Experimental Study on Cracking Load of Wood Members under Different Moisture Content

In order to accurately determine the crack initiation law during the damage and fracture of wood components and effectively evaluate the degree of wood damage, in this experiment, Chinese Fir with moisture content of 0%, 20%, 40% and 60% is taken as the research object. Based on acoustic emission（ AE） technology and digital image correlation（ DIC） technology, the damage process of specimens with different moisture content is detected in situ. By analyzing the changes of acoustic emission parameters and the change characteristics of strain curve in the crack surface area, the initiation law and crack initiation load of wood cracks under different moisture content are explored. The results show that the internal damage degree of wood can be reflected based on the cumulative ringing count and amplitude of acoustic emission. DIC can detect the strain change at the tip of wood surface crack in real time, and can effectively judge the crack initiation and propagation according to the change of strain characteristics. The crack initiation load can be accurately determined by establishing the relationship between crack initiation, propagation behavior, acoustic emission and surface strain. The experimental results can provide a theoretical basis for studying the damage mechanism of wood with different physical properties.