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.

复杂应力状态下的疲劳裂纹是安全评估的关键。由于可视化、快速响应和无损测量的特点，基于机械响应发光（MRL）的方法在应力传感和损伤检测方面具有巨大的潜力。在这项研究中，使用纯有机机械变色发光材料检测了双轴载荷下铝合金中的疲劳裂纹扩展。研究了疲劳裂纹扩展行为和发光发射。使用荧光分布可以成功检测实时疲劳裂纹长度和裂纹扩展路径。基于 MRL 的方法可能会为无损评估和结构损伤评估开辟新的机会。