孔状缺陷对铝合金焊接接头疲劳裂纹扩展路径及寿命的影响  

The Impact of Hole Defectson Fatigue Crack Growth Path and LifeofAluminum Alloy Welded Joint

作　　者：管锋[1] 张锦洲[1] 姬世青 GUAN Feng;ZHANG Jinzhou;JI Shiqing(College of Mechanical Engineering,Yangtze University,Jingzhou 434023,Hubei,China)

机构地区：[1]长江大学机械工程学院,湖北荆州434023

出　　处：《昆明理工大学学报（自然科学版）》2024年第4期170-178,共9页Journal of Kunming University of Science and Technology(Natural Science)

基　　金：国家自然科学基金项目(51974035,U1262108);油气藏地质及开发工程国家重点实验室(西南石油大学)开放基金(PLN2022-17);大学生创新创业项目(Yz2021117)。

摘　　要：为了研究孔状缺陷对焊接结构中疲劳裂纹扩展及寿命的影响,以6061铝合金为研究对象,基于NASGRO模型,利用ABAQUS和FRANC3D进行联合仿真,经试验验证结果可信,计算了不同孔径、横向距离、纵向距离时CT试样的疲劳寿命和裂纹偏转角度.计算结果表明:由于孔的存在,裂纹扩展时KⅡ显著增加,在裂纹扩展过程中Ⅱ型裂纹扩展发挥了更大的作用;当孔位于裂纹扩展路径附近时,孔边缘会有比较大的应力集中,从而吸引裂纹向孔的方向偏转;当孔径较小时可以起到一定的延寿作用,但随着孔径的增加疲劳寿命快速下降,孔径为4 mm时疲劳寿命最大减少33%,裂纹最大偏转角48°;随着纵向距离的减少疲劳寿命不断减少,纵向距离为4 mm时疲劳寿命减少53%,裂纹最大偏转角44°;随着横向距离的减少疲劳寿命不断减少,但横向距离的影响相对较小,横向距离为6 mm时疲劳寿命最大减少20%,裂纹最大偏转角39.6°.To study the influence of hole defectson fatigue crack extension and life in welded structures,With 6061 aluminum alloy as the research object,based on the NASGRO model,joint simulation using ABAQUS and FRANC3D,the test results are credible,the fatigue life and crack deflection angle of CT specimens were calculated for different hole diameters,transverse distances and longitudinal distances.The calculation results show that:due to the presence of the hole,KⅡincreases significantly during crack expansion,and type II crack expansion plays a greater role in the crack expansion process;when the hole is located near the crack expansion path,there is a relatively large stress concentration at the edge of the hole,which attracts the crack to deflect in the direction of the hole;when the hole diameter is small,it can play a certain role in life extension,but with the increase of the hole diameter the fatigue life decreases rapidly,and the maximum fatigue life decreases 33%when the hole diameter is 4mm,and the maximum crack deflection angle is 48°;the fatigue life decreases continuously with the decrease of longitudinal distance,and the fatigue life decreases 53%when the longitudinal distance is 4mm,and the maximum crack deflection angle is 44°;the fatigue life decreases continuously with the decrease of transverse distance,but the influence of transverse distance is relatively small,and the maximum fatigue life decreases 20%with the transverse distance,and the maximum crack deflection angle is 39.6°.

关 键 词：孔状缺陷 铝合金焊接接头 数值模拟 疲劳裂纹扩展 疲劳寿命 

分 类 号：TG407[金属学及工艺—焊接] O346.1[理学—固体力学]