Experimental study and analysis on bonding strength of CFRP-wood interface

In order to study the factors that influence the bonding capacity of the bonded interface formed between carbon fiber reinforced polymers (CFRP) and wood, 10 groups (30 total samples) of CFRP-wood specimens were designed. The development law of CFRP plate strain was analyzed, and the effects of the bonded width and length of CFRP sheet to the wood as well as the damage rate of wood on the bonding capacity of the interface were discussed. The test results showed that the stress was gradually transmitted from the loaded end to the free end of the sample. The loading was a process of continuous energy accumulation. When the specimen entered its limit state, the interface was in the maximum stress state, and the accumulated energy was also the largest, resulting in sample failure by brittle fracture. The bonded width of CFRP sheet had a significant effect on the interfacial bearing capacity. The presence of the initial damage in the wood samples destroyed the integrity of the fiber on the wood surface, thus reducing the bearing capacity of the interfacial bond in the composite materials. The bond bearing capacity decreased with an increase in the preexisting damage rate of the wood. In this paper, a calculated expression for the interface stress distribution under the limit state was derived by analyzing the force in micro sections of the bonded interface. The bond bearing capacity model for CFRP-wood interfaces was established and verified with the experimental results. The prediction curve of the interface bond bearing capacity model was in good agreement with the experimental results.