Insight of Salt Spray Corrosion on Mechanical Properties of TA1-Al5052 Self-Piercing Riveted Joint

Self-piercing riveted (SPR) joints in automobiles inevitably suffer from corrosion damage and performance reduction. In this work, the influence of salt spray corrosion on the mechanical properties of TA1-Al5052 alloy SPR joints was studied. The TA1-5052 SPR joints were prepared and salt spray tests were carried out for different durations. The static and fatigue strengths of the joints after salt spray corrosion were tested to analyze the effect of salt spray duration on the performance of the joints. The results show that the joints’ static strength and fatigue strength decrease with prolonged salt spray time. The salt spray duration affects the joint’s tensile failure mode. The tensile failure without corrosion and with a short salt spray time is the fracture failure of the lower aluminum sheet, and the tensile failure of the joints after a long time of salt spray corrosion is the failure of the rivets. The fatigue failure form of the SPR joint is the formation of fatigue cracks in the lower aluminum sheet, and salt spray time has little effect on the fatigue failure form. Salt spray corrosion can promote the initiation and propagation of fatigue cracks. The fatigue crack initiation area is located at the boundary between the lower aluminum sheet and the rivet leg. The initiation of cracks originates from the wear zones among the sheet metal, rivets, and salt spray particles

Insight of Salt Spray Corrosion on Mechanical Properties of TA1-Al5052 Self-Piercing Riveted Joint

Self-piercing riveted (SPR) joints in automobiles inevitably suffer from corrosion damage and performance reduction. In this work, the influence of salt spray corrosion on the mechanical properties of TA1-Al5052 alloy SPR joints was studied. The TA1-5052 SPR joints were prepared and salt spray tests were carried out for different durations. The static and fatigue strengths of the joints after salt spray corrosion were tested to analyze the effect of salt spray duration on the performance of the joints. The results show that the joints’ static strength and fatigue strength decrease with prolonged salt spray time. The salt spray duration affects the joint’s tensile failure mode. The tensile failure without corrosion and with a short salt spray time is the fracture failure of the lower aluminum sheet, and the tensile failure of the joints after a long time of salt spray corrosion is the failure of the rivets. The fatigue failure form of the SPR joint is the formation of fatigue cracks in the lower aluminum sheet, and salt spray time has little effect on the fatigue failure form. Salt spray corrosion can promote the initiation and propagation of fatigue cracks. The fatigue crack initiation area is located at the boundary between the lower aluminum sheet and the rivet leg. The initiation of cracks originates from the wear zones among the sheet metal, rivets, and salt spray particles

Developing a self-piercing riveting with flange pipe rivet joining aluminum sheets

This paper proposes a self-piercing riveting (SPR) method which uses a flange pipe rivet. This joining technology can solve the problems of oblique rivet and incorrect rivet position which are usually found in the SPR with a pipe rivet. The lap shear strength of the joint with a flange pipe rivet is higher than that of a joint with a conventional rivet. In this research, a flange pipe rivet was placed between two sheets with a force applied to the top sheet by a punch riveting machine. The flange pipe rivet moved downward along with the top sheet to induce appropriate bending and form a mechanical interlock in both sheets. Finite element (FE) analysis of the SPR with a flange pipe rivet was done by DEFORM software. The simulated joint cross-section shapes were observed, and the influence of the flange pipe rivet parameters on joint quality was analyzed. Simultaneously, some riveting experiments on joining aluminum sheets were conducted taking into consideration different rivet heights and chamfer angles. The results show that the joining surface is smooth and the simulated joint cross-section shapes are in good agreement with the experimental results. The joining property with a chamfer angle of 45° and a rivet height of 5 mm is found to be the best in joining the Al6063 aluminum alloy sheets with a thickness of 2.4 mm by using the SPR with a flange pipe rivet

Effect of Stitching, Stitch Density, Stacking Sequences on Low-Velocity Edge Impact and Compression after Edge Impact (CAEI) Behavior of Stitched CFRP Laminates

Low-velocity edge impact and compression after edge impact (CAEI) behavior of stitched carbon-fiber-reinforced plastic (CFRP) laminates were experimentally investigated in the paper. Five groups, including three stacking sequences (P1, P2, P3) and two stitch densities (stitch space × stitch pitch is 10 mm × 10 mm and 15 mm × 15 mm) of stitched/unstitched CFRP laminates, were prepared by the VARTM technique and subjected to low-velocity edge impact and compression after edge impact experiments. The damage of CFRP laminates was detected by optical observation and micro-CT. The effects of stitching, stitch density, stacking sequences and impact energy on properties of edge impact and CAEI were discussed. The results show that the damage of edge impact of stitched laminates is smaller than that of unstitched laminates. The main failure mode of CAEI of the unstitched laminates is delamination and that of the stitched laminates is global buckling. The addition of stitches can effectively improve the edge impact resistance and damage tolerance of CFRP laminates. Compared with the unstitched laminates with the same stacking sequence, the peak impact force of the laminates with stitch density 15 mm × 15 mm increases by 5.61–12.43%, and the increase in residual compression strength is up to 5–20.9%. The peak impact force of the laminates with stitch density 10 mm × 10 mm increases by 8.1–31.4%, and the increase in residual compression strength is up to 24.2–27%. Compared with the other two stacking sequences (P1 and P2), the stacking sequence P3 has excellent resistance of edge impact and CAEI properties