Mechanoresponsive luminogen (MRL)-based real-time and visible detection method for biaxial fatigue crack propagation

Fatigue cracks under complex stress state is crucial for safety assessment. Owing to the characteristics of visualization, rapid response and nondestructive measurement, mechanoresponsive luminogen (MRL) based methods have a great potential for stress sensing and damage detection. In this study, fatigue crack propagation in aluminum alloys under biaxial loadings were detected using a pure organic mechanochromic luminescent material. Both fatigue crack propagation behavior and luminescence emission were investigated. Real-time fatigue crack length and crack propagation path can be successfully detected using the fluorescence distribution. The MRL-based methods may open up new opportunities for nondestructive evaluation and structural damage evaluation.