Effect of adhesive ductility and joint configuration on the tensile-shear behaviors of friction stir spot weld bonding joints

ABSTRACT

This paper introduced a hybrid joining system including friction stir spot welding (FSSW) and adhesive bonding, named friction stir spot weld bonding (FSSWB). In order to avoid adhesive layer carbonization, FSSWB was processed by flow-in method. The aim of this study was to evaluate the effect of adhesive ductility and joint configuration on the tensile-shear performances of AA6061 aluminum alloy. Two types of adhesives were considered: brittle epoxy (AV138) and ductile epoxy (Araldite 2015). Besides, hybrid joints involve three types of joint configurations (AV138, Araldite 2015 and dual adhesive). A finite element (FE) model of hybrid joints failure process was established based on the extended finite element method (XFEM) and cohesive zone model (CZM). The tensile-shear failure load (TSFL) prediction values and joint failure process were in good agreement with the experiments. Compared to FSSW, the TSFL values for the three types of hybrid joint increased by 166.5%, 294.8% and 173.8% respectively. In addition, the stresses at the hook tip of the three hybrid joints were decreased by 85.56%, 79.31% and 83.67%. From the study, it was found that the use of ductile adhesives at two sides of joint was more helpful to increase the load-bearing capacity of FSSWB joints.

KEYWORDS:

• Friction stir spot weld bonding
• joint design
• tensile-shear failure load
• extended finite element method
• cohesive zone model
• failure mode

Notes on Contributions

Conceptualization, Y.G.; data curation, G.Y. and W.Z.; funding acquisition, X.C.; investigation, G.Y.; methodology, G.Y. and X.C.; project administration, X.C.; writing—original draft, G.Y.; writing—review & editing, X.C. All authors have read and agreed to the published version of the manuscript.

Acknowledgements

The authors acknowledge the use of the facilities within the State Key Laboratory of Automobile Simulation and Control of Jilin University and the Changchun University of Technology.

Conflicts of Interest

The authors declare no conflict of interest; Graduate Innovation Fund of Jilin University [101832020CX128]; National Key Research and Development Plan of China [2016YFB0101601-7]; Jilin Province School Co-construction Project [SXGJSF2017-2-1-5];

Additional information

Funding

This research was financially funded by the National Key Research and Development Plan of China (Grant No. 2016YFB0101601-7), Jilin Province School Co-construction Project (Grant No. SXGJSF2017-2-1-5) and Graduate Innovation Fund of Jilin University (101832020CX128).