MONITORING DAMAGE GROWTH IN TITANIUM MATRIX COMPOSITES USING ACOUSTIC-EMISSION

In this study, an initial application of the acoustic emission (AE) technique to locate and monitor damage growth in a relatively new and advanced titanium matrix composite (TMC) system was investigated. Damage growth was evaluated in SCS-6/Timetal-21S TMC using several optical techniques including a long focal length, high magnification microscope system with image acquisition capabilities. Fracture surface examinations were conducted using a scanning electron microscope (SEM). The AE technique was used to locate damage based on the arrival times of AE events between two sensors. Using model specimens exhibiting a dominant failure mechanism, correlations were established between the observed damage growth mechanisms and the AE results in terms of the events amplitude. The correlation between the damage mechanisms and the AE parameters must be established whenever a new class of material is being evaluated using the AE technique since the AE parameters are highly dependent on the specimen geometry as well as the type of material. These correlations were then used to monitor the damage growth process in laminates exhibiting multiple modes of damage.