Estimating mechanical state of AA2024 specimen under tension with the use of Lamb wave based ultrasonic technique

Experimental results on application of ultrasonic technique utilizing Lamb waves for evaluation mechanical state of AA2024T3 specimens under tensile testing are presented. PZTs used as actuators and sensors were glued onto the specimen surface with epoxy adhesive. The set of static tensile tests with two frequencies of acoustic testing (50 kHz and 335 kHz) were performed. The recorded signals were processed to calculate the informative parameters (maximum envelope and 2nd central moment) in order to evaluate the changes of the stress-strain state of the specimen and its microstructure evolution. The relations between acoustic signal features and damages occurring during the loading allow determining the defectiveness of the structure and predicting its residual lifetime.