Recent developments in quantitative AE

Results of measurements are reviewed for the quantitative evaluation of acoustic emission (AE) with particular attention give to solving the inverse-source problem. Signal processing algorithms are employed to locate an emitting source and identify its temporal and spatial characteristics based solely on signals measured at the surface. Procedures are discussed for identifying the sources in single-fiber composites, determining fiber/matrix interfacial strength, as well as for locating emission sources in anisotropic solids. The point-source/point-receiver (PS/PR) technique is described in detail, in which an artificial point source is incorporated into the measurement system to quantify the propagation of elastic waves from the point to a receiver. A neural network is also described which can enhance the processing of ultrasonic signals for the direct inverse approaches.