3. Acoustic emission fatigue testing: conventional methods

The idea of non-destructive testing of damage and fatigue cracking based on the detection of induced acoustic emissions is a long-standing one. , but based almost exclusively on analysis of the evolution of global variables, such as the average level of "noise" or acoustic energy recorded, or the number of blows dn _c /dN or bursts (dn _s )/(dN) per cycle, detected above a signal amplitude threshold. N is the number of loading cycles. This classic type of analysis, relatively...