An investigation of residual stress distribution in friction drilling of AA 7075 sheets by finite element modeling

The significance of sheet metal drilling within industrial applications is widely recognized, particularly for its critical role in creating durable connections in sheet components. This process, especially when implemented through friction drilling, not only minimizes material waste by generating connecting flanges bush shape but also enhances the robustness of the connections. In this study, we used the ABAQUS finite element software (FEM) to simulate and design the friction drilling process on sheets of three different thicknesses, employing three rotational speeds and three feed rates. The analysis was conducted using Design Expert statistical software, which integrated response surface methodology (RSM) and data analysis to thoroughly investigate the process forces. Aluminum AA 7075 was selected for the study due to its extensive use in the automotive, manufacturing, military, and aerospace organizations, highlighting its industrial relevance. The findings suggest that optimizing the machining force leads to more favorable conditions within the process. The optimal parameters were determined to include the highest rotational speed, the lowest feed rate, and the smallest sheet thickness. These conditions promote higher temperatures that facilitate better material flow. An increase in thickness was also found to correlate with higher temperatures. Additionally, the study addressed the significant industrial challenge of residual stresses and their effects on component defects, a topic not previously explored through finite element simulations in this context. This research contributes new insights into the implications of residual stresses in various directions for friction drilling processes.