SEDL / STP / STP505-EB / STP35388S

Amplitude Distribution of Acoustic Emission Signals

Nakamura, Y
General Dynamics Corp., Fort Worth, Tex.

Veach, CL
General Dynamics Corp., Fort Worth, Tex.

McCauley, BO
General Dynamics Corp., Fort Worth, Tex.

Pages: 23    Published: Jan 1972

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Abstract

Acoustic emission signals from slowly growing cracks have been studied experimentally using precracked compact tension specimens of D6ac steel heat treated to several different fracture toughness values but with the same yield strength. The observed signal amplitude is distributed over a range of more than 60 dB, reflecting the statistical nature of the fracture process in a microscopically heterogeneous medium. A clear correlation between the crack growth behavior and the emission amplitude distribution is found. A shift in the amplitude distribution with stress intensity level at a crack tip and a definite difference between the amplitude distribution of emission signals and that of rubbing noise may have direct bearing on the application of the acoustic emission technique as a nondestructive inspection method for materials as well as structural tests.