta Materialia, 2009, 57(2): 326-334.
[7] Wu D, Li W Y, Liu X C, et al. Effect of material configuration and welding parameter on weld formability and mechanical properties of bobbin tool friction stir welded Al-Cu and Al-Mg aluminum alloys[J]. Materials Characterization, 2021, 182: 111518.
[8] Tra T H, Okazaki M, Suzuki K. Fatigue crack propagation behavior in friction stir welding of AA6063-T5: Roles of residual stress and microstructure[J]. International Journal of Fatigue, 2012, 43: 23-29.
[9] Lezcano R, Rodríguez C, Peñuelas I, et al. Effect of mechanical mismatching on the ductile-to-brittle transition curve of welded joints[J]. Engineering Failure Analysis, 2009, 16(8): 2576-2585.
[10] Rao H M, Jordon J B, Ghaffari B, et al. Fatigue and fracture of friction stir linear welded dissimilar aluminum-to-magnesium alloys[J]. International Journal of Fatigue, 2016, 82(3): 737-747.
[11] Sarikka T, Ahonen M, Mouginot R, et al. Microstructural, mechanical, and fracture mechanical characterization of SA 508-Alloy 182 dissimilar metal weld in view of mismatch state[J]. International Journal of Pressure Vessels and Piping, 2016, 145: 13-22.
[12] Dai Q L, Liang Z F, Chen G Q, et al. Explore the mechanism of high fatigue crack propagation rate in fine microstructure of friction stir welded aluminum alloy[J]. Materials Science & Engineering A, 2013, 580: 184-190.
[13] 王磊, 赵新华, 张璐, 等. 力学失配FSW接头拉伸变形的光学原位分析[J]. 焊接学报, 2020, 41(1): 23-28
Wang Lei, Zhao Xinhua, Zhang Lu, et al. Optical in situ analysis of tensile deformation of mechanically mismatched FSW joints[J]. Transactions of the China Welding Institution, 2020, 41(1): 23-28
[14] Zhou J, Sun Y, Shu H, et al. Effect of laser peening on friction and wear behavior of medical Ti6Al4V alloy[J]. Optics & Laser Technology, 2019, 109: 263-269.
[15] Liu H J, Sun J J, Jiang T, et al. Research on rolling contact fatigue of an ultra-high carbon steel[J]. Acta Metall Sinica, 2014, 50(12): 1446-1452.
[16] Achintha M, Nowell D, Fufari D, et al. Fatigue behaviour of geometric features subjected to laser shock peening: Experiments and modelling [J]. International Journal of Fatigue, 2014, 62: 171-179.
