The Impact of Hole Defects on Fatigue Crack Growth Path and Life of Aluminum Alloy Welded Joints
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 calculat-ed for different hole diameters,transverse distances and longitudinal distances.The calculation results show that:due to the presence of the hole,K Ⅱ increases 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°.
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