On the possibility of discrimination of mixed mode fatigue fracture mechanisms in adhesive composite joints by advanced acoustic emission analysis

Acoustic emission (AE) from pure and mixed mode fatigue fracture of adhesive composite joints was recorded and analyzed. Transient AE signal classification was attempted by a computational pattern recognition analysis. Good separation was achieved for pure mode AE signals from the double cantilever beam (mode I) and end notch fracture (mode II) tests. AE signals from the mixed mode lap joint test were found to be closer to the mode II fracture signals. The results may provide insight into the fracture mechanisms in joints and can be used for the development of mechanism-based predictive models of fracture and life.