An improved simplified model of self-piercing riveted joints for predicting quasi-static mechanical behavior of steel–aluminum hybrid components

Abstract

The problem that the existing models could not accurately predict sheet deformation modes in the riveting area led to low prediction accuracy in crash simulations for steel-aluminum hybrid structural components in vehicle bodies. An improved simplified model with rigid and washer-processed elements (CONSTRAINED_SPR4_RIGWE) is proposed to calibrate the mechanical behavior of self-piercing riveted (SPR) joints based on the *CONSTRAINED_SPR4 model. The diameters of rigid and washer-processed elements in the upper and lower sheets were based on the diameters of the rivet and bottom of the SPR joint, respectively; the influence domain in the joint was determined by the diameter of the rivet cap. The parameters of the two models were calibrated using the experimental results of the lap shear, pull-out, mixed tension–shear, and peeling tests, as well as the parameters from the detailed three-dimensional model. Compared with the *CONSTRAINED_SPR4 model, the CONSTRAINED_SPR4_RIGWE model had a higher stiffness value for pull-out and peeling specimens, which was closer to the experimental result. T-shaped and C-shaped structural components of DP590 high-strength steel and AC43500-T7 cast aluminum sheets were prepared using SPR joints. For the T-R4 component, the absolute prediction error of the CONSTRAINED_SPR4_RIGWE model in terms of the energy absorption was lower than that of the *CONSTRAINED_SPR4 model, with the former being 2.48 % and the latter being 16.53 %. For the C-R8 component, the absolute maximum prediction errors of the CONSTRAINED_SPR4_RIGWE model in terms of peak force, failure displacement, and energy absorption increased from 16.82 % to 149.42 %, as compared with those of the *CONSTRAINED_SPR4 model.