School of Automotive Studies,Tongji University,Shanghai 201804, China
TakingSt16 and 6061 aluminum alloy tubes as objects, the feasibility of using a novel plastic joining method to connect these two thin-walltubes was investigated. A finite element model was built using the Abaqus software, and a special moldfor plastic joining of thin-walled tubes was presented. Experiments of tubes plastic joining were performed to verify the precision of the finite element model. The influence of the relative free length of the tube endgap between the die and the tube, and the gap between the mandrel and the tube on the formability of the joint adopted in the plastic compressionjoiningprocess was emphasized. The results demonstrated that the method of plastic joining by compression was a suitable approach for thin-walled tubesof dissimilar materials. The key technology was that the free length of the tubes and the gap between molds and tubes should be correctly designed.The plastic deformation of the two tubes in the compression instability was compatible.Theamountof deformation and the directionof the movement of the wrinkles should be compatible so that the two wrinkles could contact tightly. For the St16/AA6061 tubesinvestigated,the prerequisite condition for a success joining was that the relative free length should located between 1.250 and 1.625. The gap between the tube and the dieshould be between 0.07 and 0.20 times of the thickness of the tube while that between the tube and the mandrel should be between 0.07 and 0.27 times of the thickness of the tube.