Wavelet analysis of acoustic emissions associated with cracking in rocks

Acoustic emissions (AEs) are elastic waves, which are generated in solids under stress and are correlated with formation of microfractures in materials. In geological science extensive research has been conducted on seismic signals and AEs in stressed rocks, which signify formation of cracks. A mathematical method is used for frequency analysis of AEs generated in stressed rocks. The result is utilized to extract an equation for the relationship between the crack length and frequency bandwidth of the AEs. The study shows that the effect of the crack length (L) is on the bandwidth of the Acoustic Emission (Delta f(s)) in a way that L = 2 nu(c)/(Delta f(s)-Delta f(x)) where vc is the crack propagation velocity, and Delta f(x) is the bandwidth of the crack mechanism signal. The validity check of the obtained relationship was done by experimental data.