Joining technology of carbon fiber reinforced polymer (CFRP) using copper wire and adhesive

Abstract This paper investigates a novel approach for joining carbon fiber reinforced polymer (CFRP) composites, aiming to mitigate fiber continuity disruptions and stress concentrations typically associated with conventional mechanical joining methods such as bolts and rivets. Specifically, the study examines the effects of copper wires (diameter: 0.25 mm), arranged horizontally and vertically on the CFRP surface, on adhesive bonding performance under curing conditions of 170 °C for 15 min. Single-lap shear tests and optical microscopy analyses were conducted to evaluate the influence of wire orientation and curing conditions on interfacial strength, adhesive mechanisms, and failure modes. Vertically aligned copper wires achieved the highest average shear strength of 20 MPa, representing a maximum load increase of 439.74% compared to adhesive-only joints. Surpassing horizontal and no-wire samples. This improvement is attributed to enhanced adhesive infiltration and mechanical interlocking at the interface, leading to more cohesive failure within the adhesive layer. The results demonstrate that copper wire orientation significantly impacts adhesive penetration, interface quality, and fracture characteristics. Furthermore, optimized curing conditions improve adhesive stability and reduce interfacial degradation, reinforcing the tendency toward cohesive failure. This study provides quantitative and practical insights into copper wire-reinforced bonding mechanisms, facilitating advancements in composite electronics and structural applications.