Experimental and analytical analyses of the bonding performance of CFRP–wood interface

Abstract

The mechanical properties of the bonding interface between carbon fiber-reinforced polymers (CFRPs) and wood are key to study how the wood structure is strengthened by CFRPs. The interfacial bonding shear stress–slip relationship model and the interfacial bearing capacity model are important theoretical bases and practical references to investigate this strengthening mode. To study the influence of different factors on the mechanical properties of the bonding interface, and establish the bearing capacity model and the bond slip relationship model of the CFRP–wood interface, the mechanical properties of the interface between CFRPs and wood were evaluated by testing six groups of CFRP–wood specimens under double shear. The evolution of the CFRP strain and the interfacial bonding shear stress was analyzed to obtain the bond shear stress–slip relationships. Furthermore, the influence of the CFRP bond length and width on the interfacial bonding performance was discussed. The results show that an interfacial bond shear stress process was transferred from the loading end to the free end with an established effective bond length. The expressions for strain distribution in the CFRP sheets during the entire loading process were then calculated from the force analysis of the microsections of the bond interface and the regression analysis of the results. The data are in good agreement with the test curves. Furthermore, the CFRP–wood interface bonding bearing capacity model, effective bond length model, and interface bonding shear stress–slip relationship model were proposed based on the existing theoretical model and its comparison with the experimental results. The errors between the values predicted by the effective bond length model and the interface bond bearing capacity model and the experimental values are less than 18%. The curves predicted by the interface bond shear stress–slip model are in good agreement with the experimental curves.