The effect of staged process parameters for flow drill screws on the strength of the connection between carbon fiber-reinforced plastic and aluminum alloy

This article applies flow drill screws (FDS) technology to the connection of dissimilar materials, carbon fiber-reinforced plastic (CFRP) and 6061-T6 aluminum alloy (AA6061-T6), and proposes a method to study the influence of FDS process parameters on the strength of the connection in stages. Based on this method, the optimal process parameters for the connection of this type of plate are explored. Firstly, the mathematical analysis of the process in each stage is conducted, and then the different process parameters in different stages are grouped and tested for the strength of the joint. The optimal process parameters obtained from the previous stage are input into the next stage for further testing, resulting in the highest shear connection strength of 5.98 kN for the FDS connection of CFRP and AA6061-T6 plates. The experimental results show that the influence of different process parameters on the strength of the joint varies in different stages. To improve the connection strength, high speed and low feed force should be selected in the second stage, low speed and low feed force should be selected in the third stage, and the tightening torque should be reasonably selected in the fourth stage.