Volume 26, Issue 6 (November 1998)
Measurement and Interpretation of Fatigue Crack Growth in 7075 Aluminum Alloy Using Acoustic Emission Monitoring
A method for monitoring crack growth during highcycle fatigue tests was demonstrated using acoustic emission (AE) monitoring. Windowing techniques were employed during the recording and interpreting of the AE data. The results provided linear relationships between AE events and amplitudes and crack lengths. The fatigue crack growth results from the AE data were in very good agreement with data measured using an optical microscope.
Fractographic observations of the crack and specimen surfaces showed that secondary cracks formed and linked to the main crack during intermediate stages of crack growth. The crack growth rate calculated from AE data reflected the formation of secondary cracks in this period.