Improving shear strength of carbon fiber composite honeycombs with the surface microprinting technology

Carbon fiber reinforced plastics (CFRP) honeycomb structures are widespreadly applied in aerospace and aeronautical sectors due to their high specific strength and stiffness. However, the low shear strength of CFRP honeycomb structures limits its further application. In this paper, surface treatment methods for improving surface bonding strength of CFRP plates are studied. The results show that the surface microprinting technology (SMT) is a recommended surface treatment method for CFRP panels and can be used to improve the bonding strength among facesheet-core (between facesheets and cores) and core-core (among the honeycomb walls) of honeycomb sandwich structure. Meanwhile, the mechanical model of CFRP honeycomb structure is established, the theoretical prediction formula of shear strength of CFRP honeycomb structure is explicitly deduced. And further analysis and verification were conducted compared to shear tests. The strengthening mechanism of the surface treatment method is then revealed. The experimental results show that the treatment method of SMT can greatly improve the shear strength of CFRP honeycomb sandwich structure and provide technical database and guidelines for its application in the aerospace and aeronautical fields.