Experimental Study On Damage Detection Of Wood Components Based On AE And DIC

It is obvious forms that the damage of wood components is the occurrence of microcracks or even fractures,in order to be able to accurately assess the degree of initial crack damage in wood components,it was usually used as a key parameter to evaluate the safety performance of fracture toughness,and the accuracy of fracture toughness is influenced by the starting load.It cannot be observed of the microcrack sprouting of wood components by the naked eye.Therefore,it can effectively analyze the crack initiation process and surface strain changes of wood components by using acoustic emission system and digital image correlation.This article takes Chinese fir as the research object.It was used to monitor the damage process of wood components under different water content,temperature,and T or L crack conditions from acoustic emission system and digital image correlation,It can be used to obtain the damage evolution rules and cracking loads of wood under different physical conditions by analyzing the cumulative ringing count,amplitude,energy,and other parameter changes as well as the strain field information of wood surface damage and fracture.The specific research contents are as follows:It was studied that cracking load of wood components with different water content based on acoustic emission and digital image correlation.The moisture content was increased of fir components from 0% to 50%,and then sensors were pasted on both sides of the wood short column to receive the sound waves generated by the wood under pressure.At the same time,DIC was used to detect the strain field information on the crack surface of wood components during the process from crack initiation to complete failure.The results show that the degree of internal damage in wood can be reflected based on the cumulative acoustic emission ringing count and amplitude,and DIC can detect the strain changes in the crack tip region of the wood surface in real time.It can be determined of the initiation load by establishing relationships between wood crack initiation and propagation behavior.It was experimental studied what the damage process of wood components at different temperatures was conducted.It was used to detect damage patterns under parallel compression by acoustic emission and digital image correlation and the results show that the higher the temperature,the lower the ultimate load and crack initiation load of wood.In addition,it is verified that the damage index has good applicability in reflecting the damage status of wood components by fitting the damage quantification index DI and Per.It was studied that the damage process of wood components with T-shaped and L-shaped cracks.Firstly,T-shaped and L-shaped crack defects were prefabricated for wood components,and then acoustic emission sensors were used to detect acoustic signals of different wood components under axial compression loading.At the same time,it was used to detect the nano level damage of the wood component by the change of the strain field from the high-speed camera of the digital image system is used to track and capture random speckle patterns on the surface of the test piece to measure the strain field.It can be effectively analyzed the damage process of wood components and the change rule of cracks from initial compaction stage,crack initiation stage,damage aggravation stage,and complete destruction by parameters such as acoustic emission amplitude,cumulative ringing count,and energy.Finally,it is proposed to evaluate the damage degree of different wood components from a damage index,in order to verifying the accuracy what of acoustic emission and digital image methods in predicting the evolution of damage laws...