ACOUSTIC EMISSION EVALUATION OF ARAMID REINFORCED ALUMINUM LAMINATE

ARALL shows a good fatigue crack resistance and a high tensile yield strength. Acoustic emission was monitored during tensile tests and loading-holding-unloading cycle tests for two types (notched and unnotched) of ARALL specimens. AE activities showed that the fiber breakage during the tensile tests depended upon the specimen geometry. Results of observations by a scanning electron microscope showed that the delamination also depended upon the specimen geometry. In loading-holding-unloading tests specimens were subjected to ASME standard (Section, V,11). AE activities showed different tendencies from that of the tensile tests. The ratio (Waveform Ratio = Rise time/Duration) of events during the tensile and loading-holding-unloading tests was shown to be a good indicator to distinguish the generated fracture mechanisms, such as delamination, fiber breakage and pull-out obtained from SEM observations.