Effect of CFRP winding modes on axial compressive damage performance of wood components

In this study, axial compression test and real-time acoustic emission (AE) monitoring were conducted on six groups of wood components with different carbon fiber reinforced polymers (CFRP) winding methods. The effects of different winding layers and angle on the failure mode, mechanical properties, energy absorption performance, and AE parameter evolution of CFRP-reinforced wood components were analyzed. The results show that the reinforcement of CFRP can significantly improve the mechanical properties of wood and suppress the occurrence of brittle failure. As the CFRP winding layers and angle increase, the ultimate bearing capacity of the wood components increased from 112.63 kN to 161.21 kN, and the displacement ductility factor also increased from 1.44 to 1.72. The increase in the CFRP winding layers and angle can significantly improve the stability and energy absorption capacity of CFRP-reinforced wood components during axial compression damage, and the specific energy absorption (SEA) is increased from 41.68 J center dot g(-1) to 75.01 J center dot g(-1). The damage process of CFRP-reinforced wood components can be divided into three stages: elastic, compressive yield, and damage failure, based on the evolution characteristics of AE ringing counts and time-load curves. With the increase of the winding layers and angle, the AE peak frequency gradually transitions from the low-frequency interval (0-80 kHz) to the high-frequency interval (160-240 kHz), and the form of damage changes from large-scale damage to small-scale damage. The AE energy probability density of wood components with different winding modes follows a power-law scale-free distribution. The critical index increases with the increase of the winding layers and angle, indicating that the reinforcement of CFRP is able to limit the development of internal cracks in wood and attenuate the deterioration of the internal structure. The damage evolution model established based on the relationship between the number of AE cumulative events and load can well reflect the damage evolution law of the material in the axial compression process.