Comparison of Two Methods in Acoustic Emission Source Location Using Four Sensors Without Measuring Sonic Speed

To eliminate the locating error for acoustic emission system due to the sonic speed measurement deviation, a new nonlinear method of multi-robe locating was proposed. The experiments were carried out in steel pipe and on plane using AE21C4-channel acoustic emission instrument with the signal of pencil lead fracture as simulating source. The results obtained by the new nonlinear method of multi-robe locating were compared with that by analytical method. Results show that the proposed method has only one solution, and it is easy to locate the acoustic emission source any; whereas the analytical method has two solutions, and it has no reasonable solutions in some conditions. It was proved that this new nonlinear method not only has better locating precision, but also it is more convenient than analytical method. To locate the acoustic emission source by the new nonlinear method, only the times when the signals arrive at the probes need to be measured using the threshold crossing technique of the instrument; and the sonic speed of the propagation medium needs no measurement.