Fatigue behaviour of butt-lap friction stir welded joints used with aluminum bridge decks

Trimech, Mahmoud; Annan, C.-D.; Walbridge, Scott; Maljaars, Johan

doi:10.1016/j.istruc.2023.03.151

Cited by 6 publications

(1 citation statement)

References 39 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Several researchers found that the size and morphology of the hook defect affect the crack growth state in the tensile shear test, which is macroscopically manifested as a change in the fracture location of the joint [5][6][7]. Importantly, the existence of the hook defect is a key factor in reducing fatigue strengths because the tip of a hook defect always causes a change in stress concentration, providing a desirable site for fatigue crack initiation, and also because the hook defect reduces the effective thickness of the upper plate and the effective lap width of the joint, facilitating crack propagation by offering a suitable orientation, and thereby diminishing the load-bearing capacity of the welded parts [8][9][10]. In order to ensure safety, EN ISO 25239-5:2020 [11] also stipulates that the size of the hook defect should be less than 0.1 t (where t is the thickness of the upper plate), which seems to be so large that it loses its guiding significance in actual production.…”

Section: Introductionmentioning

confidence: 99%

Comparative Analysis of Three Different Probe Designs for Reducing Hook Defects in FSW of AA6005-T6 Aluminum Alloy

Qin,

Zhang,

Bian

et al. 2024

Metals

View full text Add to dashboard Cite

Hook defects are common in FSW butt–lap joints, resulting in a significant safety hazard for the parts that suffer cyclic load. In this study, a numerical simulation based on the Euler–Lagrange coupling method was conducted to investigate the formation process of hook defect during FSW of AA6005-T6 aluminum alloy. The simulation results were validated with experimental data, showing good agreement. The formation of the hook defect is caused by the threads on the probe promoting material flow in the thickness direction. In order to further study the effect of probe morphology on hook defects, three kinds of probe models with different morphology were established and numerically simulated by the CEL method. The simulation results show that all three kinds of probes can reduce the size of the hook. The welds obtained using the left–left probe (LLP) and the three-plane probe (TPP) both exhibit void defects, while the welds obtained by a right–left probe (RLP) have no internal void defects. The experimental results show the same characteristics as the simulation results, and the size of the hook defect is reduced to 58 μm.

show abstract