Load-Bearing Capacities and Fracture Modes of Self-Piercing-Riveted, Adhesive-Bonded and Riv-Bonded Aluminum Joints at Quasi-Static and Cyclic Loadings

The load-bearing capacities of (i) self-piercing-riveted, (ii) adhesive-bonded and (iii) hybrid riv-bonded lap joints of commercial 1.5-mm-thick EN AW-6016-T4 sheets were compared under both quasi-static and cyclic shear-tensile loads. The joints were heat-treated to cure the adhesive and to peak-age the aluminum alloy. The joint quality/integrity was assessed based on characteristic cross-sectional features and hardness maps. Riveted joints showed notably lower static strength and fatigue performance than riv-bonded joints. Hence, the adhesive layer provided the main contribution to both the static and the cyclic load-bearing capacities of riv-bonded joints, whereas rivets contributed only little. However, if bonding was insufficient the potential capacity of the joints could not be exploited. Under quasi-static loading fracture occurred at the joint; therefore, joints of high quality/integrity were important. Even under cyclic loading at high load amplitudes fracture occurred at the joint, but at comparatively low load amplitudes fracture rather occurred at the sheets next to the joint. Hence, the joint quality/integrity mainly determines the static fracture and the low-cycle fatigue fracture, whereas the sheet properties mainly determine the high-cycle fatigue fracture.