DYNAMIC DETECTION THE DAMAGE AND FRACTURE PROCESS OF LOAD-BEARING WOOD USING ACOUSTIC EMISSION TECHNOLOGY

This research utilizes three-point bending experiment to simulate actual load-bearing scenarios of wood, and uses acoustic emission monitoring system to collect real-time acoustic emission signal parameters, such as ringing count, energy, amplitude, etc. Analyze the relationship between acoustic emission signals and internal damage during different loading stages, and construct an acoustic emission recognition model for damage and fracture process of elm. Research result shown that during elastic deformation and early plastic deformation stage, the activity of acoustic emission is weak, mainly due to damage and delamination at cell wall, and cell wall buckling and collapse. Entering plastic deformation stage, acoustic emission ringing count and energy significantly increase, corresponding to a large number of cell wall ruptures and microcrack initiation. Near macroscopic fracture stage, high-intensity and high-energy acoustic emission signal clusters appear, indicating rapid propagation of main crack and ultimately leading to fracture.