Comparative Study of Steel-Aluminum Mechanical Joints: Self-Piercing Riveting and Clinching 2019-01-1115
Nowadays manufacturing lightweight vehicles not only pursues more excellent structural performance of materials, but also puts effort on selecting or developing reliable technologies for joining dissimilar materials to offer sufficient structural stiffness and crashworthiness. Among the combinations of dissimilar materials, steels and aluminum alloys are the most prevalent that are applied to achieve viable and sustainable products. Joining processes of mechanical, chemical, thermal or a hybrid type can be selected to join steel and aluminum alloy together, which could become complicated considering the manufacturing conditions, the cost and so on. Self-piercing riveting (SPR) and clinching have many advantages, and are quite suitable for manufacturing steel-aluminum joints. SPR has good mechanical and fatigue strength while clinching has a lower manufacturing cost.
The present work tends to compare the dynamic effect of the SPR and the clinching joint of the same material combination. The substrates in this investigation are aluminum 5182-O and steel DX51D+Z. The static, dynamic behaviors and the failure modes of the SPR and the clinching joint are characterized with lap-shear and coach-peel tests. Influence of the strain-rate dependent mechanical behavior of the substrates on the joints is examined by the means of finite element modeling, which helps improve the prediction of energy absorption of the joints under impact loading.
Considering the realistic baking process in painting shop, the deforming and hardening effects on the SPR and the clinching joint induced by baking are also studied. The specimens are heated in the oven in 180 oC for 30 minutes and cooled down in the air. The SPR and the clinching joint before and after the baking process are compared in terms of the mechanical behavior and the cross-section.