Application of acoustic emission to crack detection and measurement

摘要: See Met. A. , 8109-72 0394. Acoustic emission techniques can, under many circumstances, offer a higher sensitivity to the detection of cracking and greater resolution of the detailed way in which crack propagation occurs than any other laboratory technique. In this review, the detection and measurement of crack extension processes during laboratory testing of metallic materials using the acoustic emission technique is discussed. Details are given of the experimental procedures used to detect acoustic emissions with particular attention to the minimization of the influence of extraneous mechanical and electrical background noise. Attention is then directed to the various ways in which acoustic emission data can be processed, including the use of ring-down counting; event counting; energy analysis; amplitude distribution analysis and frequency spectrum analysis. Finally, the laboratory applications of acoustic …