Modeling and process optimization for flow drilling fusion screw joints between CF-PPS composites and 2A12-T4 aluminum alloy

To address the challenge of heat management and joint quality control in flow drilling fusion screw (FDFS) joints between carbon fiber reinforced polyphenylene sulfide (CF-PPS) composites and 2A12-T4 aluminum alloy, a segmented time-dependent thermal input model is proposed that incorporates screw-feed kinematics and laminate stacking configurations. Unlike conventional uniform models, the proposed model captures the spatial and temporal heterogeneity of heat generation in composite-metal hybrid structures. Orthogonal experiments revealed an inverse relationship between screw rotational speed, axial pressure, and heat generation. Thread engagement length increased with heat input, while shear strength reached its maximum at intermediate heat levels. An appropriate heat input balanced material plasticization and structural integrity, thereby reducing porosity and thermal degradation. These results clarify the thermo-mechanical coupling behavior in FDFS joints and provide guidance for improving the reliability of composite-metal hybrid connections in aerospace structures.