Research On Acoustic Emission Source Location Of Plate

Acoustic emission(AE)technology is a dynamic non-destructive testing technology that can effectively detect the transient elastic wave generated by crack propagation in material.Thus,AE has the ability to forecast the defects and faults in the structure to ensure the safe operation of equipment,which broad development prospect in on-line fault detection.AE source location is the key technology to locate the crack,the key points is infer the source location based on the signal received.In this paper,the pencil-lead breaks were used to generate AE sources,and the TOA source location method as well as a new Delta T source location method was used for AE sources location on simple and complex plates.Afterwards,the performance of two methods is evaluated.The main research work is as follows:(1)An experimental system of AE source location on plate was set up,and the entire experimental system was tested.The wave speed of AE signal was measured.The TOA and Delta T method were used to locate AE source on simple plate.According to the experimental results,the average error of Delta T method was 7.76 mm,the average error of TOA method was 5.33 mm.Thus,the location accuracy of Delta T method is slightly higher than TOA method.(2)For complex plate,two methods were used to locate the AE sources.The experimental results shows that the location error of TOA method increased greatly,some AE sources even cannot be located.For Delta T method,the average error of location is 8.874 mm,which is significantly better than the TOA method.Therefore,the geometry complexity of the object for detection has less influence on the location performance of Delta T method.(3)The influence of different resolutions on Delta T method's location accuracy was studied.Experiment with 25 mm and 50 mm resolutions was conducted.The experimental results shows that at the resolutions of 25 mm,the minimum and the maximum error is 2.555 mm and 14.362 mm.For 50 mm resolution,the minimum and maximum error is 3.256 mm and 25.167 mm,respectively some AE sources even cannot be located.Therefore,higher resolution leads to better location accuracy.The effect of local resolution improvement of Delta T method on location accuracy was studied.The resolution around the holes was improved to 12.5mm,and the average location error was 6.297 mm.When using the globeresolution of 25 mm,the average error rises up to 8.874 mm.Thus,it is possible to achieve location accuracy and reduce workload by just improving the resolution around the complex part of the structure.(4)Source location software was designed based on MATLAB-GUI.Two AE source location software was designed for TOA method and DTM method respectively.