Numerical and parametric study on fracture behaviour and effect of friction on resistance of aluminium alloy shear connections

Fastener pre-tension is commonly used in the practical cases of aluminium alloy bearing-type connections with friction provided by treated surfaces. However, research on the effect of friction on the ultimate resistance is currently limited. In this paper, a numerical investigation on the structural performance and design of aluminium alloy double shear connections fastened by preloaded stainless steel swage-locking pins is presented. Finite element (FE) models were developed using Abaqus explicit dynamic packages and validated against the tests conducted previously. Prior to the numerical modelling of shear connections, the framework of aluminium alloy material properties has been studied. In order to simulate the full-range stress-strain relations and the failure of the tested aluminium alloys, two damage models were evaluated. The adopted model was then used to simulate the fracture occurred at the peak load or the post-peak stage in the double shear connection tests, and investigate their failure mechanism of bearing, shear-out and end-splitting. Upon validation, an extensive parametric study of 330 shear connections was conducted to investigate the effect of friction and pin configuration on the structural performance of shear connections made of different aluminium alloy grades. The values of the friction and pin hole resistance at the ultimate loads were comprehensively discussed. The numerically derived ultimate resistances were also compared with the current design equations, which were shown to provide conservative and scattered results due to the lack of consideration of the friction effect. A new design method was proposed with the friction effect incorporated, resulting in accurate predictions of ultimate resistance for aluminium alloy shear connections with preloaded stainless steel swage-locking pins.

Automated summary

In this paper, a new design method is proposed to accurately predict the ultimate resistance of aluminium alloy shear connections with preloaded stainless steel swage-locking pins. The structural performance of shear connections made of different aluminium alloy grades was extensively studied, and the effect of friction and pin hole resistance at ultimate loads was discussed.