Analysis Of Acoustic Emission Signal Of Crack Growth Based On Labview

With the development of acoustic emission equipment, the acoustic emission has been applied in the assessment and monitoring of pressure vessel, pipeline, and large-sale structures etc. However, its application in the signal analysis of cracks development is very few.In addition, restricted by the right of AEwin software complemented, the process of acoustic emission signal demands a software platform with more agility, which can be run in any computer. Under this background, we develop a practical software platform with LabView software for analyzing the waveform and spectrum of single Hit and characteristic parameters of Hit. At the same time, we use this software to process and analyze the data of acoustic emission from static tensile test and fatigue test of 2A12 aluminum and its friction stir welding specimens successfully.In this paper, the tensile stress-strain curve, statistical charts of AE characteristic parameter and the accumulation figure was drawn for friction stir welding (950/300,750/150) specimens of 2A12 aluminum and aluminum alloy. AE signal characteristic for the testing stages of the specimen was anglicized. The analyses for the ultimate Strength of the four friction stir welding specimens, accumulation count under 0-65MPa and 65-130MPa and energy accumulative count, shows that the friction stir welding specimen (950/300) has better integrated performance. AE statistical parameter is highly sensitive to the rotation speed of the welding tool. With the higher the rotation speed, the material of the welding line is mixed better with fewer and smaller defects, and the AE signal and its intensity is less. On the contrary for the lower the rotation speed, the material of the welding line is mixed worse with more and bigger defects, and the AE signal and its intensity is greater.We make the fracture analysis of specimens of 2A12 aluminum under low cycle fatigue, plot the statistical chart of AE characteristic parameter in fatigue test, cumulative chart and exportation Hit rate chart, and mark off the stages of AE signal corresponding to fatigue fracture. It founded that twice main crack merge corresponds to three high-intensity impulse signals.In this paper, we also analyze the AE waveform of total eight Hit for all stages of the fatigue fracture specimens, and spectrum comparison. It is concluded that AE signal characteristic frequency of crack development of 2A12 aluminum alloy in second channel are 225 kHz～250 kHz and 350 kHz～500 kHz.