A novel joining technology for metal and polymer sheets

This paper introduces a novel joining process for producing hybrid metal-polymer joints. The process, called hole hemming, involves deforming the metal sheet to establish a mechanical interlock with the polymer sheet, requiring neither heating nor auxiliary elements. The applicability of this process is tested for joining aluminum and polycarbonate (PC) sheets. Initially, an analytical design method is presented to achieve a connection without failure and with a mechanical interlock. Subsequently, the accuracy of the predictions is assessed through experiments and finite element simulations, employing the modified Mohr-Coulomb criterion for the prediction of ductile damage. Additionally, a new design for hole-hemmed joints, involving the incorporation of branches in the hole of the outer sheet, is introduced to expand the process window of this novel joining technology. Finally, the mechanical behavior of four different types of hybrid hole-hemmed joints (HHH joints) are evaluated through single-lap shear tests. The results show that the hole hemming process can successfully join AA6082-T4 and PC sheets, validating the proposed designs and ideas. The new hybrid joints demonstrate a maximum force and displacement of 1.6 kN and 12.9 mm, respectively, in the shear test, indicating significant potential of the proposed technology for joining metal and polymer sheets.