Rapid multi-material joining via flow drill screw process: experiment and FE analysis using the coupled Eulerian‒Lagrangian method

This paper is concerned with experiments and finite element (FE) simulations using the coupled Eulerian‒Lagrangian (CEL) method for multi-material joining by the flow drill screw (FDS) process. The FDS joining experiments involved various combinations of aluminum alloys (Al6061-T6 2.0t and Al6063-T6 2.0t), and steel (SPRC45E 1.6t) sheets. During the FDS joining, thermocouples and a thermal imaging camera, FLIR, were used to measure the elevated temperature near the joint. Cross-sections of the multi-material joint specimens were prepared to check the joining quality and the deformed shape of the materials. To consider the complexity of the joining process and convergence issue of numerical simulation, the FE modeling approach for the FDS joining was constructed based on the CEL method using the ABAQUS/Explicit, considering the strain rate and thermal softening dependent strain hardening of each material. From the comparison of experimental and FE simulation results, the reliability of the FE modeling was validated, revealing the predictability of the deformed shape was 90% or more, especially in terms of the bushing length. Furthermore, it was confirmed that the proposed modeling approach can accurately describe the temperature history and peak values during rapid joining.