Background: Self-piercing riveting (SPR) is a new performing technology able to joint several kinds of metal and\nnon-metal supports together. The combined effect of joint configuration and environmental conditions could have\ndetrimental effect on the ageing effect on mechanical behaviour of dissimilar metal SPR joints.\nMethods: The joining of dissimilar materials, such as steel and aluminium, realized by self-piercing riveting (SPR)\ntechnique was studied to evaluate the ageing effects on its mechanical behaviour in critical environmental conditions.\nThe investigation was carried out on symmetrical or unsymmetrical joints at varying total thicknesses (i.e. 2.0, 2.5 and\n3.0 mm). The joint resistance was determined by single-lap shear tests. A design of experiment (DoE) has\nbeen performed by using Minitab�® followed by the statistical analysis (ANOVA) of the experimental data.\nLong-term ageing tests in salt spray environment were performed to evaluate the durability of the mechanical joint.\nResults: The experimental results evidenced that the corrosion degradation phenomena influenced significantly both the\nperformance and failure mechanisms of the joints; also, the joint configuration is a significant factor for the corrosion\neffect. In the salt spray, the aluminium sheet undergoes a noticeable degradation due to galvanic Al/Fe corrosion. The set\ncharacterized by thinner aluminium sheet evidenced a gradual reduction of the mechanical strength with\nincreasing ageing time due to the prevalence of thinning induced by aluminium corrosion. Instead, for S10-A15 samples\n(characterized by a thicker thickness of aluminium sheet) during the first 7 weeks, stable mechanical performances were\nobserved.\nConclusions: The experimental results evidenced that the corrosion degradation phenomena influence significantly both\nperformances and failure mechanisms of SPR joints. Furthermore, the durability of the SPR joint is strongly affected by the\njoint configuration, and the best results were observed in the unsymmetrical joint with thicker aluminium sheet.
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