Measurement and interpretation of fatigue crack growth in 7075 aluminum alloy using acoustic emission monitoring

A method for monitoring crack growth during high-cycle fatigue tests was de monstrated using acoustic emission (AE) monitoring. Windowing techniques we re employed during the recording and interpreting of the AE data. The resul ts provided linear relationships between AE events and amplitudes and crack lengths. The fatigue crack growth results from the AE data were in very go od agreement with data measured using an optical microscope. Fractographic observations of the crack and specimen surfaces showed that s econdary cracks formed and linked to the main crack during intermediate sta ges of crack growth. The crack growth rate calculated from AE data reflecte d the formation of secondary I-racks in this period.